From: Leandro Lucarella <llucax@gmail.com>
Date: Sun, 14 Nov 2010 21:52:44 +0000 (-0300)
Subject: Add a helper script to improve accuracy when benchmarking
X-Git-Url: https://git.llucax.com/software/dgc/dgcbench.git/commitdiff_plain/3c6430d7b2a15133e467a3a4e04a3a8a012d09f3

Add a helper script to improve accuracy when benchmarking

This script put the CPU in 'performance' mode to avoid distortion in the
results because of CPU frequency changes. It also gives the process
maximum CPU time and I/O priority using nice and ionice respectively.
Finally, it only uses the number of CPUs specifiend in the CPUS
environment variable to run the program.

The scripts is used like this:

	CPUS=2 ./bench.sh some_prog --some-args

This runs "some_prog" passing "--some-args" as arguments, using 2 CPUs.
---

diff --git a/bench.sh b/bench.sh
new file mode 100755
index 0000000..81b819b
--- /dev/null
+++ b/bench.sh
@@ -0,0 +1,25 @@
+#!/bin/sh
+set -e
+
+export CPUS="$1"
+shift
+
+cpu_list=`seq 0 $(($CPUS-1))`
+
+bye() {
+	for n in $cpu_list
+	do
+		cpufreq-set -c $n -g ondemand
+	done
+}
+
+trap bye EXIT
+trap bye INT
+
+for n in $cpu_list
+do
+	cpufreq-set -c $n -g performance
+done
+
+nice -n-19 ionice -c 1 taskset -c `echo $cpu_list | tr ' ' ,` "$@"
+