From ce781a183272fe835c318dc5affb8d64558a4e2b Mon Sep 17 00:00:00 2001
From: cody burkard <cody@onlab.us>
Date: Thu, 21 Aug 2014 17:39:59 -0700
Subject: [PATCH] use cgroups to calculate percentage of cpu used
---
mininet/net.py | 53 +++++++++++++++++++++++++++++---------------------
1 file changed, 31 insertions(+), 22 deletions(-)
diff --git a/mininet/net.py b/mininet/net.py
index 8a6acdcc..0ef0a043 100755
--- a/mininet/net.py
+++ b/mininet/net.py
@@ -94,6 +94,7 @@
import copy
from time import sleep
from itertools import chain, groupby
+from math import ceil
from mininet.cli import CLI
from mininet.log import info, error, debug, output, warn
@@ -726,33 +727,41 @@ def runCpuLimitTest( self, cpu, duration=5 ):
duration: test duration in seconds
returns a single list of measured CPU fractions as floats.
"""
+ cores = int( quietRun( 'nproc' ) )
pct = cpu * 100
- info('*** Testing CPU %.0f%% bandwidth limit\n' % pct)
+ info( '*** Testing CPU %.0f%% bandwidth limit\n' % pct )
hosts = self.hosts
+ cores = int( quietRun( 'nproc' ) )
+ # number of processes to run a while loop on per host
+ num_procs = int( ceil( cores * cpu ) )
+ pids = {}
for h in hosts:
- h.cmd( 'while true; do a=1; done &' )
- pids = [h.cmd( 'echo $!' ).strip() for h in hosts]
- pids_str = ",".join(["%s" % pid for pid in pids])
- cmd = 'ps -p %s -o pid,%%cpu,args' % pids_str
- # It's a shame that this is what pylint prefers
- outputs = []
- for _ in range( duration ):
+ pids[ h ] = []
+ for _core in range( num_procs ):
+ h.cmd( 'while true; do a=1; done &' )
+ pids[ h ].append( h.cmd( 'echo $!' ).strip() )
+ outputs = {}
+ time = {}
+ # get the initial cpu time for each host
+ for host in hosts:
+ outputs[ host ] = []
+ with open( '/sys/fs/cgroup/cpuacct/%s/cpuacct.usage' % host, 'r' ) as f:
+ time[ host ] = float( f.read() )
+ for _ in range( 5 ):
sleep( 1 )
- outputs.append( quietRun( cmd ).strip() )
- for h in hosts:
- h.cmd( 'kill $!' )
+ for host in hosts:
+ with open( '/sys/fs/cgroup/cpuacct/%s/cpuacct.usage' % host, 'r' ) as f:
+ readTime = float( f.read() )
+ outputs[ host ].append( ( ( readTime - time[ host ] )
+ / 1000000000 ) / cores * 100 )
+ time[ host ] = readTime
+ for h, pids in pids.items():
+ for pid in pids:
+ h.cmd( 'kill -9 %s' % pid )
cpu_fractions = []
- for test_output in outputs:
- # Split by line. Ignore first line, which looks like this:
- # PID %CPU COMMAND\n
- for line in test_output.split('\n')[1:]:
- r = r'\d+\s*(\d+\.\d+)'
- m = re.search( r, line )
- if m is None:
- error( '*** Error: could not extract CPU fraction: %s\n' %
- line )
- return None
- cpu_fractions.append( float( m.group( 1 ) ) )
+ for _host, outputs in outputs.items():
+ for pct in outputs:
+ cpu_fractions.append( pct )
output( '*** Results: %s\n' % cpu_fractions )
return cpu_fractions
--
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