codes-darshan-io-wrkld.c 58 KB
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/*
 * Copyright (C) 2013 University of Chicago.
 * See COPYRIGHT notice in top-level directory.
 *
 */
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#include <assert.h>
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#include <math.h>
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#include "codes/codes-workload.h"
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#include "codes/quickhash.h"
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#include "codes-workload-method.h"
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#include "darshan-logutils.h"
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#define DEF_INTER_IO_DELAY_PCT 0.2
#define DEF_INTER_CYC_DELAY_PCT 0.4

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#define DARSHAN_NEGLIGIBLE_DELAY .001

#define RANK_HASH_TABLE_SIZE 397

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#define IO_IS_IN_SIZE_BIN_RANGE(size, bin_ndx, bin_min_sizes)                       \
        ((bin_ndx == 9) ?                                                           \
        (size >= bin_min_sizes[bin_ndx]) :                                          \
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        ((size >= bin_min_sizes[bin_ndx]) && (size <= bin_min_sizes[bin_ndx + 1])))

#define MIN(a, b) (((a) < (b)) ? (a) : (b))
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/* structure for storing a darshan workload operation (a codes op with 2 timestamps) */
struct darshan_io_op
{
    struct codes_workload_op codes_op;
    double start_time;
    double end_time;
};

/* I/O context structure managed by each rank in the darshan workload */
struct rank_io_context
{
    int64_t my_rank;
    double last_op_time;
    void *io_op_dat;
    struct qhash_head hash_link;
};

/* Darshan workload generator's implementation of the CODES workload API */
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static int darshan_io_workload_load(const char *params, int rank);
static void darshan_io_workload_get_next(int rank, struct codes_workload_op *op);
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static int darshan_rank_hash_compare(void *key, struct qhash_head *link);

/* Darshan I/O op data structure access (insert, remove) abstraction */
static void *darshan_init_io_op_dat(void);
static void darshan_insert_next_io_op(void *io_op_dat, struct darshan_io_op *io_op);
static void darshan_remove_next_io_op(void *io_op_dat, struct darshan_io_op *io_op,
                                      double last_op_time);
static void darshan_finalize_io_op_dat(void *io_op_dat);
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static void darshan_print_io_ops(void *io_op_dat, int rank, FILE *log_stream);
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static int darshan_io_op_compare(const void *p1, const void *p2);

/* Helper functions for implementing the (complex, nonfactored) Darshan workload generator */
static void generate_psx_ind_file_events(struct darshan_file *file,
                                         struct rank_io_context *io_context);
static void generate_psx_coll_file_events(struct darshan_file *file,
                                          struct rank_io_context *io_context,
                                          int64_t nprocs, int64_t aggregator_cnt);
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static double generate_psx_open_event(struct darshan_file *file, int create_flag,
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                                      double meta_op_time, double cur_time,
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                                      struct rank_io_context *io_context, int insert_flag);
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static double generate_psx_close_event(struct darshan_file *file, double meta_op_time,
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                                       double cur_time, struct rank_io_context *io_context,
                                       int insert_flag);
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static double generate_barrier_event(struct darshan_file *file, int64_t root, double cur_time,
                                     struct rank_io_context *io_context);
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static double generate_psx_ind_io_events(struct darshan_file *file, int64_t io_ops_this_cycle,
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                                         double inter_io_delay, double meta_op_time,
                                         double cur_time, struct rank_io_context *io_context);
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static double generate_psx_coll_io_events(struct darshan_file *file, int64_t ind_io_ops_this_cycle,
                                          int64_t coll_io_ops_this_cycle, int64_t nprocs,
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                                          int64_t aggregator_cnt, double inter_io_delay,
                                          double meta_op_time, double cur_time,
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                                          struct rank_io_context *io_context);
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static void determine_io_params(struct darshan_file *file, int write_flag, int64_t io_this_op,
                                int64_t proc_count, size_t *io_sz, off_t *io_off);
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static void calc_io_delays(struct darshan_file *file, int64_t num_opens, int64_t num_io_ops,
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                           double total_delay, double *first_io_delay, double *close_delay,
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                           double *inter_open_delay, double *inter_io_delay);
static void file_sanity_check(struct darshan_file *file, struct darshan_job *job);

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/* workload method name and function pointers for the CODES workload API */
struct codes_workload_method darshan_io_workload_method =
{
    .method_name = "darshan_io_workload",
    .codes_workload_load = darshan_io_workload_load,
    .codes_workload_get_next = darshan_io_workload_get_next,
};

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/* hash table to store per-rank workload contexts */
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static struct qhash_table *rank_tbl = NULL;
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static int rank_tbl_pop = 0;
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/* load the workload generator for this rank, given input params */
static int darshan_io_workload_load(const char *params, int rank)
{
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    darshan_params *d_params = (darshan_params *)params;
    darshan_fd logfile_fd;
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    struct darshan_job job;
    struct darshan_file next_file;
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    struct rank_io_context *my_ctx;
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    int ret;
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    if (!d_params)
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        return -1;

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    /* open the darshan log to begin reading in file i/o info */
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    logfile_fd = darshan_log_open(d_params->log_file_path, "r");
    if (logfile_fd < 0)
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        return -1;
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    /* get the per-job stats from the log */
    ret = darshan_log_getjob(logfile_fd, &job);
    if (ret < 0)
    {
        darshan_log_close(logfile_fd);
        return -1;
    }

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    /* allocate the i/o context needed by this rank */
    my_ctx = malloc(sizeof(struct rank_io_context));
    if (!my_ctx)
    {
        darshan_log_close(logfile_fd);
        return -1;
    }
    my_ctx->my_rank = (int64_t)rank;
    my_ctx->last_op_time = 0.0;
    my_ctx->io_op_dat = darshan_init_io_op_dat();

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    /* loop over all files contained in the log file */
    while ((ret = darshan_log_getfile(logfile_fd, &job, &next_file)) > 0)
    {
        /* generate all i/o events contained in this independent file */
        if (next_file.rank == rank)
        {
            /* make sure the file i/o counters are valid */
            file_sanity_check(&next_file, &job);

            /* generate i/o events and store them in this rank's workload context */
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            generate_psx_ind_file_events(&next_file, my_ctx);
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        }
        /* generate all i/o events involving this rank in this collective file */
        else if (next_file.rank == -1)
        {
            /* make sure the file i/o counters are valid */
            file_sanity_check(&next_file, &job);
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            /* generate collective i/o events and store them in the rank context */
            generate_psx_coll_file_events(&next_file, my_ctx, job.nprocs, d_params->aggregator_cnt);
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        }
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        else
            continue;
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        assert(next_file.counters[CP_POSIX_OPENS] == 0);
        assert(next_file.counters[CP_POSIX_READS] == 0);
        assert(next_file.counters[CP_POSIX_WRITES] == 0);
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    }
    if (ret < 0)
        return -1;

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    darshan_log_close(logfile_fd);
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    /* finalize the rank's i/o context so i/o ops may be retrieved later (in order) */
    darshan_finalize_io_op_dat(my_ctx->io_op_dat);

    /* initialize the hash table of rank contexts, if it has not been initialized */
    if (!rank_tbl)
    {
        rank_tbl = qhash_init(darshan_rank_hash_compare, quickhash_64bit_hash, RANK_HASH_TABLE_SIZE);
        if (!rank_tbl)
            return -1;
    }

    /* add this rank context to the hash table */
    qhash_add(rank_tbl, &(my_ctx->my_rank), &(my_ctx->hash_link));
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    rank_tbl_pop++;
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    /* TODO: do we want this long-term */
    if (d_params->stream)
    {
        darshan_print_io_ops(my_ctx->io_op_dat, rank, d_params->stream);
    }
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    return 0;
}

/* pull the next event (independent or collective) for this rank from its event context */
static void darshan_io_workload_get_next(int rank, struct codes_workload_op *op)
{
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    int64_t my_rank = (int64_t)rank;
    struct qhash_head *hash_link = NULL;
    struct rank_io_context *tmp = NULL;
    struct darshan_io_op next_io_op;

    /* find i/o context for this rank in the rank hash table */
    hash_link = qhash_search(rank_tbl, &my_rank);

    /* terminate the workload if there is no valid rank context */
    if (!hash_link)
    {
        op->op_type = CODES_WK_END;
        return;
    }

    /* get access to the rank's io_context data */
    tmp = qhash_entry(hash_link, struct rank_io_context, hash_link);
    assert(tmp->my_rank == my_rank);

    /* get the next darshan i/o op out of this rank's context */
    darshan_remove_next_io_op(tmp->io_op_dat, &next_io_op, tmp->last_op_time);

    /* free the rank's i/o context if this is the last i/o op */
    if (next_io_op.codes_op.op_type == CODES_WK_END)
    {
        qhash_del(hash_link);
        free(tmp);
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        rank_tbl_pop--;
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        if (!rank_tbl_pop){
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            qhash_finalize(rank_tbl);
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            rank_tbl = NULL;
        }
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    }
    else
    {
        /* else, set the last op time to be the end of the returned op */
        tmp->last_op_time = next_io_op.end_time;
    }

    /* return the codes op contained in the darshan i/o op */
    *op = next_io_op.codes_op;
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    return;
}

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/* comparison function for comparing two hash keys (used for storing multiple io contexts) */
static int darshan_rank_hash_compare(
    void *key, struct qhash_head *link)
{
    int64_t *in_rank = (int64_t *)key;
    struct rank_io_context *tmp;

    tmp = qhash_entry(link, struct rank_io_context, hash_link);
    if (tmp->my_rank == *in_rank)
        return 1;

    return 0;
}

/*****************************************/
/*                                       */
/*   Darshan I/O op storage abstraction  */
/*                                       */
/*****************************************/

#define DARSHAN_IO_OP_INC_CNT 100000

/* dynamically allocated array data structure for storing darshan i/o events */
struct darshan_io_dat_array
{
    struct darshan_io_op *op_array;
    int64_t op_arr_ndx;
    int64_t op_arr_cnt;
};

/* initialize the dynamic array data structure */
static void *darshan_init_io_op_dat()
{
    struct darshan_io_dat_array *tmp;

    /* initialize the array data structure */
    tmp = malloc(sizeof(struct darshan_io_dat_array));
    assert(tmp);
    tmp->op_array = malloc(DARSHAN_IO_OP_INC_CNT * sizeof(struct darshan_io_op));
    assert(tmp->op_array);
    tmp->op_arr_ndx = 0;
    tmp->op_arr_cnt = DARSHAN_IO_OP_INC_CNT;

    /* return the array info for this rank's i/o context */
    return (void *)tmp;
}

/* store the i/o event in this rank's i/o context */
static void darshan_insert_next_io_op(
    void *io_op_dat, struct darshan_io_op *io_op)
{
    struct darshan_io_dat_array *array = (struct darshan_io_dat_array *)io_op_dat;
    struct darshan_io_op *tmp;

    /* realloc array if it is already full */
    if (array->op_arr_ndx == array->op_arr_cnt)
    {
        tmp = malloc((array->op_arr_cnt + DARSHAN_IO_OP_INC_CNT) * sizeof(struct darshan_io_op));
        assert(tmp);
        memcpy(tmp, array->op_array, array->op_arr_cnt * sizeof(struct darshan_io_op));
        free(array->op_array);
        array->op_array = tmp;
        array->op_arr_cnt += DARSHAN_IO_OP_INC_CNT;
    }

    /* add the darshan i/o op to the array */
    array->op_array[array->op_arr_ndx++] = *io_op;

    return;
}

/* pull the next i/o event out of this rank's i/o context */
static void darshan_remove_next_io_op(
    void *io_op_dat, struct darshan_io_op *io_op, double last_op_time)
{
    struct darshan_io_dat_array *array = (struct darshan_io_dat_array *)io_op_dat;

    /* if the array has been scanned completely already */
    if (array->op_arr_ndx == array->op_arr_cnt)
    {
        /* no more events just end the workload */
        io_op->codes_op.op_type = CODES_WK_END;

        /* free data structures */
        free(array->op_array);
        free(array);
    }
    else
    {
        struct darshan_io_op *tmp = &(array->op_array[array->op_arr_ndx]);

        if ((tmp->start_time - last_op_time) < DARSHAN_NEGLIGIBLE_DELAY)
        {
            /* there is no delay, just return the next op in the array */
            *io_op = *tmp;
            array->op_arr_ndx++;
        }
        else
        {
            /* there is a nonnegligible delay, so generate and return a delay event */
            io_op->codes_op.op_type = CODES_WK_DELAY;
            io_op->codes_op.u.delay.seconds = tmp->start_time - last_op_time;
            io_op->start_time = last_op_time;
            io_op->end_time = tmp->start_time;
        }
    }
}

/* sort the dynamic array in order of i/o op start time */
static void darshan_finalize_io_op_dat(
    void *io_op_dat)
{
    struct darshan_io_dat_array *array = (struct darshan_io_dat_array *)io_op_dat;

    /* sort this rank's i/o op list */
    qsort(array->op_array, array->op_arr_ndx, sizeof(struct darshan_io_op), darshan_io_op_compare);
    array->op_arr_cnt = array->op_arr_ndx;
    array->op_arr_ndx = 0;

    return;
}

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/* print the events for this rank in order */
void darshan_print_io_ops(void *io_op_dat, int rank, FILE *log_stream)
{
    struct darshan_io_dat_array *io_array = (struct darshan_io_dat_array *)io_op_dat;
    struct darshan_io_op *event_list = io_array->op_array;
    int64_t event_list_cnt = io_array->op_arr_cnt;
    int64_t i;

    if (!event_list_cnt)
        return;

    for (i = 0; i < event_list_cnt; i++)
    {
        if (event_list[i].codes_op.op_type == CODES_WK_OPEN)
        {
            if (event_list[i].codes_op.u.open.create_flag == 0)
            {
                fprintf(log_stream, "Rank %d OPEN %"PRIu64" (%lf - %lf)\n",
                        rank,
                        event_list[i].codes_op.u.open.file_id,
                        event_list[i].start_time,
                        event_list[i].end_time);
            }
            else
            {
                fprintf(log_stream, "Rank %d CREATE %"PRIu64" (%lf - %lf)\n",
                        rank,
                        event_list[i].codes_op.u.open.file_id,
                        event_list[i].start_time,
                        event_list[i].end_time);
            }
        }
        else if (event_list[i].codes_op.op_type == CODES_WK_CLOSE)
        {
            fprintf(log_stream, "Rank %d CLOSE %"PRIu64" (%lf - %lf)\n",
                    rank,
                    event_list[i].codes_op.u.close.file_id,
                    event_list[i].start_time,
                    event_list[i].end_time);
        }
        else if (event_list[i].codes_op.op_type == CODES_WK_READ)
        {
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            fprintf(log_stream, "Rank %d READ %"PRIu64" [sz = %"PRId64", off = %"PRId64
                    "] (%lf - %lf)\n",
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                    rank,
                    event_list[i].codes_op.u.read.file_id,
                    (int64_t)event_list[i].codes_op.u.read.size,
                    (int64_t)event_list[i].codes_op.u.read.offset,
                    event_list[i].start_time,
                    event_list[i].end_time);
        }
        else if (event_list[i].codes_op.op_type == CODES_WK_WRITE)
        {
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            fprintf(log_stream, "Rank %d WRITE %"PRIu64" [sz = %"PRId64", off = %"PRId64
                    "] (%lf - %lf)\n",
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                    rank,
                    event_list[i].codes_op.u.write.file_id,
                    (int64_t)event_list[i].codes_op.u.write.size,
                    (int64_t)event_list[i].codes_op.u.write.offset,
                    event_list[i].start_time,
                    event_list[i].end_time);
        }
        else if (event_list[i].codes_op.op_type == CODES_WK_BARRIER)
        {
            fprintf(log_stream, "****");
        }
    }

    return;
}

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/* comparison function for sorting darshan_io_ops in order of start timestamps */
static int darshan_io_op_compare(
    const void *p1, const void *p2)
{
    struct darshan_io_op *a = (struct darshan_io_op *)p1;
    struct darshan_io_op *b = (struct darshan_io_op *)p2;

    if (a->start_time < b->start_time)
        return -1;
    else if (a->start_time > b->start_time)
        return 1;
    else
        return 0;
}

/*****************************************/
/*                                       */
/* Darshan workload generation functions */
/*                                       */
/*****************************************/
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/* generate events for an independently opened file, and store these events */
static void generate_psx_ind_file_events(
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    struct darshan_file *file, struct rank_io_context *io_context)
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{
    int64_t io_ops_this_cycle;
    double cur_time = file->fcounters[CP_F_OPEN_TIMESTAMP];
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    double total_delay;
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    double first_io_delay = 0.0;
    double close_delay = 0.0;
    double inter_open_delay = 0.0;
    double inter_io_delay = 0.0;
    double meta_op_time;
    int create_flag;
    int64_t i;

    /* if the file was never really opened, just return because we have no timing info */
    if (file->counters[CP_POSIX_OPENS] == 0)
        return;

    /* determine delay available per open-io-close cycle */
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    total_delay = file->fcounters[CP_F_CLOSE_TIMESTAMP] - file->fcounters[CP_F_OPEN_TIMESTAMP] -
                  file->fcounters[CP_F_POSIX_READ_TIME] - file->fcounters[CP_F_POSIX_WRITE_TIME] -
                  file->fcounters[CP_F_POSIX_META_TIME];
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    /* calculate synthetic delay values */
    calc_io_delays(file, file->counters[CP_POSIX_OPENS],
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                   file->counters[CP_POSIX_READS] + file->counters[CP_POSIX_WRITES], total_delay,
                   &first_io_delay, &close_delay, &inter_open_delay, &inter_io_delay);
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    /* calculate average meta op time (for i/o and opens/closes) */
    /* TODO: this needs to be updated when we add in stat, seek, etc. */
    meta_op_time = file->fcounters[CP_F_POSIX_META_TIME] / ((2 * file->counters[CP_POSIX_OPENS]) +
                   file->counters[CP_POSIX_READS] + file->counters[CP_POSIX_WRITES]);

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    /* set the create flag if the file was written to */
    if (file->counters[CP_BYTES_WRITTEN])
    {
        create_flag = 1;
    }
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    /* generate open/io/close events for all cycles */
    /* TODO: add stats */
    for (i = 0; file->counters[CP_POSIX_OPENS]; i++, file->counters[CP_POSIX_OPENS]--)
    {
        /* generate an open event */
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        cur_time = generate_psx_open_event(file, create_flag, meta_op_time, cur_time,
                                           io_context, 1);
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        create_flag = 0;

        /* account for potential delay from first open to first io */
        cur_time += first_io_delay;

        io_ops_this_cycle = ceil((double)(file->counters[CP_POSIX_READS] +
                                 file->counters[CP_POSIX_WRITES]) /
                                 file->counters[CP_POSIX_OPENS]);

        /* perform the calculated number of i/o operations for this file open */
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        cur_time = generate_psx_ind_io_events(file, io_ops_this_cycle, inter_io_delay,
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                                              meta_op_time, cur_time, io_context);
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        /* account for potential delay from last io to close */
        cur_time += close_delay;

        /* generate a close for the open event at the start of the loop */
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        cur_time = generate_psx_close_event(file, meta_op_time, cur_time, io_context, 1);
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        /* account for potential interopen delay if more than one open */
        if (file->counters[CP_POSIX_OPENS] > 1)
        {
            cur_time += inter_open_delay;
        }
    }
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    return;
}

/* generate events for the i/o ops stored in a collectively opened file for this rank */
void generate_psx_coll_file_events(
    struct darshan_file *file, struct rank_io_context *io_context,
    int64_t nprocs, int64_t in_agg_cnt)
{
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    int64_t open_cycles;
    int64_t total_ind_opens;
    int64_t total_coll_opens;
    int64_t ind_opens_this_cycle;
    int64_t coll_opens_this_cycle;
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    int64_t extra_opens = 0;
    int64_t extra_io_ops = 0;
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    int64_t total_io_ops = file->counters[CP_POSIX_READS] + file->counters[CP_POSIX_WRITES];
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    int64_t total_ind_io_ops;
    int64_t total_coll_io_ops;
    int64_t ind_io_ops_this_cycle;
    int64_t coll_io_ops_this_cycle;
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    int64_t rank_cnt;
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    int create_flag = 0;
    double cur_time = file->fcounters[CP_F_OPEN_TIMESTAMP];
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    double total_delay;
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    double first_io_delay = 0.0;
    double close_delay = 0.0;
    double inter_cycle_delay = 0.0;
    double inter_io_delay = 0.0;
    double meta_op_time;
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    int64_t i;
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    /* the collective file was never opened (i.e., just stat-ed), so return */
    if (!(file->counters[CP_POSIX_OPENS]))
        return;

    /*  in this case, posix opens are less than mpi opens...
     *  this is probably a mpi deferred open -- assume app will not use this, currently.
     */
    assert(file->counters[CP_POSIX_OPENS] >= nprocs);

571 572
    if (file->counters[CP_COLL_OPENS] || file->counters[CP_INDEP_OPENS])
    {
573 574
        extra_opens = file->counters[CP_POSIX_OPENS] - file->counters[CP_COLL_OPENS] -
                      file->counters[CP_INDEP_OPENS];
575

576 577
        total_coll_opens = file->counters[CP_COLL_OPENS];
        total_ind_opens = file->counters[CP_POSIX_OPENS] - total_coll_opens - extra_opens;
578 579 580 581

        total_ind_io_ops = file->counters[CP_INDEP_READS] + file->counters[CP_INDEP_WRITES];
        total_coll_io_ops = (file->counters[CP_COLL_READS] + file->counters[CP_COLL_WRITES]) / nprocs;

582 583 584 585 586 587 588 589
        if (file->counters[CP_COLL_OPENS])
        {
            total_delay = (file->fcounters[CP_F_CLOSE_TIMESTAMP] -
                           file->fcounters[CP_F_OPEN_TIMESTAMP] -
                           (file->fcounters[CP_F_POSIX_READ_TIME] / in_agg_cnt) -
                           (file->fcounters[CP_F_POSIX_WRITE_TIME] / in_agg_cnt) -
                           (file->fcounters[CP_F_POSIX_META_TIME] / in_agg_cnt));

590
            open_cycles = total_coll_opens / nprocs;
591 592 593 594
            calc_io_delays(file, ceil(((double)(total_coll_opens + total_ind_opens)) / nprocs),
                           total_coll_io_ops + ceil((double)total_ind_io_ops / nprocs), total_delay,
                           &first_io_delay, &close_delay, &inter_cycle_delay, &inter_io_delay);
        }
595
        else
596 597 598 599 600 601
        {
            total_delay = (file->fcounters[CP_F_CLOSE_TIMESTAMP] -
                           file->fcounters[CP_F_OPEN_TIMESTAMP] -
                           (file->fcounters[CP_F_POSIX_READ_TIME] / nprocs) -
                           (file->fcounters[CP_F_POSIX_WRITE_TIME] / nprocs) -
                           (file->fcounters[CP_F_POSIX_META_TIME] / nprocs));
602

603 604 605 606
            open_cycles = ceil((double)total_ind_opens / nprocs);
            calc_io_delays(file, open_cycles, ceil((double)total_ind_io_ops / nprocs), total_delay,
                           &first_io_delay, &close_delay, &inter_cycle_delay, &inter_io_delay);
        }
607 608 609 610 611 612 613 614 615 616 617
    }
    else
    {
        extra_opens = file->counters[CP_POSIX_OPENS] % nprocs;
        if (extra_opens && ((file->counters[CP_POSIX_OPENS] / nprocs) % extra_opens))
        {
            extra_opens = 0;
        }
        else
        {
            extra_io_ops = total_io_ops % nprocs;
618 619 620 621 622
            if (extra_io_ops != extra_opens)
            {
                extra_opens = 0;
                extra_io_ops = 0;
            }
623 624 625
        }

        total_coll_opens = 0;
626
        total_ind_opens = file->counters[CP_POSIX_OPENS] - extra_opens;
627 628 629

        total_ind_io_ops = total_io_ops - extra_io_ops;
        total_coll_io_ops = 0;
630

631 632 633 634 635 636
        total_delay = (file->fcounters[CP_F_CLOSE_TIMESTAMP] -
                       file->fcounters[CP_F_OPEN_TIMESTAMP] -
                       (file->fcounters[CP_F_POSIX_READ_TIME] / nprocs) -
                       (file->fcounters[CP_F_POSIX_WRITE_TIME] / nprocs) -
                       (file->fcounters[CP_F_POSIX_META_TIME] / nprocs));

637 638 639
        open_cycles = ceil((double)total_ind_opens / nprocs);
        calc_io_delays(file, open_cycles, ceil((double)total_ind_io_ops / nprocs), total_delay,
                       &first_io_delay, &close_delay, &inter_cycle_delay, &inter_io_delay);
640 641 642
    }
    assert(extra_opens <= open_cycles);

643 644 645 646
    /* calculate average meta op time (for i/o and opens/closes) */
    meta_op_time = file->fcounters[CP_F_POSIX_META_TIME] / ((2 * file->counters[CP_POSIX_OPENS]) +
                   file->counters[CP_POSIX_READS] + file->counters[CP_POSIX_WRITES]);

647 648 649 650 651
    /* it is rare to overwrite existing files, so set the create flag */
    if (file->counters[CP_BYTES_WRITTEN])
    {
        create_flag = 1;
    }
652

653 654
    /* generate all events for this collectively opened file */
    for (i = 0; i < open_cycles; i++)
655
    {
656 657
        ind_opens_this_cycle = ceil((double)total_ind_opens / (open_cycles - i));
        coll_opens_this_cycle = total_coll_opens / (open_cycles - i);
658

659 660 661
        /* assign any extra opens to rank 0 (these may correspond to file creations or
         * header reads/writes)
         */
662
        if (extra_opens && !(i % (open_cycles / extra_opens)))
663
        {
664 665
            cur_time = generate_psx_open_event(file, create_flag, meta_op_time, cur_time,
                                               io_context, (io_context->my_rank == 0));
666 667
            create_flag = 0;

668 669 670 671 672 673
            if (!file->counters[CP_COLL_OPENS] && !file->counters[CP_INDEP_OPENS])
            {
                cur_time = generate_psx_coll_io_events(file, 1, 0, nprocs, nprocs, 0.0,
                                                       meta_op_time, cur_time, io_context);
                extra_io_ops--;
            }
674

675 676
            cur_time = generate_psx_close_event(file, meta_op_time, cur_time, io_context,
                                                (io_context->my_rank == 0));
677 678 679
            file->counters[CP_POSIX_OPENS]--;
        }

680
        while (ind_opens_this_cycle)
681
        {
682 683 684 685 686
            if (ind_opens_this_cycle >= nprocs)
                rank_cnt = nprocs;
            else
                rank_cnt = ind_opens_this_cycle;

687 688
            cur_time = generate_psx_open_event(file, create_flag, meta_op_time, cur_time,
                                               io_context, (io_context->my_rank < rank_cnt));
689 690
            create_flag = 0;

691 692 693 694
            cur_time += first_io_delay;

            ind_io_ops_this_cycle = ceil(((double)total_ind_io_ops / total_ind_opens) * rank_cnt);
            cur_time = generate_psx_coll_io_events(file, ind_io_ops_this_cycle, 0, nprocs,
695
                                                   nprocs, inter_io_delay, meta_op_time,
696 697 698 699
                                                   cur_time, io_context);
            total_ind_io_ops -= ind_io_ops_this_cycle;

            cur_time += close_delay;
700

701 702
            cur_time = generate_psx_close_event(file, meta_op_time, cur_time, io_context,
                                                (io_context->my_rank < rank_cnt));
703

704 705 706 707 708 709
            file->counters[CP_POSIX_OPENS] -= rank_cnt;
            ind_opens_this_cycle -= rank_cnt;
            total_ind_opens -= rank_cnt;

            if (file->counters[CP_POSIX_OPENS])
                cur_time += inter_cycle_delay;
710 711
        }

712
        while (coll_opens_this_cycle)
713
        {
714
            assert(!create_flag);
715

716
            cur_time = generate_barrier_event(file, 0, cur_time, io_context);
717 718

            cur_time = generate_psx_open_event(file, create_flag, meta_op_time,
719
                                               cur_time, io_context, 1);
720

721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738
            cur_time += first_io_delay;

            if (file->counters[CP_INDEP_OPENS])
                ind_io_ops_this_cycle = 0;
            else
                ind_io_ops_this_cycle = ceil((double)total_ind_io_ops / 
                                             (file->counters[CP_COLL_OPENS] / nprocs));

            coll_io_ops_this_cycle = ceil((double)total_coll_io_ops / 
                                          (file->counters[CP_COLL_OPENS] / nprocs));
            cur_time = generate_psx_coll_io_events(file, ind_io_ops_this_cycle,
                                                   coll_io_ops_this_cycle, nprocs, in_agg_cnt,
                                                   inter_io_delay, meta_op_time,
                                                   cur_time, io_context);
            total_ind_io_ops -= ind_io_ops_this_cycle;
            total_coll_io_ops -= coll_io_ops_this_cycle;

            cur_time += close_delay;
739

740
            cur_time = generate_psx_close_event(file, meta_op_time, cur_time, io_context, 1);
741 742

            file->counters[CP_POSIX_OPENS] -= nprocs;
743 744
            file->counters[CP_COLL_OPENS] -= nprocs;
            coll_opens_this_cycle -= nprocs;
745 746 747 748
            total_coll_opens -= nprocs;

            if (file->counters[CP_POSIX_OPENS])
                cur_time += inter_cycle_delay;
749 750
        }
    }
751 752 753 754 755 756

    return;
}

/* fill in an open event structure and store it with the rank context */
static double generate_psx_open_event(
757
    struct darshan_file *file, int create_flag, double meta_op_time,
758
    double cur_time, struct rank_io_context *io_context, int insert_flag)
759
{
760 761 762 763 764 765 766
    struct darshan_io_op next_io_op = 
    {
        .codes_op.op_type = CODES_WK_OPEN,
        .codes_op.u.open.file_id = file->hash,
        .codes_op.u.open.create_flag = create_flag,
        .start_time = cur_time
    };
767 768 769

    /* set the end time of the event based on time spent in POSIX meta operations */
    cur_time += meta_op_time;
770
    next_io_op.end_time = cur_time;
771

772
    /* store the open event (if this rank performed it) */
773
    if (insert_flag)
774
        darshan_insert_next_io_op(io_context->io_op_dat, &next_io_op);
775 776 777 778 779 780

    return cur_time;
}

/* fill in a close event structure and store it with the rank context */
static double generate_psx_close_event(
781
    struct darshan_file *file, double meta_op_time, double cur_time,
782
    struct rank_io_context *io_context, int insert_flag)
783
{
784 785 786 787 788 789
    struct darshan_io_op next_io_op =
    {
        .codes_op.op_type = CODES_WK_CLOSE,
        .codes_op.u.close.file_id = file->hash,
        .start_time = cur_time
    };
790 791 792

    /* set the end time of the event based on time spent in POSIX meta operations */
    cur_time += meta_op_time;
793
    next_io_op.end_time = cur_time;
794

795
    /* store the close event (if this rank performed it) */
796
    if (insert_flag)
797
        darshan_insert_next_io_op(io_context->io_op_dat, &next_io_op);
798 799 800 801 802 803

    return cur_time;
}

/* fill in a barrier event structure and store it with the rank context */
static double generate_barrier_event(
804
    struct darshan_file *file, int64_t root, double cur_time, struct rank_io_context *io_context)
805
{
806 807 808 809 810 811 812
    struct darshan_io_op next_io_op =
    {
        .codes_op.op_type = CODES_WK_BARRIER, 
        .codes_op.u.barrier.count = -1, /* all processes */
        .codes_op.u.barrier.root = root,
        .start_time = cur_time
    };
813 814

    cur_time += .000001; /* small synthetic delay representing time to barrier */
815
    next_io_op.end_time = cur_time;
816

817
    /* store the barrier event */
818
    if (file->rank == -1)
819
        darshan_insert_next_io_op(io_context->io_op_dat, &next_io_op);
820 821 822 823 824 825

    return cur_time;
}

/* generate all i/o events for one independent file open and store them with the rank context */
static double generate_psx_ind_io_events(
826 827
    struct darshan_file *file, int64_t io_ops_this_cycle, double inter_io_delay,
    double meta_op_time, double cur_time, struct rank_io_context *io_context)
828 829 830 831 832 833 834 835 836
{
    static int rw = -1; /* rw = 1 for write, 0 for read, -1 for uninitialized */
    static int64_t io_ops_this_rw;
    static double rd_bw = 0.0, wr_bw = 0.0;
    int64_t psx_rw_ops_remaining = file->counters[CP_POSIX_READS] + file->counters[CP_POSIX_WRITES];
    double io_op_time;
    size_t io_sz;
    off_t io_off;
    int64_t i;
837
    struct darshan_io_op next_io_op;
838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873

    /* if there are no i/o ops, just return immediately */
    if (!io_ops_this_cycle)
        return cur_time;

    /* initialze static variables when a new file is opened */
    if (rw == -1)
    {
        /* initialize rw to be the first i/o operation found in the log */
        if (file->fcounters[CP_F_WRITE_START_TIMESTAMP] == 0.0)
            rw = 0;
        else if (file->fcounters[CP_F_READ_START_TIMESTAMP] == 0.0)
            rw = 1;
        else
            rw = (file->fcounters[CP_F_READ_START_TIMESTAMP] <
                  file->fcounters[CP_F_WRITE_START_TIMESTAMP]) ? 0 : 1;

        /* determine how many io ops to do before next rw switch */
        if (!rw)
            io_ops_this_rw = file->counters[CP_POSIX_READS] /
                             ((file->counters[CP_RW_SWITCHES] / 2) + 1);
        else
            io_ops_this_rw = file->counters[CP_POSIX_WRITES] /
                             ((file->counters[CP_RW_SWITCHES] / 2) + 1);

        /* initialize the rd and wr bandwidth values using total io size and time */
        if (file->fcounters[CP_F_POSIX_READ_TIME])
            rd_bw = file->counters[CP_BYTES_READ] / file->fcounters[CP_F_POSIX_READ_TIME];
        if (file->fcounters[CP_F_POSIX_WRITE_TIME])
            wr_bw = file->counters[CP_BYTES_WRITTEN] / file->fcounters[CP_F_POSIX_WRITE_TIME];
    }

    /* loop to generate all reads/writes for this open/close sequence */
    for (i = 0; i < io_ops_this_cycle; i++)
    {
        /* calculate what value to use for i/o size and offset */
874
        determine_io_params(file, rw, 1, 1, &io_sz, &io_off);
875 876 877
        if (!rw)
        {
            /* generate a read event */
878 879 880 881 882
            next_io_op.codes_op.op_type = CODES_WK_READ;
            next_io_op.codes_op.u.read.file_id = file->hash;
            next_io_op.codes_op.u.read.size = io_sz;
            next_io_op.codes_op.u.read.offset = io_off;
            next_io_op.start_time = cur_time;
883 884 885 886 887

            /* set the end time based on observed bandwidth and io size */
            if (rd_bw == 0.0)
                io_op_time = 0.0;
            else
888
                io_op_time = (io_sz / rd_bw);
889 890 891

            /* update time, accounting for metadata time */
            cur_time += (io_op_time + meta_op_time);
892
            next_io_op.end_time = cur_time;
893 894 895 896 897
            file->counters[CP_POSIX_READS]--;
        }
        else
        {
            /* generate a write event */
898 899 900 901 902
            next_io_op.codes_op.op_type = CODES_WK_WRITE;
            next_io_op.codes_op.u.write.file_id = file->hash;
            next_io_op.codes_op.u.write.size = io_sz;
            next_io_op.codes_op.u.write.offset = io_off;
            next_io_op.start_time = cur_time;
903 904 905 906 907

            /* set the end time based on observed bandwidth and io size */
            if (wr_bw == 0.0)
                io_op_time = 0.0;
            else
908
                io_op_time = (io_sz / wr_bw);
909 910 911

            /* update time, accounting for metadata time */
            cur_time += (io_op_time + meta_op_time);
912
            next_io_op.end_time = cur_time;
913 914 915 916 917 918 919
            file->counters[CP_POSIX_WRITES]--;
        }
        psx_rw_ops_remaining--;
        io_ops_this_rw--;
        assert(file->counters[CP_POSIX_READS] >= 0);
        assert(file->counters[CP_POSIX_WRITES] >= 0);

920 921
        /* store the i/o event */
        darshan_insert_next_io_op(io_context->io_op_dat, &next_io_op);
922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941

        /* determine whether to toggle between reads and writes */
        if (!io_ops_this_rw && psx_rw_ops_remaining)
        {
            /* toggle the read/write flag */
            rw ^= 1;
            file->counters[CP_RW_SWITCHES]--;

            /* determine how many io ops to do before next rw switch */
            if (!rw)
                io_ops_this_rw = file->counters[CP_POSIX_READS] /
                                 ((file->counters[CP_RW_SWITCHES] / 2) + 1);
            else
                io_ops_this_rw = file->counters[CP_POSIX_WRITES] /
                                 ((file->counters[CP_RW_SWITCHES] / 2) + 1);
        }

        if (i != (io_ops_this_cycle - 1))
        {
            /* update current time to account for possible delay between i/o operations */
942
            cur_time += inter_io_delay;
943 944 945 946 947 948 949 950 951 952 953 954
        }
    }

    /* reset the static rw flag if this is the last open-close cycle for this file */
    if (file->counters[CP_POSIX_OPENS] == 1)
    {
        rw = -1;
    }

    return cur_time;
}

955 956
static double generate_psx_coll_io_events(
    struct darshan_file *file, int64_t ind_io_ops_this_cycle, int64_t coll_io_ops_this_cycle,
957 958
    int64_t nprocs, int64_t aggregator_cnt, double inter_io_delay, double meta_op_time,
    double cur_time, struct rank_io_context *io_context)
959 960 961 962 963 964 965 966 967 968 969 970
{
    static int rw = -1; /* rw = 1 for write, 0 for read, -1 for uninitialized */
    static int64_t io_ops_this_rw;
    static double rd_bw = 0.0, wr_bw = 0.0;
    int64_t psx_rw_ops_remaining = file->counters[CP_POSIX_READS] + file->counters[CP_POSIX_WRITES];
    int64_t total_io_ops_this_cycle = ind_io_ops_this_cycle + coll_io_ops_this_cycle;
    int64_t total_coll_io_ops =
            (file->counters[CP_COLL_READS] + file->counters[CP_COLL_WRITES]) / nprocs;
    int64_t tmp_rank;
    int64_t next_ind_io_rank = 0;
    int64_t io_cnt;
    int64_t ranks_per_aggregator = nprocs / aggregator_cnt;
971
    int64_t ind_ops_remaining = 0;
972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994
    double io_op_time;
    double max_cur_time = 0.0;
    int ind_coll;
    size_t io_sz;
    off_t io_off;
    int64_t i, j;
    struct darshan_io_op next_io_op;

    if (!total_io_ops_this_cycle)
        return cur_time;

    /* initialze static variables when a new file is opened */
    if (rw == -1)
    {
        /* initialize rw to be the first i/o operation found in the log */
        if (file->fcounters[CP_F_WRITE_START_TIMESTAMP] == 0.0)
            rw = 0;
        else if (file->fcounters[CP_F_READ_START_TIMESTAMP] == 0.0)
            rw = 1;
        else
            rw = (file->fcounters[CP_F_READ_START_TIMESTAMP] <
                  file->fcounters[CP_F_WRITE_START_TIMESTAMP]) ? 0 : 1;

995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016
        /* determine how many io ops to do before next rw switch */
        if (!rw)
        {
            if (file->counters[CP_COLL_OPENS])
                io_ops_this_rw =
                    ((file->counters[CP_COLL_READS] / nprocs) + file->counters[CP_INDEP_READS]) /
                    ((file->counters[CP_RW_SWITCHES] / (2 * aggregator_cnt)) + 1);
            else
                io_ops_this_rw = file->counters[CP_POSIX_READS] /
                                 ((file->counters[CP_RW_SWITCHES] / (2 * aggregator_cnt)) + 1);
        }
        else
        {
            if (file->counters[CP_COLL_OPENS])
                io_ops_this_rw =
                    ((file->counters[CP_COLL_WRITES] / nprocs) + file->counters[CP_INDEP_WRITES]) /
                    ((file->counters[CP_RW_SWITCHES] / (2 * aggregator_cnt)) + 1);
            else
                io_ops_this_rw = file->counters[CP_POSIX_WRITES] /
                                 ((file->counters[CP_RW_SWITCHES] / (2 * aggregator_cnt)) + 1);
        }

1017 1018 1019 1020 1021 1022 1023
        /* initialize the rd and wr bandwidth values using total io size and time */
        if (file->fcounters[CP_F_POSIX_READ_TIME])
            rd_bw = file->counters[CP_BYTES_READ] / file->fcounters[CP_F_POSIX_READ_TIME];
        if (file->fcounters[CP_F_POSIX_WRITE_TIME])
            wr_bw = file->counters[CP_BYTES_WRITTEN] / file->fcounters[CP_F_POSIX_WRITE_TIME];
    }

1024 1025 1026 1027 1028
    if (coll_io_ops_this_cycle)
        ind_ops_remaining = ceil((double)ind_io_ops_this_cycle / coll_io_ops_this_cycle);
    else
        ind_ops_remaining = ind_io_ops_this_cycle;

1029 1030
    for (i = 0; i < total_io_ops_this_cycle; i++)
    {
1031
        if (ind_ops_remaining)
1032 1033 1034 1035
        {
            ind_coll = 0;
            tmp_rank = (next_ind_io_rank++) % nprocs;
            io_cnt = 1;
1036 1037
            ind_io_ops_this_cycle--;
            ind_ops_remaining--;
1038 1039 1040 1041 1042 1043 1044 1045 1046
            if (!rw)
                file->counters[CP_INDEP_READS]--;
            else
                file->counters[CP_INDEP_WRITES]--;
        }
        else
        {
            ind_coll = 1;
            tmp_rank = 0;
1047
            coll_io_ops_this_cycle--;
1048 1049 1050
            if (!rw)
            {
                io_cnt = ceil((double)(file->counters[CP_POSIX_READS] -
1051
                              file->counters[CP_INDEP_READS]) / 
1052 1053 1054 1055 1056 1057
                              (file->counters[CP_COLL_READS] / nprocs));
                file->counters[CP_COLL_READS] -= nprocs;
            }
            else
            {
                io_cnt = ceil((double)(file->counters[CP_POSIX_WRITES] -
1058
                              file->counters[CP_INDEP_WRITES]) / 
1059 1060 1061
                              (file->counters[CP_COLL_WRITES] / nprocs));
                file->counters[CP_COLL_WRITES] -= nprocs;
            }
1062 1063 1064 1065 1066 1067 1068

            if (coll_io_ops_this_cycle)
                ind_ops_remaining = ceil((double)ind_io_ops_this_cycle / coll_io_ops_this_cycle);
            else
                ind_ops_remaining = ind_io_ops_this_cycle;

            cur_time = generate_barrier_event(file, 0, cur_time, io_context);
1069 1070 1071 1072
        }

        for (j = 0; j < io_cnt; j++)
        {
1073 1074
            determine_io_params(file, rw, (ind_coll) ? io_cnt - j : ind_io_ops_this_cycle + 1,
                                aggregator_cnt, &io_sz, &io_off);
1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122
            if (!rw)
            {
                /* generate a read event */
                next_io_op.codes_op.op_type = CODES_WK_READ;
                next_io_op.codes_op.u.read.file_id = file->hash;
                next_io_op.codes_op.u.read.size = io_sz;
                next_io_op.codes_op.u.read.offset = io_off;
                next_io_op.start_time = cur_time;

                /* set the end time based on observed bandwidth and io size */
                if (rd_bw == 0.0)
                    io_op_time = 0.0;
                else
                    io_op_time = (io_sz / rd_bw);
                
                next_io_op.end_time = cur_time + io_op_time + meta_op_time;
                file->counters[CP_POSIX_READS]--;
            }
            else
            {
                /* generate a write event */
                next_io_op.codes_op.op_type = CODES_WK_WRITE;
                next_io_op.codes_op.u.write.file_id = file->hash;
                next_io_op.codes_op.u.write.size = io_sz;
                next_io_op.codes_op.u.write.offset = io_off;
                next_io_op.start_time = cur_time;

                /* set the end time based on observed bandwidth and io size */
                if (wr_bw == 0.0)
                    io_op_time = 0.0;
                else
                    io_op_time = (io_sz / wr_bw);

                next_io_op.end_time = cur_time + io_op_time + meta_op_time;
                file->counters[CP_POSIX_WRITES]--;
            }
            psx_rw_ops_remaining--;
            assert(file->counters[CP_POSIX_READS] >= 0);
            assert(file->counters[CP_POSIX_WRITES] >= 0);

            /*  store the i/o event */
            if (tmp_rank == io_context->my_rank)
                darshan_insert_next_io_op(io_context->io_op_dat, &next_io_op);

            if (next_io_op.end_time > max_cur_time)
                max_cur_time = next_io_op.end_time;

            tmp_rank += ranks_per_aggregator;
1123
            if (ind_coll && (tmp_rank >= (ranks_per_aggregator * aggregator_cnt)))
1124 1125 1126 1127 1128 1129 1130
            {
                tmp_rank = 0;
                cur_time = max_cur_time;
            }
        }
        io_ops_this_rw--;

1131 1132 1133 1134 1135 1136 1137 1138 1139 1140
        if (ind_coll)
        {
            total_coll_io_ops--;

            cur_time = max_cur_time;
            if (i != (total_io_ops_this_cycle - 1))
                cur_time += inter_io_delay;
        }
        else
        {
1141 1142
            if (tmp_rank == (nprocs - 1) || (i == (total_io_ops_this_cycle - 1)))
            {
1143 1144
                cur_time = max_cur_time;

1145 1146 1147
                if (i != (total_io_ops_this_cycle - 1))
                    cur_time += inter_io_delay;
            }
1148 1149
        }

1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188
        /* determine whether to toggle between reads and writes */
        if (!io_ops_this_rw && psx_rw_ops_remaining)
        {
            /* toggle the read/write flag */
            rw ^= 1;
            file->counters[CP_RW_SWITCHES] -= aggregator_cnt;

            /* determine how many io ops to do before next rw switch */
            if (!rw)
            {
                if (file->counters[CP_COLL_OPENS])
                    io_ops_this_rw =
                        ((file->counters[CP_COLL_READS] / nprocs) +
                        file->counters[CP_INDEP_READS]) / ((file->counters[CP_RW_SWITCHES] /
                        (2 * aggregator_cnt)) + 1);
                else
                    io_ops_this_rw = file->counters[CP_POSIX_READS] /
                                     ((file->counters[CP_RW_SWITCHES] / (2 * aggregator_cnt)) + 1);
            }
            else
            {
                if (file->counters[CP_COLL_OPENS])
                    io_ops_this_rw =
                        ((file->counters[CP_COLL_WRITES] / nprocs) +
                        file->counters[CP_INDEP_WRITES]) / ((file->counters[CP_RW_SWITCHES] /
                        (2 * aggregator_cnt)) + 1);
                else
                    io_ops_this_rw = file->counters[CP_POSIX_WRITES] /
                                     ((file->counters[CP_RW_SWITCHES] / (2 * aggregator_cnt)) + 1);
            }
        }
    }

    /* reset the static rw flag if this is the last open-close cycle for this file */
    if (file->counters[CP_POSIX_OPENS] <= nprocs)
    {
        rw = -1;
    }

1189
    return cur_time;
1190 1191
}

1192
static void determine_io_params(
1193
    struct darshan_file *file, int write_flag, int64_t io_this_op, int64_t proc_count,
1194 1195 1196 1197
    size_t *io_sz, off_t *io_off)
{
    static uint64_t next_rd_off = 0;
    static uint64_t next_wr_off = 0;
1198 1199 1200 1201 1202 1203 1204
    static int size_bin_ndx = -1;
    static int64_t io_this_size_bin = 0;
    static int64_t rd_common_counts[4];
    static int64_t wr_common_counts[4];
    int64_t *rd_size_bins = &(file->counters[CP_SIZE_READ_0_100]);
    int64_t *wr_size_bins = &(file->counters[CP_SIZE_WRITE_0_100]);
    int64_t *size_bins;
1205 1206 1207 1208
    int64_t *common_accesses = &(file->counters[CP_ACCESS1_ACCESS]); /* 4 common accesses */
    int64_t *common_access_counts = &(file->counters[CP_ACCESS1_COUNT]); /* common access counts */
    int64_t *total_io_size;
    int64_t last_io_byte;
1209
    int look_for_small_bin = 0;
1210 1211 1212 1213 1214 1215 1216
    int i, j = 0;
    int64_t bin_min_size[10] = { 0, 100, 1024, 10 * 1024, 100 * 1024, 1024 * 1024, 4 * 1024 * 1024,
                                 10 * 1024 * 1024, 100 * 1024 * 1024, 1024 * 1024 * 1024 };
    int64_t bin_def_size[10] = { 40, 512, 4 * 1024, 60 * 1024, 512 * 1024, 2 * 1024 * 1024,
                                 6 * 1024 * 1024, 40 * 1024 * 1024, 400 * 1024 * 1024,
                                 1 * 1024 * 1024 * 1024 };

1217 1218 1219
    assert(io_this_op);

    if (size_bin_ndx == -1)
1220 1221 1222
    {
        for (i = 0; i < 4; i++)
        {
1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248
            for (j = 0; j < 10; j++)
            {
                if (IO_IS_IN_SIZE_BIN_RANGE(common_accesses[i], j, bin_min_size))
                {
                    if (rd_size_bins[j] && wr_size_bins[j])
                    {
                        rd_common_counts[i] = MIN(common_access_counts[i] / 2, rd_size_bins[j]);
                        wr_common_counts[i] = common_access_counts[i] - rd_common_counts[i];
                    }
                    else if (rd_size_bins[j])
                    {
                        rd_common_counts[i] = common_access_counts[i];
                        wr_common_counts[i] = 0;
                    }
                    else if (wr_size_bins[j])
                    {
                        rd_common_counts[i] = 0;
                        wr_common_counts[i] = common_access_counts[i];
                    }
                    else
                    {
                        rd_common_counts[i] = wr_common_counts[i] = 0;
                    }
                    break;
                }
            }
1249 1250 1251 1252 1253 1254 1255 1256
        }
    }

    /* assign data values depending on whether the operation is a read or write */
    if (write_flag)
    {
        total_io_size = &(file->counters[CP_BYTES_WRITTEN]);
        last_io_byte = file->counters[CP_MAX_BYTE_WRITTEN];
1257 1258
        size_bins = wr_size_bins;
        common_access_counts = wr_common_counts;
1259 1260 1261 1262 1263
    }
    else
    {
        total_io_size = &(file->counters[CP_BYTES_READ]);
        last_io_byte = file->counters[CP_MAX_BYTE_READ];
1264 1265
        size_bins = rd_size_bins;
        common_access_counts = rd_common_counts;
1266 1267
    }

1268
    if (!io_this_size_bin)
1269
    {
1270
        if (io_this_op < proc_count)
1271
        {
1272 1273
            look_for_small_bin = 1;
            for (i = 0; i < 10; i++)
1274
            {
1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287
                if (size_bins[i] % proc_count)
                {
                    if (!io_this_size_bin)
                    {
                        size_bin_ndx = i;
                        io_this_size_bin = MIN(size_bins[i] % proc_count, io_this_op);
                    }
                    else if ((size_bins[i] % proc_count) < io_this_size_bin)
                    {
                        size_bin_ndx = i;
                        io_this_size_bin = size_bins[i] % proc_count;
                    }
                }
1288 1289
            }
        }
1290
        else
1291
        {
1292
            for (i = 0; i < 10; i++)
1293
            {
1294
                if (size_bins[i] && ((size_bins[i] % proc_count) == 0))
1295
                {
1296 1297
                    if (!io_this_size_bin ||
                        (io_this_size_bin && (size_bins[i] > size_bins[size_bin_ndx])))
1298
                    {
1299 1300
                        size_bin_ndx = i;
                        io_this_size_bin = proc_count;
1301 1302
                    }
                }
1303 1304 1305 1306 1307 1308 1309 1310
            }
        }

        if (!io_this_size_bin)
        {
            for (i = 0; i < 10; i++)
            {
                if (size_bins[i])
1311
                {
1312 1313 1314
                    size_bin_ndx = i;
                    io_this_size_bin = size_bins[i];
                    if (io_this_size_bin > io_this_op)
1315
                    {
1316
                        io_this_size_bin = io_this_op;
1317
                    }
1318
                    break;
1319 1320 1321 1322
                }
            }
        }
    }
1323 1324 1325

    *io_sz = 0;
    if (*total_io_size > 0)
1326
    {
1327 1328 1329 1330 1331 1332
        if ((write_flag && (file->counters[CP_POSIX_WRITES] == 1)) ||
            (!write_flag && (file->counters[CP_POSIX_READS] == 1)))
        {
            *io_sz = *total_io_size;
        }
        else
1333
        {
1334
            /* try to assign a common access first (intelligently) */
1335 1336
            for (j = 0; j < 4; j++)
            {
1337 1338
                if (common_access_counts[j] &&
                    IO_IS_IN_SIZE_BIN_RANGE(common_accesses[j], size_bin_ndx, bin_min_size))
1339
                {
1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354
                    if (look_for_small_bin)
                    {
                        if (common_access_counts[j] == io_this_op)
                        {
                            *io_sz = common_accesses[j];
                            common_access_counts[j]--;
                            break;
                        }
                    }
                    else
                    {
                        *io_sz = common_accesses[j];
                        common_access_counts[j]--;
                        break;
                    }
1355 1356
                }

1357
                if ((j == 3) && look_for_small_bin)
1358
                {
1359 1360
                    j = 0;
                    look_for_small_bin = 0;
1361 1362
                }
            }
1363 1364 1365 1366

            /* if no common accesses left, then assign default size for this bin */
            if (*io_sz == 0)
                *io_sz = bin_def_size[size_bin_ndx];
1367 1368 1369 1370 1371
        }
        assert(*io_sz);
    }

    *total_io_size -= *io_sz;
1372 1373
    size_bins[size_bin_ndx]--;
    io_this_size_bin--;
1374 1375 1376 1377 1378 1379 1380 1381 1382 1383

    /* next, determine the offset to use */

    /*  for now we just assign a random offset that makes sure not to write past the recorded
     *  last byte written in the file.
     */
    if (*io_sz == 0)
    {
        *io_off = last_io_byte + 1;
    }
1384
    else
1385
    {
1386 1387 1388 1389
        if (write_flag)
        {
            if ((next_wr_off + *io_sz) > (last_io_byte + 1))
                next_wr_off = 0;
1390

1391 1392 1393 1394 1395 1396 1397
            *io_off = next_wr_off;
            next_wr_off += *io_sz;
        }
        else
        {
            if ((next_rd_off + *io_sz) > (last_io_byte + 1))
                next_rd_off = 0;
1398

1399 1400 1401
            *io_off = next_rd_off;
            next_rd_off += *io_sz;
        }
1402 1403 1404 1405 1406
    }

    /* reset static variable if this is the last i/o op for this file */
    if ((file->counters[CP_POSIX_READS] + file->counters[CP_POSIX_WRITES]) == 1)
    {
1407 1408
        io_this_size_bin = 0;
        size_bin_ndx = -1;
1409 1410 1411 1412 1413 1414 1415 1416 1417
        next_rd_off = next_wr_off = 0;
    }

    return;
}

/* calculate the simulated "delay" between different i/o events using delay info
 * from the file counters */
static void calc_io_delays(
1418
    struct darshan_file *file, int64_t num_opens, int64_t num_io_ops, double total_delay,
1419 1420 1421 1422 1423 1424 1425
    double *first_io_delay, double *close_delay, double *inter_open_delay, double *inter_io_delay)
{
    double first_io_time, last_io_time;
    double first_io_pct, close_pct, inter_open_pct, inter_io_pct;
    double total_delay_pct;
    double tmp_inter_io_pct, tmp_inter_open_pct;

1426
    if (total_delay > 0.0)
1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449
    {
        /* determine the time of the first io operation */
        if (!file->fcounters[CP_F_WRITE_START_TIMESTAMP])
            first_io_time = file->fcounters[CP_F_READ_START_TIMESTAMP];
        else if (!file->fcounters[CP_F_READ_START_TIMESTAMP])
            first_io_time = file->fcounters[CP_F_WRITE_START_TIMESTAMP];
        else if (file->fcounters[CP_F_READ_START_TIMESTAMP] <
                 file->fcounters[CP_F_WRITE_START_TIMESTAMP])
            first_io_time = file->fcounters[CP_F_READ_START_TIMESTAMP];
        else
            first_io_time = file->fcounters[CP_F_WRITE_START_TIMESTAMP];

        /* determine the time of the last io operation */
        if (file->fcounters[CP_F_READ_END_TIMESTAMP] > file->fcounters[CP_F_WRITE_END_TIMESTAMP])
            last_io_time = file->fcounters[CP_F_READ_END_TIMESTAMP];
        else
            last_io_time = file->fcounters[CP_F_WRITE_END_TIMESTAMP];

        /* no delay contribution for inter-open delay if there is only a single open */
        if (num_opens > 1)
            inter_open_pct = DEF_INTER_CYC_DELAY_PCT;

        /* no delay contribution for inter-io delay if there is one or less io op */
1450
        if ((num_io_ops - num_opens) > 0)
1451 1452 1453 1454 1455
            inter_io_pct = DEF_INTER_IO_DELAY_PCT;

        /* determine delay contribution for first io and close delays */
        if (first_io_time != 0.0)
        {
1456 1457 1458 1459
            first_io_pct = (first_io_time - file->fcounters[CP_F_OPEN_TIMESTAMP]) *
                           (num_opens / total_delay);
            close_pct = (file->fcounters[CP_F_CLOSE_TIMESTAMP] - last_io_time) *
                        (num_opens / total_delay);
1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486
        }
        else
        {
            first_io_pct = 0.0;
            close_pct = 1 - inter_open_pct;
        }

        /* adjust per open delay percentages using a simple heuristic */
        total_delay_pct = inter_open_pct + inter_io_pct + first_io_pct + close_pct;
        if ((total_delay_pct < 1) && (inter_open_pct || inter_io_pct))
        {
            /* only adjust inter-open and inter-io delays if we underestimate */
            tmp_inter_open_pct = (inter_open_pct / (inter_open_pct + inter_io_pct)) *
                                 (1 - first_io_pct - close_pct);
            tmp_inter_io_pct = (inter_io_pct / (inter_open_pct + inter_io_pct)) *
                               (1 - first_io_pct - close_pct);
            inter_open_pct = tmp_inter_open_pct;
            inter_io_pct = tmp_inter_io_pct;
        }
        else
        {
            inter_open_pct += (inter_open_pct / total_delay_pct) * (1 - total_delay_pct);
            inter_io_pct += (inter_io_pct / total_delay_pct) * (1 - total_delay_pct);
            first_io_pct += (first_io_pct / total_delay_pct) * (1 - total_delay_pct);
            close_pct += (close_pct / total_delay_pct) * (1 - total_delay_pct);
        }

1487 1488
        *first_io_delay = (first_io_pct * total_delay) / num_opens;
        *close_delay = (close_pct * total_delay) / num_opens;
1489 1490

        if (num_opens > 1)
1491
            *inter_open_delay = (inter_open_pct * total_delay) / (num_opens - 1);
1492
        if ((num_io_ops - num_opens) > 0)
1493
            *inter_io_delay = (inter_io_pct * total_delay) / (num_io_ops - num_opens);
1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558
    }

    return;
}

/* check to make sure file stats are valid and properly formatted */
static void file_sanity_check(
    struct darshan_file *file, struct darshan_job *job)
{
    assert(file->counters[CP_POSIX_OPENS] != -1);
    assert(file->fcounters[CP_F_OPEN_TIMESTAMP] != -1);
    assert(file->counters[CP_COLL_OPENS] != -1);
    assert