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 $TORTURE_ALLOTED_CPUS
  15         exit 0
  16 fi
  17 ncpus=`grep '^processor' /proc/cpuinfo | wc -l`
  18 if mpstat -V > /dev/null 2>&1
  19 then
  20         idlecpus=`mpstat | tail -1 | \
  21                 awk -v ncpus=$ncpus '{ print ncpus * ($7 + $NF) / 100 }'`
  22 else
  23         # No mpstat command, so use all available CPUs.
  24         echo The mpstat command is not available, so greedily using all CPUs.
  25         idlecpus=$ncpus
  26 fi
  27 awk -v ncpus=$ncpus -v idlecpus=$idlecpus < /dev/null '
  28 BEGIN {
  29         cpus2use = idlecpus;
  30         if (cpus2use < 1)
  31                 cpus2use = 1;
  32         if (cpus2use < ncpus / 10)
  33                 cpus2use = ncpus / 10;
  34         if (cpus2use == int(cpus2use))
  35                 cpus2use = int(cpus2use)
  36         else
  37                 cpus2use = int(cpus2use) + 1
  38         print cpus2use;
  39 }'
  40