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

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Date:   Wed, 7 Sep 2022 13:44:57 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Namhyung Kim <namhyung@...nel.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...nel.org>
Cc:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Ian Rogers <irogers@...gle.com>,
        linux-perf-users@...r.kernel.org
Subject: Re: [PATCH 2/6] perf test: Use a test program in perf record tests

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@linux.intel.com/

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@...nel.org>
> ---
>  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
>