tools/testing/selftests/rcutorture/bin/cpus2use.sh

   1 #!/bin/bash
   2 # SPDX-License-Identifier: GPL-2.0+
   3 #
   4 # Get an estimate of how CPU-hoggy to be.
   5 #
   6 # Usage: cpus2use.sh
   7 #
   8 # Copyright (C) IBM Corporation, 2013
   9 #
  10 # Authors: Paul E. McKenney <paulmck@linux.ibm.com>
  11
  12 if test -n "$TORTURE_ALLOTED_CPUS"
  13 then
  14         echo $TORTURE_ALLOTED_CPUS
  15         exit 0
  16 fi
  17 ncpus=`grep '^processor' /proc/cpuinfo | wc -l`
  18 idlecpus=`mpstat | tail -1 | \
  19         awk -v ncpus=$ncpus '{ print ncpus * ($7 + $NF) / 100 }'`
  20 awk -v ncpus=$ncpus -v idlecpus=$idlecpus < /dev/null '
  21 BEGIN {
  22         cpus2use = idlecpus;
  23         if (cpus2use < 1)
  24                 cpus2use = 1;
  25         if (cpus2use < ncpus / 10)
  26                 cpus2use = ncpus / 10;
  27         if (cpus2use == int(cpus2use))
  28                 cpus2use = int(cpus2use)
  29         else
  30                 cpus2use = int(cpus2use) + 1
  31         print cpus2use;
  32 }'
  33