1#!/bin/bash
2#
3# Get an estimate of how CPU-hoggy to be.
4#
5# Usage: cpus2use.sh
6#
7# This program is free software; you can redistribute it and/or modify
8# it under the terms of the GNU General Public License as published by
9# the Free Software Foundation; either version 2 of the License, or
10# (at your option) any later version.
11#
12# This program is distributed in the hope that it will be useful,
13# but WITHOUT ANY WARRANTY; without even the implied warranty of
14# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15# GNU General Public License for more details.
16#
17# You should have received a copy of the GNU General Public License
18# along with this program; if not, you can access it online at
19# http://www.gnu.org/licenses/gpl-2.0.html.
20#
21# Copyright (C) IBM Corporation, 2013
22#
23# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
24
25ncpus=`grep '^processor' /proc/cpuinfo | wc -l`
26idlecpus=`mpstat | tail -1 | \
27	awk -v ncpus=$ncpus '{ print ncpus * ($7 + $NF) / 100 }'`
28awk -v ncpus=$ncpus -v idlecpus=$idlecpus < /dev/null '
29BEGIN {
30	cpus2use = idlecpus;
31	if (cpus2use < 1)
32		cpus2use = 1;
33	if (cpus2use < ncpus / 10)
34		cpus2use = ncpus / 10;
35	if (cpus2use == int(cpus2use))
36		cpus2use = int(cpus2use)
37	else
38		cpus2use = int(cpus2use) + 1
39	print cpus2use;
40}'
41
42