From 3c6430d7b2a15133e467a3a4e04a3a8a012d09f3 Mon Sep 17 00:00:00 2001
From: Leandro Lucarella <llucax@gmail.com>
Date: Sun, 14 Nov 2010 18:52:44 -0300
Subject: [PATCH] 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.
---
 bench.sh | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100755 bench.sh

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 $cpu_list | tr ' ' ,` "$@"
+
-- 
2.43.0