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#!/bin/bash
# Variable decided outcome of test, this is the minimum isolation we need.
MIN_ISOLATION=10
RESULT="PASS"
if [ $2 ]; then
MIN_ISOLATION=$2
fi
# $1 is the number of samples required of isolation time, by default 1
if [ "$1" = "-h" -o "$1" = "--help" ]; then
echo "Usage: $0 <number of samples to take> <Min Isolation Time Expected>"
exit
elif [ $1 ]; then
sample_count=$1
else
sample_count=1
fi
# ROUTINES
debug_script=1
isdebug() {
if [ $debug_script -eq 1 ]; then
$*
fi
}
# routine to get tick count
get_tick_count() { cat /proc/interrupts | grep arch_timer | grep 30 | sed 's/\s\+/ /g' | cut -d' ' -f4 ; }
#For testing script on: x86
#get_tick_count() { cat /proc/interrupts | grep NMI | sed 's/\s\+/ /g' | cut -d' ' -f4 ; }
# routine to get CPU isolation time
get_isolation_duration() {
isdebug echo ""
isdebug echo ""
isdebug echo "Capture Isolation time"
isdebug echo "----------------------"
isdebug echo "No. of samples requested:" $sample_count", min isolation required:" $MIN_ISOLATION
isdebug echo ""
new_count=$(get_tick_count)
isdebug echo "initial count: " $new_count
x=0
while [ $x -lt $sample_count ]
do
let x=x+1
old_count=$new_count
while [ $new_count -eq $old_count ]
do
new_count=$(get_tick_count)
done
isdebug echo "count locked: " $new_count
old_count=$new_count;
# Get time as a UNIX timestamp (seconds elapsed since Jan 1, 1970 0:00 UTC)
T1="$(date +%s)"
isdebug echo "Start Time in seconds: ${T1}"
# sometimes there are continuous ticks, skip them.
sleep 1
while [ $new_count -eq $old_count ]
do
new_count=$(get_tick_count)
done
isdebug echo "sampling over: " $new_count
T2="$(date +%s)"
isdebug echo "End Time in seconds: ${T2}"
T=$(($T2-$T1))
isdebug echo "Time in seconds: "
echo $T
isdebug echo ""
if [ $T -lt $MIN_ISOLATION -a $RESULT="PASS" ]; then
RESULT="FAIL"
fi
done
isdebug echo "Result:"
echo $RESULT": "$MIN_ISOLATION
isdebug echo ""
}
isolate_cpu1() {
isdebug echo ""
isdebug echo "Started Isolating CPUs - via CPUSETS"
isdebug echo "------------------------------------"
isdebug echo ""
# Check that we have cpusets enabled in the kernel
if ! grep -q -s cpuset /proc/filesystems ; then
echo "Error: Kernel is lacking support for cpuset!"
exit 1
fi
# Try to disable sched_tick_max_deferment
if [ -d /sys/kernel/debug -a -f /sys/kernel/debug/sched_tick_max_deferment ]; then
echo -1 > /sys/kernel/debug/sched_tick_max_deferment
else
sysctl -e kernel.sched_tick_max_deferment=-1
fi
# Below doesn't work
# sysctl -e kernel.sched_tick_max_deferment=-1
# make sure that the /dev/cpuset dir exits
# and mount the cpuset filesystem if needed
[ -d /dev/cpuset ] || mkdir /dev/cpuset
mount | grep /dev/cpuset > /dev/null || mount -t cpuset none /dev/cpuset
# Create 2 cpusets. One GP and one NOHZ domain.
[ -d /dev/cpuset/gp ] || mkdir /dev/cpuset/gp
[ -d /dev/cpuset/rt ] || mkdir /dev/cpuset/rt
# Setup the GP domain: CPU0
echo 0 > /dev/cpuset/gp/mems
echo 0 > /dev/cpuset/gp/cpus
# Setup the NOHZ domain: CPU1
echo 0 > /dev/cpuset/rt/mems
echo 1 > /dev/cpuset/rt/cpus
# Try to move all processes in top set to the GP set.
for pid in `cat /dev/cpuset/tasks`; do
if [ -d /proc/$pid ]; then
echo $pid > /dev/cpuset/gp/tasks 2>/dev/null
if [ $? != 0 ]; then
isdebug echo -n "Cannot move PID $pid: "
isdebug echo "$(cat /proc/$pid/status | grep ^Name | cut -f2)"
fi
fi
done
# Disable load balancing on top level (otherwise the child-sets' setting
# won't take effect.)
echo 0 > /dev/cpuset/sched_load_balance
# Enable load balancing withing the GP domain
echo 1 > /dev/cpuset/gp/sched_load_balance
# But disallow load balancing within the NOHZ domain
echo 0 > /dev/cpuset/rt/sched_load_balance
# Allow maximum tick deferment
#echo -1 > /sys/kernel/debug/sched_tick_max_deferment
# Start a single threaded task on CPU1 or RT group
echo $$ > /dev/cpuset/rt/tasks
stress -q --cpu 1 --timeout 2000 &
echo $$ > /dev/cpuset/gp/tasks
}
clear_cpusets() {
isdebug echo ""
isdebug echo "Started cleaning CPUSETS"
isdebug echo "------------------------"
isdebug echo ""
#
# Cleanup
#
# kill all instances of stress
for i in `ps | grep stress | sed 's/^\ *//g' | cut -d' ' -f1`;
do
kill -9 $i;
done
# Try to move all from GP back to root
for pid in `cat /dev/cpuset/gp/tasks`; do
if [ -d /proc/$pid ]; then
echo $pid > /dev/cpuset/tasks 2>/dev/null
if [ $? != 0 ]; then
isdebug echo -n "Cannot move PID $pid: "
isdebug echo "$(cat /proc/$pid/status | grep ^Name | cut -f2)"
fi
fi
done
# Remove the CPUsets
rmdir /dev/cpuset/gp
rmdir /dev/cpuset/rt
}
# tests to run
isolate_cpu1
get_isolation_duration
clear_cpusets
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