| Message ID | 20200717091801.29289-3-psampat@linux.ibm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Selftest for cpuidle latency measurement | expand |
Hi Pratik, On Fri, Jul 17, 2020 at 02:48:01PM +0530, Pratik Rajesh Sampat wrote: > This patch adds support to trace IPI based and timer based wakeup > latency from idle states > > Latches onto the test-cpuidle_latency kernel module using the debugfs > interface to send IPIs or schedule a timer based event, which in-turn > populates the debugfs with the latency measurements. > > Currently for the IPI and timer tests; first disable all idle states > and then test for latency measurements incrementally enabling each state > > Signed-off-by: Pratik Rajesh Sampat <psampat@linux.ibm.com> A few comments below. > --- > tools/testing/selftests/Makefile | 1 + > tools/testing/selftests/cpuidle/Makefile | 6 + > tools/testing/selftests/cpuidle/cpuidle.sh | 257 +++++++++++++++++++++ > tools/testing/selftests/cpuidle/settings | 1 + > 4 files changed, 265 insertions(+) > create mode 100644 tools/testing/selftests/cpuidle/Makefile > create mode 100755 tools/testing/selftests/cpuidle/cpuidle.sh > create mode 100644 tools/testing/selftests/cpuidle/settings > [..skip..] > + > +ins_mod() > +{ > + if [ ! -f "$MODULE" ]; then > + printf "$MODULE module does not exist. Exitting\n" If the module has been compiled into the kernel (due to a localyesconfig, for instance), then it is unlikely that we will find it in /lib/modules. Perhaps you want to check if the debugfs directories created by the module exist, and if so, print a message saying that the modules is already loaded or some such? > + exit $ksft_skip > + fi > + printf "Inserting $MODULE module\n\n" > + insmod $MODULE > + if [ $? != 0 ]; then > + printf "Insmod $MODULE failed\n" > + exit $ksft_skip > + fi > +} > + > +compute_average() > +{ > + arr=("$@") > + sum=0 > + size=${#arr[@]} > + for i in "${arr[@]}" > + do > + sum=$((sum + i)) > + done > + avg=$((sum/size)) It would be good to assert that "size" isn't 0 here. > +} > + > +# Disable all stop states > +disable_idle() > +{ > + for ((cpu=0; cpu<NUM_CPUS; cpu++)) > + do > + for ((state=0; state<NUM_STATES; state++)) > + do > + echo 1 > /sys/devices/system/cpu/cpu$cpu/cpuidle/state$state/disable So, on offlined CPUs, we won't see /sys/devices/system/cpu/cpu$cpu/cpuidle/state$state directory. You should probably perform this operation only on online CPUs. > + done > + done > +} > + > +# Perform operation on each CPU for the given state > +# $1 - Operation: enable (0) / disable (1) > +# $2 - State to enable > +op_state() > +{ > + for ((cpu=0; cpu<NUM_CPUS; cpu++)) > + do > + echo $1 > /sys/devices/system/cpu/cpu$cpu/cpuidle/state$2/disable Ditto > + done > +} This is a helper function. For better readability of the main code you can define the following wrappers and use them. cpuidle_enable_state() { state=$1 op_state 1 $state } cpuidle_disable_state() { state=$1 op_state 0 $state } > + [..snip..] > +run_ipi_tests() > +{ > + extract_latency > + disable_idle > + declare -a avg_arr > + echo -e "--IPI Latency Test---" >> $LOG > + > + echo -e "--Baseline IPI Latency measurement: CPU Busy--" >> $LOG > + printf "%s %10s %12s\n" "SRC_CPU" "DEST_CPU" "IPI_Latency(ns)" >> $LOG > + for ((cpu=0; cpu<NUM_CPUS; cpu++)) > + do > + ipi_test_once "baseline" $cpu > + printf "%-3s %10s %12s\n" $src_cpu $cpu $ipi_latency >> $LOG > + avg_arr+=($ipi_latency) > + done > + compute_average "${avg_arr[@]}" > + echo -e "Baseline Average IPI latency(ns): $avg" >> $LOG > + > + for ((state=0; state<NUM_STATES; state++)) > + do > + unset avg_arr > + echo -e "---Enabling state: $state---" >> $LOG > + op_state 0 $state > + printf "%s %10s %12s\n" "SRC_CPU" "DEST_CPU" "IPI_Latency(ns)" >> $LOG > + for ((cpu=0; cpu<NUM_CPUS; cpu++)) > + do If a CPU is offline, then we should skip it here. > + # Running IPI test and logging results > + sleep 1 > + ipi_test_once "test" $cpu > + printf "%-3s %10s %12s\n" $src_cpu $cpu $ipi_latency >> $LOG > + avg_arr+=($ipi_latency) > + done > + compute_average "${avg_arr[@]}" > + echo -e "Expected IPI latency(ns): ${latency_arr[$state]}" >> $LOG > + echo -e "Observed Average IPI latency(ns): $avg" >> $LOG > + op_state 1 $state > + done > +} > + > +# Extract the residency in microseconds and convert to nanoseconds. > +# Add 100 ns so that the timer stays for a little longer than the residency > +extract_residency() > +{ > + for ((state=0; state<NUM_STATES; state++)) > + do > + residency=$(($(cat /sys/devices/system/cpu/cpu0/cpuidle/state$state/residency) * 1000 + 200)) > + residency_arr+=($residency) > + done > +} > + > +# Run the Timeout test > +# $1 run for baseline - busy cpu or regular environment > +# $2 destination cpu > +# $3 timeout > +timeout_test_once() > +{ > + dest_cpu=$2 > + if [ "$1" = "baseline" ]; then > + # Keep the CPU busy > + taskset -c $dest_cpu cat /dev/random > /dev/null & > + task_pid=$! > + # Wait for the workload to achieve 100% CPU usage > + sleep 1 > + fi > + taskset -c $dest_cpu echo $3 > /sys/kernel/debug/latency_test/timeout_expected_ns > + # Wait for the result to populate > + sleep 0.1 > + timeout_diff=$(cat /sys/kernel/debug/latency_test/timeout_diff_ns) > + src_cpu=$(cat /sys/kernel/debug/latency_test/timeout_cpu_src) > + if [ "$1" = "baseline" ]; then > + kill $task_pid > + wait $task_pid 2>/dev/null > + fi > +} > + > +run_timeout_tests() > +{ > + extract_residency > + disable_idle > + declare -a avg_arr > + echo -e "\n--Timeout Latency Test--" >> $LOG > + > + echo -e "--Baseline Timeout Latency measurement: CPU Busy--" >> $LOG > + printf "%s %10s %10s\n" "Wakeup_src" "Baseline_delay(ns)">> $LOG > + for ((cpu=0; cpu<NUM_CPUS; cpu++)) > + do Again only perform this on online CPUs. > + timeout_test_once "baseline" $cpu ${residency_arr[0]} > + printf "%-3s %13s\n" $src_cpu $timeout_diff >> $LOG > + avg_arr+=($timeout_diff) > + done > + compute_average "${avg_arr[@]}" > + echo -e "Baseline Average timeout diff(ns): $avg" >> $LOG > + > + for ((state=0; state<NUM_STATES; state++)) > + do > + echo -e "---Enabling state: $state---" >> $LOG > + op_state 0 $state > + printf "%s %10s %10s\n" "Wakeup_src" "Baseline_delay(ns)" "Delay(ns)" >> $LOG > + unset avg_arr > + for ((cpu=0; cpu<NUM_CPUS; cpu++)) > + do Ditto. > + timeout_test_once "test" $cpu ${residency_arr[$state]} > + printf "%-3s %13s %18s\n" $src_cpu $baseline_timeout_diff $timeout_diff >> $LOG > + avg_arr+=($timeout_diff) > + done > + compute_average "${avg_arr[@]}" > + echo -e "Expected timeout(ns): ${residency_arr[$state]}" >> $LOG > + echo -e "Observed Average timeout diff(ns): $avg" >> $LOG > + op_state 1 $state > + done > +} > + -- Thanks and Regards gautham.
Hi Gautham, Thanks for the review. On 20/07/20 11:22 am, Gautham R Shenoy wrote: > Hi Pratik, > > > On Fri, Jul 17, 2020 at 02:48:01PM +0530, Pratik Rajesh Sampat wrote: >> This patch adds support to trace IPI based and timer based wakeup >> latency from idle states >> >> Latches onto the test-cpuidle_latency kernel module using the debugfs >> interface to send IPIs or schedule a timer based event, which in-turn >> populates the debugfs with the latency measurements. >> >> Currently for the IPI and timer tests; first disable all idle states >> and then test for latency measurements incrementally enabling each state >> >> Signed-off-by: Pratik Rajesh Sampat <psampat@linux.ibm.com> > A few comments below. > >> --- >> tools/testing/selftests/Makefile | 1 + >> tools/testing/selftests/cpuidle/Makefile | 6 + >> tools/testing/selftests/cpuidle/cpuidle.sh | 257 +++++++++++++++++++++ >> tools/testing/selftests/cpuidle/settings | 1 + >> 4 files changed, 265 insertions(+) >> create mode 100644 tools/testing/selftests/cpuidle/Makefile >> create mode 100755 tools/testing/selftests/cpuidle/cpuidle.sh >> create mode 100644 tools/testing/selftests/cpuidle/settings >> > [..skip..] > >> + >> +ins_mod() >> +{ >> + if [ ! -f "$MODULE" ]; then >> + printf "$MODULE module does not exist. Exitting\n" > If the module has been compiled into the kernel (due to a > localyesconfig, for instance), then it is unlikely that we will find > it in /lib/modules. Perhaps you want to check if the debugfs > directories created by the module exist, and if so, print a message > saying that the modules is already loaded or some such? > That's a good idea. I can can grep for this module within /proc/modules and not insert it, if it is already there >> + exit $ksft_skip >> + fi >> + printf "Inserting $MODULE module\n\n" >> + insmod $MODULE >> + if [ $? != 0 ]; then >> + printf "Insmod $MODULE failed\n" >> + exit $ksft_skip >> + fi >> +} >> + >> +compute_average() >> +{ >> + arr=("$@") >> + sum=0 >> + size=${#arr[@]} >> + for i in "${arr[@]}" >> + do >> + sum=$((sum + i)) >> + done >> + avg=$((sum/size)) > It would be good to assert that "size" isn't 0 here. Sure >> +} >> + >> +# Disable all stop states >> +disable_idle() >> +{ >> + for ((cpu=0; cpu<NUM_CPUS; cpu++)) >> + do >> + for ((state=0; state<NUM_STATES; state++)) >> + do >> + echo 1 > /sys/devices/system/cpu/cpu$cpu/cpuidle/state$state/disable > So, on offlined CPUs, we won't see > /sys/devices/system/cpu/cpu$cpu/cpuidle/state$state directory. You > should probably perform this operation only on online CPUs. Right. I should make CPU operations only on online CPUs all over the script [..snip..] Thanks Pratik
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index 1195bd85af38..ab6cf51f3518 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -7,6 +7,7 @@ TARGETS += capabilities TARGETS += cgroup TARGETS += clone3 TARGETS += cpufreq +TARGETS += cpuidle TARGETS += cpu-hotplug TARGETS += drivers/dma-buf TARGETS += efivarfs diff --git a/tools/testing/selftests/cpuidle/Makefile b/tools/testing/selftests/cpuidle/Makefile new file mode 100644 index 000000000000..72fd5d2e974d --- /dev/null +++ b/tools/testing/selftests/cpuidle/Makefile @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0 +all: + +TEST_PROGS := cpuidle.sh + +include ../lib.mk diff --git a/tools/testing/selftests/cpuidle/cpuidle.sh b/tools/testing/selftests/cpuidle/cpuidle.sh new file mode 100755 index 000000000000..5c313a3abb0c --- /dev/null +++ b/tools/testing/selftests/cpuidle/cpuidle.sh @@ -0,0 +1,257 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +LOG=cpuidle.log +MODULE=/lib/modules/$(uname -r)/kernel/drivers/cpuidle/test-cpuidle_latency.ko + +# Kselftest framework requirement - SKIP code is 4. +ksft_skip=4 + +helpme() +{ + printf "Usage: $0 [-h] [-todg args] + [-h <help>] + [-m <location of the module>] + [-o <location of the output>] + \n" + exit 2 +} + +parse_arguments() +{ + while getopts ht:m:o: arg + do + case $arg in + h) # --help + helpme + ;; + m) # --mod-file + MODULE=$OPTARG + ;; + o) # output log files + LOG=$OPTARG + ;; + \?) + helpme + ;; + esac + done +} + +ins_mod() +{ + if [ ! -f "$MODULE" ]; then + printf "$MODULE module does not exist. Exitting\n" + exit $ksft_skip + fi + printf "Inserting $MODULE module\n\n" + insmod $MODULE + if [ $? != 0 ]; then + printf "Insmod $MODULE failed\n" + exit $ksft_skip + fi +} + +compute_average() +{ + arr=("$@") + sum=0 + size=${#arr[@]} + for i in "${arr[@]}" + do + sum=$((sum + i)) + done + avg=$((sum/size)) +} + +# Disable all stop states +disable_idle() +{ + for ((cpu=0; cpu<NUM_CPUS; cpu++)) + do + for ((state=0; state<NUM_STATES; state++)) + do + echo 1 > /sys/devices/system/cpu/cpu$cpu/cpuidle/state$state/disable + done + done +} + +# Perform operation on each CPU for the given state +# $1 - Operation: enable (0) / disable (1) +# $2 - State to enable +op_state() +{ + for ((cpu=0; cpu<NUM_CPUS; cpu++)) + do + echo $1 > /sys/devices/system/cpu/cpu$cpu/cpuidle/state$2/disable + done +} + +# Extract latency in microseconds and convert to nanoseconds +extract_latency() +{ + for ((state=0; state<NUM_STATES; state++)) + do + latency=$(($(cat /sys/devices/system/cpu/cpu0/cpuidle/state$state/latency) * 1000)) + latency_arr+=($latency) + done +} + +# Run the IPI test +# $1 run for baseline - busy cpu or regular environment +# $2 destination cpu +ipi_test_once() +{ + dest_cpu=$2 + if [ "$1" = "baseline" ]; then + # Keep the CPU busy + taskset -c $dest_cpu cat /dev/random > /dev/null & + task_pid=$! + # Wait for the workload to achieve 100% CPU usage + sleep 1 + fi + taskset 0x1 echo $dest_cpu > /sys/kernel/debug/latency_test/ipi_cpu_dest + ipi_latency=$(cat /sys/kernel/debug/latency_test/ipi_latency_ns) + src_cpu=$(cat /sys/kernel/debug/latency_test/ipi_cpu_src) + if [ "$1" = "baseline" ]; then + kill $task_pid + wait $task_pid 2>/dev/null + fi +} + +# Incrementally Enable idle states one by one and compute the latency +run_ipi_tests() +{ + extract_latency + disable_idle + declare -a avg_arr + echo -e "--IPI Latency Test---" >> $LOG + + echo -e "--Baseline IPI Latency measurement: CPU Busy--" >> $LOG + printf "%s %10s %12s\n" "SRC_CPU" "DEST_CPU" "IPI_Latency(ns)" >> $LOG + for ((cpu=0; cpu<NUM_CPUS; cpu++)) + do + ipi_test_once "baseline" $cpu + printf "%-3s %10s %12s\n" $src_cpu $cpu $ipi_latency >> $LOG + avg_arr+=($ipi_latency) + done + compute_average "${avg_arr[@]}" + echo -e "Baseline Average IPI latency(ns): $avg" >> $LOG + + for ((state=0; state<NUM_STATES; state++)) + do + unset avg_arr + echo -e "---Enabling state: $state---" >> $LOG + op_state 0 $state + printf "%s %10s %12s\n" "SRC_CPU" "DEST_CPU" "IPI_Latency(ns)" >> $LOG + for ((cpu=0; cpu<NUM_CPUS; cpu++)) + do + # Running IPI test and logging results + sleep 1 + ipi_test_once "test" $cpu + printf "%-3s %10s %12s\n" $src_cpu $cpu $ipi_latency >> $LOG + avg_arr+=($ipi_latency) + done + compute_average "${avg_arr[@]}" + echo -e "Expected IPI latency(ns): ${latency_arr[$state]}" >> $LOG + echo -e "Observed Average IPI latency(ns): $avg" >> $LOG + op_state 1 $state + done +} + +# Extract the residency in microseconds and convert to nanoseconds. +# Add 100 ns so that the timer stays for a little longer than the residency +extract_residency() +{ + for ((state=0; state<NUM_STATES; state++)) + do + residency=$(($(cat /sys/devices/system/cpu/cpu0/cpuidle/state$state/residency) * 1000 + 200)) + residency_arr+=($residency) + done +} + +# Run the Timeout test +# $1 run for baseline - busy cpu or regular environment +# $2 destination cpu +# $3 timeout +timeout_test_once() +{ + dest_cpu=$2 + if [ "$1" = "baseline" ]; then + # Keep the CPU busy + taskset -c $dest_cpu cat /dev/random > /dev/null & + task_pid=$! + # Wait for the workload to achieve 100% CPU usage + sleep 1 + fi + taskset -c $dest_cpu echo $3 > /sys/kernel/debug/latency_test/timeout_expected_ns + # Wait for the result to populate + sleep 0.1 + timeout_diff=$(cat /sys/kernel/debug/latency_test/timeout_diff_ns) + src_cpu=$(cat /sys/kernel/debug/latency_test/timeout_cpu_src) + if [ "$1" = "baseline" ]; then + kill $task_pid + wait $task_pid 2>/dev/null + fi +} + +run_timeout_tests() +{ + extract_residency + disable_idle + declare -a avg_arr + echo -e "\n--Timeout Latency Test--" >> $LOG + + echo -e "--Baseline Timeout Latency measurement: CPU Busy--" >> $LOG + printf "%s %10s %10s\n" "Wakeup_src" "Baseline_delay(ns)">> $LOG + for ((cpu=0; cpu<NUM_CPUS; cpu++)) + do + timeout_test_once "baseline" $cpu ${residency_arr[0]} + printf "%-3s %13s\n" $src_cpu $timeout_diff >> $LOG + avg_arr+=($timeout_diff) + done + compute_average "${avg_arr[@]}" + echo -e "Baseline Average timeout diff(ns): $avg" >> $LOG + + for ((state=0; state<NUM_STATES; state++)) + do + echo -e "---Enabling state: $state---" >> $LOG + op_state 0 $state + printf "%s %10s %10s\n" "Wakeup_src" "Baseline_delay(ns)" "Delay(ns)" >> $LOG + unset avg_arr + for ((cpu=0; cpu<NUM_CPUS; cpu++)) + do + timeout_test_once "test" $cpu ${residency_arr[$state]} + printf "%-3s %13s %18s\n" $src_cpu $baseline_timeout_diff $timeout_diff >> $LOG + avg_arr+=($timeout_diff) + done + compute_average "${avg_arr[@]}" + echo -e "Expected timeout(ns): ${residency_arr[$state]}" >> $LOG + echo -e "Observed Average timeout diff(ns): $avg" >> $LOG + op_state 1 $state + done +} + +declare -a residency_arr +declare -a latency_arr + +# Parse arguments +parse_arguments $@ + +rm -f $LOG +touch $LOG +NUM_CPUS=$(nproc --all) +NUM_STATES=$(ls -1 /sys/devices/system/cpu/cpu0/cpuidle/ | wc -l) + +# Insert the module +ins_mod $MODULE + +printf "Started IPI latency tests\n" +run_ipi_tests + +printf "Started Timer latency tests\n" +run_timeout_tests + +printf "Removing $MODULE module\n" +printf "Output logged at: $LOG\n" +rmmod $MODULE diff --git a/tools/testing/selftests/cpuidle/settings b/tools/testing/selftests/cpuidle/settings new file mode 100644 index 000000000000..e7b9417537fb --- /dev/null +++ b/tools/testing/selftests/cpuidle/settings @@ -0,0 +1 @@ +timeout=0
This patch adds support to trace IPI based and timer based wakeup latency from idle states Latches onto the test-cpuidle_latency kernel module using the debugfs interface to send IPIs or schedule a timer based event, which in-turn populates the debugfs with the latency measurements. Currently for the IPI and timer tests; first disable all idle states and then test for latency measurements incrementally enabling each state Signed-off-by: Pratik Rajesh Sampat <psampat@linux.ibm.com> --- tools/testing/selftests/Makefile | 1 + tools/testing/selftests/cpuidle/Makefile | 6 + tools/testing/selftests/cpuidle/cpuidle.sh | 257 +++++++++++++++++++++ tools/testing/selftests/cpuidle/settings | 1 + 4 files changed, 265 insertions(+) create mode 100644 tools/testing/selftests/cpuidle/Makefile create mode 100755 tools/testing/selftests/cpuidle/cpuidle.sh create mode 100644 tools/testing/selftests/cpuidle/settings