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SubjectRe: [PATCH] perf test arm-spe: Check if perf-record hangs when recording workload with forks
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On 28/02/2022 16:56, German Gomez wrote:
> Add shell test to check if perf-record hangs when recording an arm_spe
> event with forks.
>
> The test FAILS if the Kernel is not patched with Commit 961c391217 ("perf:
> Always wake the parent event").
>
> Unpatched Kernel:
>
> $ perf test -v 90
> 90: Check Arm SPE doesn't hang when there are forks
> --- start ---
> test child forked, pid 14232
> Recording workload with fork
> Log lines = 90 /tmp/__perf_test.stderr.0Nu0U
> Log lines after 1 second = 90 /tmp/__perf_test.stderr.0Nu0U
> SPE hang test: FAIL
> test child finished with -1
> ---- end ----
> Check Arm SPE trace data in workload with forks: FAILED!
>
> Patched Kernel:
>
> $ perf test -v 90
> 90: Check Arm SPE doesn't hang when there are forks
> --- start ---
> test child forked, pid 2930
> Compiling test program...
> Recording workload...
> Log lines = 478 /tmp/__perf_test.log.026AI
> Log lines after 1 second = 557 /tmp/__perf_test.log.026AI
> SPE hang test: PASS
> Cleaning up files...
> test child finished with 0
> ---- end ----
> Check Arm SPE trace data in workload with forks: Ok
>
> Signed-off-by: German Gomez <german.gomez@arm.com>

Reviewed-by: James Clark <james.clark@arm.com>

> ---
> tools/perf/tests/shell/test_arm_spe_fork.sh | 92 +++++++++++++++++++++
> 1 file changed, 92 insertions(+)
> create mode 100755 tools/perf/tests/shell/test_arm_spe_fork.sh
>
> diff --git a/tools/perf/tests/shell/test_arm_spe_fork.sh b/tools/perf/tests/shell/test_arm_spe_fork.sh
> new file mode 100755
> index 000000000..c920d3583
> --- /dev/null
> +++ b/tools/perf/tests/shell/test_arm_spe_fork.sh
> @@ -0,0 +1,92 @@
> +#!/bin/sh
> +# Check Arm SPE doesn't hang when there are forks
> +
> +# SPDX-License-Identifier: GPL-2.0
> +# German Gomez <german.gomez@arm.com>, 2022
> +
> +skip_if_no_arm_spe_event() {
> + perf list | egrep -q 'arm_spe_[0-9]+//' && return 0
> + return 2
> +}
> +
> +skip_if_no_arm_spe_event || exit 2
> +
> +# skip if there's no compiler
> +if ! [ -x "$(command -v cc)" ]; then
> + echo "failed: no compiler, install gcc"
> + exit 2
> +fi
> +
> +TEST_PROGRAM_SOURCE=$(mktemp /tmp/__perf_test.program.XXXXX.c)
> +TEST_PROGRAM=$(mktemp /tmp/__perf_test.program.XXXXX)
> +PERF_DATA=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
> +PERF_RECORD_LOG=$(mktemp /tmp/__perf_test.log.XXXXX)
> +
> +cleanup_files()
> +{
> + echo "Cleaning up files..."
> + rm -f ${PERF_RECORD_LOG}
> + rm -f ${PERF_DATA}
> + rm -f ${TEST_PROGRAM_SOURCE}
> + rm -f ${TEST_PROGRAM}
> +}
> +
> +trap cleanup_files exit term int
> +
> +# compile test program
> +cat << EOF > $TEST_PROGRAM_SOURCE
> +#include <math.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <unistd.h>
> +#include <sys/wait.h>
> +
> +int workload() {
> + while (1)
> + sqrt(rand());
> + return 0;
> +}
> +
> +int main() {
> + switch (fork()) {
> + case 0:
> + return workload();
> + case -1:
> + return 1;
> + default:
> + wait(NULL);
> + }
> + return 0;
> +}
> +EOF
> +
> +echo "Compiling test program..."
> +CFLAGS="-lm"
> +cc $TEST_PROGRAM_SOURCE $CFLAGS -o $TEST_PROGRAM || exit 1
> +
> +echo "Recording workload..."
> +perf record -o ${PERF_DATA} -e arm_spe/period=65536/ -vvv -- $TEST_PROGRAM > ${PERF_RECORD_LOG} 2>&1 &
> +PERFPID=$!
> +
> +# Check if perf hangs by checking the perf-record logs.
> +sleep 1
> +log0=$(wc -l $PERF_RECORD_LOG)
> +echo Log lines = $log0
> +sleep 1
> +log1=$(wc -l $PERF_RECORD_LOG)
> +echo Log lines after 1 second = $log1
> +
> +kill $PERFPID
> +wait $PERFPID
> +# test program may leave an orphan process running the workload
> +killall $(basename $TEST_PROGRAM)
> +
> +if [ "$log0" = "$log1" ];
> +then
> + echo "SPE hang test: FAIL"
> + exit 1
> +else
> + echo "SPE hang test: PASS"
> +fi
> +
> +exit 0

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