linux-kernel - Re: [PATCH v2] perf test: Skip Intel TPEBS under hypervisor

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Z5kW69biAERrAFxe@google.com>
Date: Tue, 28 Jan 2025 09:42:03 -0800
From: Namhyung Kim <namhyung@...nel.org>
To: Ian Rogers <irogers@...gle.com>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Kan Liang <kan.liang@...ux.intel.com>,
	James Clark <james.clark@...aro.org>,
	Weilin Wang <weilin.wang@...el.com>,
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] perf test: Skip Intel TPEBS under hypervisor

On Mon, Jan 27, 2025 at 08:37:39PM -0800, Ian Rogers wrote:
> Intel TPEBS test skips on non-Intel CPUs. On Intel CPUs under a
> hypervisor the cache-misses event may not be present. Skip the test
> under this condition.
> 
> Refactor the output code to be placed in a file so that on a signal
> the file can be dumped. This was necessary to catch the issue above as
> the failing perf record command would fail without output.
> 
> Signed-off-by: Ian Rogers <irogers@...gle.com>
> ---
> v2: Fix lost :R and use :p with record as it is ignored by perf stat.
> ---
>  .../perf/tests/shell/test_stat_intel_tpebs.sh | 36 +++++++++++--------
>  1 file changed, 22 insertions(+), 14 deletions(-)
> 
> diff --git a/tools/perf/tests/shell/test_stat_intel_tpebs.sh b/tools/perf/tests/shell/test_stat_intel_tpebs.sh
> index 695dcb93bb5e..a330ecdb7ba5 100755
> --- a/tools/perf/tests/shell/test_stat_intel_tpebs.sh
> +++ b/tools/perf/tests/shell/test_stat_intel_tpebs.sh
> @@ -20,31 +20,39 @@ then
>    exit 2
>  fi
>  
> +stat_output=$(mktemp /tmp/__perf_stat_tpebs_output.XXXXX)
> +
>  cleanup() {
> +  rm -rf "${stat_output}"
>    trap - EXIT TERM INT
>  }
>  
>  trap_cleanup() {
>    echo "Unexpected signal in ${FUNCNAME[1]}"
> +  cat "${stat_output}"
>    cleanup
>    exit 1
>  }
>  trap trap_cleanup EXIT TERM INT
>  
> -# Use this event for testing because it should exist in all platforms
> -event=cache-misses:R
> -
> -# Hybrid platforms output like "cpu_atom/cache-misses/R", rather than as above
> -alt_name=/cache-misses/R
> +# Event to be used in tests
> +event=cache-misses
>  
> -# Without this cmd option, default value or zero is returned
> -#echo "Testing without --record-tpebs"
> -#result=$(perf stat -e "$event" true 2>&1)
> -#[[ "$result" =~ $event || "$result" =~ $alt_name ]] || exit 1
> +if ! perf record -e "${event}:p" -a -o /dev/null sleep 0.01 > "${stat_output}" 2>&1

Shouldn't it simply be

  if ! perf list hw | grep -q cache-misses

?  Doesn't it work on hybrid?

Thanks,
Namhyung


> +then
> +  echo "Missing ${event} support"
> +  cleanup
> +  exit 2
> +fi
>  
>  test_with_record_tpebs() {
>    echo "Testing with --record-tpebs"
> -  result=$(perf stat -e "$event" --record-tpebs -a sleep 0.01 2>&1)
> +  if ! perf stat -e "${event}:R" --record-tpebs -a sleep 0.01 > "${stat_output}" 2>&1
> +  then
> +    echo "Testing with --record-tpebs [Failed perf stat]"
> +    cat "${stat_output}"
> +    exit 1
> +  fi
>  
>    # Expected output:
>    # $ perf stat --record-tpebs -e cache-misses:R -a sleep 0.01
> @@ -57,16 +65,16 @@ test_with_record_tpebs() {
>    #                  0      cache-misses:R
>    #
>    #        0.013963299 seconds time elapsed
> -  if [[ ! "$result" =~ "perf record" ]]
> +  if ! grep "perf record" "${stat_output}"
>    then
>      echo "Testing with --record-tpebs [Failed missing perf record]"
> -    echo "$result"
> +    cat "${stat_output}"
>      exit 1
>    fi
> -  if [[ ! "$result" =~ $event && ! "$result" =~ $alt_name ]]
> +  if ! grep "${event}:R" "${stat_output}" && ! grep "/${event}/R" "${stat_output}"
>    then
>      echo "Testing with --record-tpebs [Failed missing event name]"
> -    echo "$result"
> +    cat "${stat_output}"
>      exit 1
>    fi
>    echo "Testing with --record-tpebs [Success]"
> -- 
> 2.48.1.262.g85cc9f2d1e-goog
>