perf, H/W counters - ESX hosted VM

From: David Ahern
Date: Fri May 27 2011 - 15:34:03 EST



Has anyone successfully used perf within an ESX VM? dmesg shows a PMU is
discovered:

dmesg | grep -i performance
Performance Events: Nehalem/Corei7 events, Intel PMU driver.

yet data from it is nonsensical:

perf stat -v -- /tmp/a

task-clock-msecs: 20593318 20593318 20593318
context-switches: 2 20593318 20593318
CPU-migrations: 0 20593318 20593318
page-faults: 387 20593318 20593318
cycles: 10737418235 20593318 20593318
instructions: 10737418235 20593318 20593318
cache-references: 10737418235 20593318 20593318
cache-misses: 10737418235 20593318 20593318

Performance counter stats for '/tmp/a':

20.593318 task-clock-msecs # 0.988 CPUs
2 context-switches # 0.000 M/sec
0 CPU-migrations # 0.000 M/sec
387 page-faults # 0.019 M/sec
10737418235 cycles # 521403.022 M/sec
10737418235 instructions # 1.000 IPC
10737418235 cache-references # 521403.022 M/sec
10737418235 cache-misses # 521403.022 M/sec

0.020837863 seconds time elapsed

David

/tmp/a -- a step above 'sleep 1'

#!/bin/sh

declare -i i=0;
declare -i sum=0;
while [ $i -lt 1000 ]
do
sum=$((sum + i))
i=$((i+1))
done
echo "sum $sum"
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