Re: [PATCH 2/6] perf test: Use a test program in perf record tests

From: Adrian Hunter
Date: Wed Sep 07 2022 - 06:45:13 EST


On 7/09/22 09:46, Namhyung Kim wrote:
> If the system has cc it could build a test program with two threads
> and then use it for more detailed testing. Also it adds initial delay
> of 3ms to profile a multi-threaded target. This change make the test
> failing but that's what we want to check for now.

So the delay is just to get a separate dummy event?

I hit the issue from this patch:

https://lore.kernel.org/lkml/20220711180706.3418612-1-kan.liang@xxxxxxxxxxxxxxx/

That is, if I apply the patch above then the test passes, otherwise it fails always.

>
> If cc is not found, it falls back to use the default value 'true'.
>
> Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> ---
> tools/perf/tests/shell/record.sh | 58 +++++++++++++++++++++++++++++---
> 1 file changed, 54 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh
> index 40b087bfdb76..cea3c7b7e2cd 100755
> --- a/tools/perf/tests/shell/record.sh
> +++ b/tools/perf/tests/shell/record.sh
> @@ -6,10 +6,18 @@ set -e
>
> err=0
> perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
> +testprog=$(mktemp /tmp/__perf_test.prog.XXXXXX)
> +testsym="test_loop"
> +testopt="-D 3"
>
> cleanup() {
> rm -f ${perfdata}
> rm -f ${perfdata}.old
> +
> + if [ "${testprog}" != "true" ]; then
> + rm -f ${testprog}
> + fi
> +
> trap - exit term int
> }
>
> @@ -19,9 +27,49 @@ trap_cleanup() {
> }
> trap trap_cleanup exit term int
>
> +build_test_program() {
> + if ! [ -x "$(command -v cc)" ]; then
> + # No CC found. Fall back to 'true'
> + testprog=true
> + testsym=true
> + testopt=''
> + return
> + fi
> +
> + echo "Build a test program"
> + cat <<EOF | cc -o ${testprog} -xc - -pthread
> +#include <stdio.h>
> +#include <unistd.h>
> +#include <pthread.h>
> +
> +void test_loop(void) {
> + volatile int count = 1000000;
> +
> + // wait for perf record
> + usleep(5000);
> +
> + while (count--)
> + continue;
> +}
> +
> +void *thfunc(void *arg) {
> + test_loop();
> + return NULL;
> +}
> +
> +int main(void) {
> + pthread_t th;
> + pthread_create(&th, NULL, thfunc, NULL);
> + test_loop();
> + pthread_join(th, NULL);
> + return 0;
> +}
> +EOF
> +}
> +
> test_per_thread() {
> echo "Basic --per-thread mode test"
> - if ! perf record -o /dev/null --quiet true 2> /dev/null
> + if ! perf record -o /dev/null --quiet ${testprog} 2> /dev/null
> then
> echo "Per-thread record [Skipped event not supported]"
> if [ $err -ne 1 ]
> @@ -30,13 +78,13 @@ test_per_thread() {
> fi
> return
> fi
> - if ! perf record --per-thread -o ${perfdata} true 2> /dev/null
> + if ! perf record --per-thread ${testopt} -o ${perfdata} ${testprog} 2> /dev/null
> then
> echo "Per-thread record [Failed record]"
> err=1
> return
> fi
> - if ! perf report -i ${perfdata} -q | egrep -q true
> + if ! perf report -i ${perfdata} -q | egrep -q ${testsym}
> then
> echo "Per-thread record [Failed missing output]"
> err=1
> @@ -62,7 +110,7 @@ test_register_capture() {
> return
> fi
> if ! perf record -o - --intr-regs=di,r8,dx,cx -e cpu/br_inst_retired.near_call/p \
> - -c 1000 --per-thread true 2> /dev/null \
> + -c 1000 --per-thread ${testopt} ${testprog} 2> /dev/null \
> | perf script -F ip,sym,iregs -i - 2> /dev/null \
> | egrep -q "DI:"
> then
> @@ -73,6 +121,8 @@ test_register_capture() {
> echo "Register capture test [Success]"
> }
>
> +build_test_program
> +
> test_per_thread
> test_register_capture
>