Commit 8d57923b authored by Swann Perarnau's avatar Swann Perarnau
Browse files

Merge branch 'power_policy_interface' into 'master'

Merge Power policy interface

Closes #11

See merge request !18
parents a2274c7f 791a82db
Pipeline #3656 failed with stages
......@@ -50,6 +50,8 @@ class ContainerManager(object):
environ['AC_APP_NAME'] =
environ['AC_METADATA_URL'] = "localhost""run: environ: %r", environ)
# TODO: Application library to load must be set during configuration
applicationpreloadlibrary = '.so'
# create container
container_name = request['uuid']
......@@ -74,6 +76,12 @@ class ContainerManager(object):
if in ["1", "True"]:
if hasattr(, 'powerpolicy'):
if hasattr(, 'enabled'):
if in ["1", "True"]:
if != "NONE":
environ['LD_PRELOAD'] = applicationpreloadlibrary
process = self.nodeos.execute(container_name, argv, environ)
""" DutyCycle Module:
This module contains functions to set duty cyle of each cpu in intervals
of 6.25% min = 6.25% max(default) = 100%
Value - Duty Cycle
0 - 100.0%
1 - 6.25%
2 - 12.5%
3 - 18.75%
15 - 93.75%
16 - 100.0%
There are also functions to reset the duty cycle of a cpu and check the
current value of duty cycle
import msr
class DutyCycle:
def __init__(self):
self.register = 0x19A
self.msr = msr.Msr()
# set duty cycle of a cpu
def set(self, cpu, value):
if 0 < value < 16:
self.msr.write(cpu, self.register, 16 + value)
self.msr.write(cpu, self.register, 0)
# reset duty cycle of a cpu
def reset(self, cpu):
self.msr.write(cpu, self.register, 0)
# check current duty cycle value
def check(self, cpu):
return, self.register)
""" Msr Module:
This module provides the interfaces to read and write msr through msr_safe
kernel module.
Note: msr_safe kernel module needs to be installed on your machine for this
module to work. To run with root privileges change 'msr_safe' in
get_file_name() function to 'msr'.
import os
import sys
import errno
import struct
class Msr:
# get msr file name for the cpu
def get_file_name(self, cpu):
return '/dev/cpu/%d/msr_safe' % cpu
# open msr file with correct privileges
def file_open(self, filename, privilege):
if privilege == 'r':
fd =, os.O_RDONLY)
elif privilege == 'w':
fd =, os.O_WRONLY)
except OSError as e:
if e.errno == errno.ENXIO:
sys.exit('file_open: No such device or address ' + filename)
elif e.errno == errno.EIO:
sys.exit('file_open: I/O error ' + filename)
elif e.errno == errno.EACCES:
sys.exit('file_open: Permission denied ' + filename)
sys.exit('file_open: Error ' + filename)
return fd
# read a msr
def read(self, cpu, register):
msrfile = self.get_file_name(cpu)
fd = self.file_open(msrfile, 'r')
os.lseek(fd, int(register), os.SEEK_SET)
""" read and handle binary data from msr file """
value = struct.unpack('Q',, 8))[0]
except OSError as e:
if e.errno == errno.EIO:
sys.exit('read: I/O error ' + msrfile)
elif e.errno == errno.EACCES:
sys.exit('read: Permission denied ' + msrfile)
sys.exit('read: Error ' + msrfile)
return value
# write a msr
def write(self, cpu, register, value):
msrfile = self.get_file_name(cpu)
fd = self.file_open(msrfile, 'w')
os.lseek(fd, int(register), os.SEEK_SET)
""" write binary data to msr file """
os.write(fd, struct.pack('Q', value))
except OSError as e:
if e.errno == errno.EIO:
sys.exit('write: I/O error ' + msrfile)
elif e.errno == errno.EACCES:
sys.exit('write: Permission denied ' + msrfile)
sys.exit('write: Error ' + msrfile)
return value
""" DDCMPolicy Module:
This module contains the Dynamic Duty Cycle Modulation (DDCM) based policy
aimed at mitigating workload imbalance in parallel applications that use
barrier synchronizations. It reduces duty cycle of cpus not on the critical
path of execution thereby reducing energy with little or no adverse impact
on performance.
This implementation specifically targets Intel architecture.
Please check your architecture specification for supported power control
mechanisms and other information.
Additional information:
1. Bhalachandra, Sridutt, Allan Porterfield, and Jan F. Prins. "Using
dynamic duty cycle modulation to improve energy efficiency in high
performance computing." In Parallel and Distributed Processing Symposium
Workshop (IPDPSW), 2015 IEEE International, pp. 911-918. IEEE, 2015.
2. Porterfield, Allan, Rob Fowler, Sridutt Bhalachandra, Barry Rountree,
Diptorup Deb, and Rob Lewis. "Application runtime variability and power
optimization for exascale computers." In Proceedings of the 5th
International Workshop on Runtime and Operating Systems for Supercomputers,
p. 3. ACM, 2015.
import math
import coolr
import coolr.dutycycle
class DDCMPolicy:
""" Contains cpu-specific DDCM based power policy """
def __init__(self, maxlevel=16, minlevel=1):
self.maxdclevel = maxlevel
self.mindclevel = minlevel
# Relaxation factor
self.relaxation = 1
self.ddcmpolicyset = 0
self.ddcmpolicyreset = 0
self.dc = coolr.dutycycle.DutyCycle()
def print_stats(self, resetflag=False):
print('DDCM Policy: DDCMPolicySets %d DDCMPolicyResets %d' %
(self.ddcmpolicyset, self.ddcmpolicyreset))
if resetflag:
self.ddcmpolicyset = 0
self.ddcmpolicyreset = 0
def execute(self, cpu, currentdclevel, computetime, totalphasetime):
# Compute work done by cpu during current phase
work = computetime / totalphasetime
# Compute effective work based on current duty cycle(dc) level
effectivework = work * self.maxdclevel / currentdclevel
# Compute effective slow down in current phase
effectiveslowdown = work * self.mindclevel / currentdclevel
# Decrease or keep constant dc level in the next phase if the effective
# work done is equal or less than 1.0
if effectivework <= 1.0:
self.ddcmpolicyset += 1
# Compute by how many levels dc needs to decrease
dcreduction = math.floor(effectivework / 0.0625) - 15
# Compute new dc level for next phase
if -14 < dcreduction < 0:
# Note that dcreduction is a negative value
newdclevel = currentdclevel + dcreduction + self.relaxation
elif dcreduction < -13:
# Empirical observation shows reducing dc below 18.75% leads to
# excessive slowdown
newdclevel = currentdclevel - 13
# If reduction required is 0
newdclevel = currentdclevel
# Check if new dc level computed is not less than whats permissible
if newdclevel < self.mindclevel:
newdclevel = self.maxdclevel
# If there was a slowdown in the last phase, then increase the duty
# cycle level corresponding to the slowdown
self.ddcmpolicyreset += 1
# Compute by how many levels dc needs to increase
dcincrease = math.floor(effectiveslowdown / 0.0625)
newdclevel = currentdclevel + dcincrease
# Check if new dc level computed is not greater than whats
# permissible
if newdclevel > self.maxdclevel:
newdclevel = self.maxdclevel
# Set the duty cycle of cpu to the new value computed
self.dc.set(cpu, newdclevel)
return newdclevel
""" Power Policy Module:
This module provides the interfaces that enable use of policies to control
processor power using controls available in the processor.
E.g. Dynamic Duty Cycle Modulation (DDCM), Dynamic Voltage
and Frequency Scaling (DVFS) and Power capping
The policies target problems like workload imbalance, memory saturation
seen very often in parallel applications.
To mitigate workload imbalance the policies adapt core frequencies to
workload characteristics through use of core-specific power controls.
The user can choose from three policies - DDCM, DVFS and a combination of
DVFS and DDCM to mitiage workload imbalance in parallel applications that
use barrier synchronizations.
The effective frequency of cpus not on the critical path of execution is
reduced thereby lowering energy with little or no adverse impact on
Additional information:
Bhalachandra, Sridutt, Allan Porterfield, Stephen L. Olivier, and Jan F.
Prins. "An adaptive core-specific runtime for energy efficiency." In 2017
IEEE International Parallel and Distributed Processing Symposium (IPDPS),
pp. 947-956. 2017.
Note: Power controls (DVFS, DDCM and power capping) needs to be enabled
before using these interfaces. Please check your architecture specification
for supported power contols and related information.
import ddcmpolicy
class PowerPolicyManager:
""" Used for power policy application """
def __init__(self, ncpus=0, policy='NONE', damper=0.1, slowdown=1.1):
self.policy = policy
self.damper = damper
self.slowdown = slowdown
# TODO: Need to set this based on container configuration
self.ncpus = ncpus
# Intiliaze all power interfaces
self.ddcmpolicy = ddcmpolicy.DDCMPolicy()
# Power levels
self.maxdclevel = self.ddcmpolicy.maxdclevel
# TODO: Need to set this value when DVFS policies are added
self.maxfreqlevel = -1
# TODO: Need to only allow power changes to cpus in container
self.dclevel = dict.fromkeys(range(0, self.ncpus), self.maxdclevel)
self.freqlevel = dict.fromkeys(range(0, self.ncpus), self.maxfreqlevel)
# Book-keeping
self.damperexits = 0
self.slowdownexits = 0
self.prevtolalphasetime = 10000.0 # Random large value
def run_policy(self, cpu, startcompute, endcompute, startbarrier,
# Select and invoke appropriate power policy
# TODO: Need to add a better policy selection logic in addition to user
# specified
ret, value = self.invoke_policy(cpu, self.policy, self.dclevel[cpu],
self.freqlevel[cpu], startcompute,
endcompute, startbarrier, endbarrier)
if self.policy == 'DDCM' and ret in ['DDCM', 'SLOWDOWN']:
self.dclevel[cpu] = value
def invoke_policy(self, cpu, policy, dclevel, freqlevel, startcompute,
endcompute, startbarrier, endbarrier):
# Run with no policy
if policy == "NONE":
return 'NONE', -1
# Calculate time spent in computation, barrier in current phase along
# with total phase time
computetime = endcompute - startcompute
barriertime = endbarrier - startbarrier
totalphasetime = computetime + barriertime
# If the current phase length is less than the damper value, then do
# not use policy. This avoids use of policy during startup operation
# insignificant phases
if totalphasetime < self.damper:
self.damperexits += 1
return 'DAMPER', -1
# Reset value for next phase
self.prevtolalphasetime = totalphasetime
# If the current phase has slowed down beyond the threshold set, then
# reset power. This helps correct error in policy application or acts
# as a rudimentary way to detect phase change
if(dclevel < self.ddcmpolicy.maxdclevel and totalphasetime >
self.slowdown * self.prevtolalphasetime):
newdclevel = self.ddcmpolicy.maxdclevel
return 'SLOWDOWN', newdclevel
# Invoke the correct policy based on operation module
if policy == "DDCM":
newdclevel = self.ddcmpolicy.execute(cpu, dclevel, computetime,
# TODO: Add DVFS and Combined policies
return 'DDCM', newdclevel
def print_policy_stats(self, resetflag=False):
# Get statistics for policy run
print('PowerPolicyManager: DamperExits %d SlowdownExits %d' %
(self.damperexits, self.slowdownexits))
if resetflag:
self.damperexits = 0
self.slowdownexits = 0
def power_reset(self, cpu):
# Reset all power controls
self.dclevel[cpu] = self.maxdclevel
def power_check(self, cpu):
# Check status of all power controls
return self.ddcmpolicy.dc.check(cpu)
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