add dynamic progress timeout to margo

src/margo-timer.c

@@ -177,6 +177,35 @@ void margo_check_timers(
     return;
 }
 
+/* returns 0 and sets 'next_timer_exp' if the timer instance
+ * has timers queued up, -1 otherwise
+ */
+int margo_timer_get_next_expiration(
+    margo_instance_id mid,
+    double *next_timer_exp)
+{
+    struct margo_timer_instance *timer_inst;
+    double now = ABT_get_wtime();
+    int ret;
+
+    timer_inst = margo_get_timer_instance(mid);
+    assert(timer_inst);
+
+    ABT_mutex_lock(timer_inst->mutex);
+    if(timer_inst->queue_head)
+    {
+        *next_timer_exp = timer_inst->queue_head->expiration - now;
+        ret = 0;
+    }
+    else
+    {
+        ret = -1;
+    }
+    ABT_mutex_unlock(timer_inst->mutex);
+
+    return(ret);
+}
+
 static struct margo_timer_instance *margo_get_timer_instance(
     margo_instance_id mid)
 {

src/margo-timer.h

@@ -69,6 +69,17 @@ void margo_timer_destroy(
 void margo_check_timers(
     margo_instance_id mid);
 
+/**
+ * Determines the amount of time (in seconds) until the next timer
+ * is set to expire
+ * @param [in] mid Margo instance
+ * @param [out] time until next timer expiration
+ * @returns 0 when there is a queued timer which will expire, -1 otherwise
+ */
+int margo_timer_get_next_expiration(
+    margo_instance_id mid,
+    double *next_timer_exp);
+
 #ifdef __cplusplus
 }
 #endif

src/margo.c

@@ -22,6 +22,8 @@
  */
 #include <mercury_core.h>
 
+#define MERCURY_PROGRESS_TIMEOUT_UB 100 /* 100 milliseconds */
+
 struct margo_instance
 {
     /* provided by caller */
@@ -189,6 +191,8 @@ static void hg_progress_fn(void* foo)
     unsigned int actual_count;
     struct margo_instance *mid = (struct margo_instance *)foo;
     size_t size;
+    unsigned int hg_progress_timeout = MERCURY_PROGRESS_TIMEOUT_UB;
+    double next_timer_exp;
 
     while(!mid->hg_progress_shutdown_flag)
     {
@@ -215,7 +219,25 @@ static void hg_progress_fn(void* foo)
             else
             {
                 ABT_mutex_unlock(mid->finalize_mutex);
-                HG_Progress(mid->hg_context, 100);
+
+                ret = margo_timer_get_next_expiration(mid, &next_timer_exp);
+                if(ret == 0)
+                {
+                    /* there is a queued timer, don't block long enough
+                     * to keep this timer waiting
+                     */
+                    if(next_timer_exp >= 0.0)
+                    {
+                        next_timer_exp *= 1000; /* convert to milliseconds */
+                        if(next_timer_exp < MERCURY_PROGRESS_TIMEOUT_UB)
+                            hg_progress_timeout = (unsigned int)next_timer_exp;
+                    }
+                    else
+                    {
+                        hg_progress_timeout = 0;
+                    }
+                }
+                HG_Progress(mid->hg_context, hg_progress_timeout);
             }
         }