Re: [PATCH v2] perf evsel: Improve callchain warning for s390
Jens Remus <[email protected]>
| Newsgroups | org.kernel.vger.linux-perf-users,org.kernel.vger.linux-kernel,org.kernel.vger.linux-s390 |
|---|---|
| Organization | IBM Deutschland Research & Development GmbH |
| Message-ID | <[email protected]> |
On 8/21/2026 2:55 PM, Jens Remus wrote:
> Instead, warn on s390 when callchain sampling is requested with an event
> provided by the CPUMSF hardware PMU, because that combination is not
> supported.
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> @@ -1078,9 +1078,8 @@ static void __evsel__config_callchain(struct evsel *evsel, const struct record_o
> bool function = evsel__is_function_event(evsel);
> struct perf_event_attr *attr = &evsel->core.attr;
>
> - if (EM_HOST == EM_S390 && param->record_mode == CALLCHAIN_FP) {
> - pr_warning_once(
> - "Framepointer unwinding lacks kernel support. Use '--call-graph dwarf'\n");
> + if (EM_HOST == EM_S390 && evsel->pmu && !perf_pmu__is_software(evsel->pmu)) {
> + pr_warning_once("Cannot use hardware CPUMSF event with -g and --call-graph.\n");
Jan, Thomas, could you please do me a favor and test whether this works
as expected on LPAR with CPUMSF? Time was running out before I leave on
vacation.
> }
>
> evsel__set_sample_bit(evsel, CALLCHAIN);
Thanks and regards,
Jens
--
Jens Remus
Linux on Z Development (D3303)
[email protected] / [email protected]
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