Re: [PATCH v1] perf test expr: Fix system_tsc_freq for only x86

From: Namhyung Kim
Date: Thu Dec 05 2024 - 00:47:13 EST


Hi Ian,

On Wed, Dec 04, 2024 at 06:23:05PM -0800, Ian Rogers wrote:
> The refactoring of tool PMU events to have a PMU then adding the expr
> literals to the tool PMU made it so that the literal system_tsc_freq
> was only supported on x86. Update the test expectations to match -
> namely the parsing is x86 specific and only yields a non-zero value on
> Intel.
>
> Fixes: 609aa2667f67 ("perf tool_pmu: Switch to standard pmu functions and json descriptions")
> Reported-by: Athira Rajeev <atrajeev@xxxxxxxxxxxxxxxxxx>
> Closes: https://lore.kernel.org/linux-perf-users/20241022140156.98854-1-atrajeev@xxxxxxxxxxxxxxxxxx/
> Co-developed-by: Athira Rajeev <atrajeev@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>

It failed on my VM.

root@arm64-vm:~/build# ./perf test -v 7
--- start ---
test child forked, pid 2096
Using CPUID 0x00000000000f0510
division by zero
syntax error
Unrecognized literal '#system_tsc_freq'FAILED tests/expr.c:253 #system_tsc_freq == 0
---- end(-1) ----
7: Simple expression parser : FAILED!

> ---
> tools/perf/tests/expr.c | 19 ++++++++++++-------
> 1 file changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/tools/perf/tests/expr.c b/tools/perf/tests/expr.c
> index 41ff1affdfcd..726cf8d4da28 100644
> --- a/tools/perf/tests/expr.c
> +++ b/tools/perf/tests/expr.c
> @@ -75,14 +75,12 @@ static int test__expr(struct test_suite *t __maybe_unused, int subtest __maybe_u
> double val, num_cpus_online, num_cpus, num_cores, num_dies, num_packages;
> int ret;
> struct expr_parse_ctx *ctx;
> - bool is_intel = false;
> char strcmp_cpuid_buf[256];
> struct perf_cpu cpu = {-1};
> char *cpuid = get_cpuid_allow_env_override(cpu);
> char *escaped_cpuid1, *escaped_cpuid2;
>
> TEST_ASSERT_VAL("get_cpuid", cpuid);
> - is_intel = strstr(cpuid, "Intel") != NULL;
>
> TEST_ASSERT_EQUAL("ids_union", test_ids_union(), 0);
>
> @@ -245,12 +243,19 @@ static int test__expr(struct test_suite *t __maybe_unused, int subtest __maybe_u
> if (num_dies) // Some platforms do not have CPU die support, for example s390
> TEST_ASSERT_VAL("#num_dies >= #num_packages", num_dies >= num_packages);
>
> - TEST_ASSERT_VAL("#system_tsc_freq", expr__parse(&val, ctx, "#system_tsc_freq") == 0);
> - if (is_intel)
> - TEST_ASSERT_VAL("#system_tsc_freq > 0", val > 0);
> - else
> - TEST_ASSERT_VAL("#system_tsc_freq == 0", fpclassify(val) == FP_ZERO);
>
> + if (expr__parse(&val, ctx, "#system_tsc_freq") == 0) {
> + bool is_intel = strstr(cpuid, "Intel") != NULL;
> +
> + if (is_intel)
> + TEST_ASSERT_VAL("#system_tsc_freq > 0", val > 0);

Also Sasha reported that some (Intel?) guest machine doesn't have TSC
frequency.

Thanks,
Namhyung


> + else
> + TEST_ASSERT_VAL("#system_tsc_freq == 0", fpclassify(val) == FP_ZERO);
> + } else {
> +#if defined(__i386__) || defined(__x86_64__)
> + TEST_ASSERT_VAL("#system_tsc_freq unsupported", 0);
> +#endif
> + }
> /*
> * Source count returns the number of events aggregating in a leader
> * event including the leader. Check parsing yields an id.
> --
> 2.47.0.338.g60cca15819-goog
>