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[24.9.64.241]) by smtp.gmail.com with ESMTPSA id y7sm204499oov.26.2020.07.07.08.40.14 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 07 Jul 2020 08:40:15 -0700 (PDT) Subject: Re: [PATCH 2/2] selftest/cpuidle: Add support for cpuidle latency measurement To: Pratik Rajesh Sampat , rjw@rjwysocki.net, daniel.lezcano@linaro.org, mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org, srivatsa@csail.mit.edu, shuah@kernel.org, ego@linux.vnet.ibm.com, svaidy@linux.ibm.com, linux-pm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20200707152917.10652-1-psampat@linux.ibm.com> <20200707152917.10652-3-psampat@linux.ibm.com> Cc: Shuah Khan From: Shuah Khan Message-ID: Date: Tue, 7 Jul 2020 09:40:14 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200707152917.10652-3-psampat@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/7/20 9:29 AM, 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 > --- > tools/testing/selftests/Makefile | 1 + > tools/testing/selftests/cpuidle/Makefile | 6 + > tools/testing/selftests/cpuidle/cpuidle.sh | 240 +++++++++++++++++++++ > tools/testing/selftests/cpuidle/settings | 1 + > 4 files changed, 248 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 > > 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..11666fe47c34 > --- /dev/null > +++ b/tools/testing/selftests/cpuidle/cpuidle.sh > @@ -0,0 +1,240 @@ > +#!/bin/bash > +# SPDX-License-Identifier: GPL-2.0 > + > +LOG=cpuidle.log > +MODULE=/lib/modules/$(uname -r)/kernel/drivers/cpuidle/test-cpuidle_latency.ko > + > +helpme() > +{ > + printf "Usage: $0 [-h] [-todg args] > + [-h ] > + [-m ] > + [-o ] > + \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 2 Please use ksft_skip code to indicate the test is being skipped. > + fi > + printf "Inserting $MODULE module\n\n" > + insmod $MODULE > + if [ $? != 0 ]; then > + printf "Insmod $MODULE failed\n" > + exit 2 This is fine since you expect to be able to load the module. > + fi > +} > + > +compute_average() > +{ > + arr=("$@") > + 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 + do > + for ((state=0; state + do > + echo 1 > /sys/devices/system/cpu/cpu$cpu/cpuidle/state$state/disable > + done > + done > +} > + > +# Enable the idle state supplied > +# $1: State to enable > +enable_state() > +{ > + for ((cpu=0; cpu + do > + echo 0 > /sys/devices/system/cpu/cpu$cpu/cpuidle/state$1/disable > + done > +} > + > +# Extract latency in microseconds and convert to nanoseconds > +extract_latency() > +{ > + for ((state=0; state + do > + latency=$(($(cat /sys/devices/system/cpu/cpu0/cpuidle/state$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 $dest_cpu yes "" > /dev/null & > + yes_pid=$! > + 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 $yes_pid > + wait $yes_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 > + declare -a baseline_avg_array > + > + echo -e "--IPI Latency Test---" >> $LOG > + for ((state=0; state + do > + echo -e "---Enabling state: $state---" >> $LOG > + enable_state $state > + printf "%s %10s %12s %12s\n" "SRC_CPU" "DEST_CPU" "Base_IPI_Latency(ns)" "IPI_Latency(ns)" >> $LOG > + unset avg_arr > + unset baseline_avg_arr > + for ((cpu=0; cpu + do > + # Running IPI test and logging results > + ipi_test_once "baseline" $cpu > + baseline_ipi_latency=$ipi_latency > + ipi_test_once "test" $cpu > + printf "%-3s %10s %12s %18s\n" $src_cpu $cpu $baseline_ipi_latency $ipi_latency >> $LOG > + avg_arr+=($ipi_latency) > + baseline_avg_arr+=($baseline_ipi_latency) > + done > + compute_average "${avg_arr[@]}" > + local avg_latency=$avg > + compute_average "${baseline_avg_arr[@]}" > + local baseline_avg_latency=$avg > + echo -e "Expected IPI latency(ns): ${latency_arr[$state]}" >> $LOG > + echo -e "Baseline Average IPI latency(ns): $baseline_avg_latency" >> $LOG > + echo -e "Observed Average IPI latency(ns): $avg_latency" >> $LOG > + done > +} > + > +# Extract the residency in microseconds and convert to nanoseconds. > +# Add 100 ns so that the timer stays for a little longer than the residency > +extract_residency() > +{ > + for ((state=0; state + do > + residency=$(($(cat /sys/devices/system/cpu/cpu0/cpuidle/state$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 $dest_cpu yes "" > /dev/null & > + yes_pid=$! > + fi > + taskset -c $dest_cpu echo $3 > /sys/kernel/debug/latency_test/timeout_expected_ns > + sleep 0.1 > + timeout_diff=$(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 $yes_pid > + wait $yes_pid 2>/dev/null > + fi > +} > + > +run_timeout_tests() > +{ > + extract_residency > + disable_idle > + declare -a avg_arr > + declare -a baseline_avg_arr > + echo -e "\n--Timeout Latency Test--" >> $LOG > + > + for ((state=0; state + do > + echo -e "---Enabling state: $state---" >> $LOG > + enable_state $state > + printf "%s %10s %10s\n" "Wakeup_src" "Baseline_delay(ns)" "Delay(ns)" >> $LOG > + unset avg_arr > + unset baseline_avg_arr > + for ((cpu=0; cpu + do > + timeout_test_once "baseline" $cpu ${residency_arr[$state]} > + local baseline_timeout_diff=$timeout_diff > + 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) > + baseline_avg_arr+=($baseline_timeout_diff) > + done > + compute_average "${baseline_avg_arr[@]}" > + local baseline_avg=$avg > + compute_average "${avg_arr[@]}" > + echo -e "Expected timeout(ns): ${residency_arr[$state]}" >> $LOG > + echo -e "Baseline Average timeout diff(ns): $baseline_avg" >> $LOG > + echo -e "Observed Average timeout diff(ns): $avg" >> $LOG > + 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 > thanks, -- Shuah