Messages in this thread | | | Subject | Re: [PATCH v4 4/6] perf arm-spe: Assign kernel time to synthesized event | From | James Clark <> | Date | Thu, 15 Apr 2021 17:46:31 +0300 |
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On 12/04/2021 12:10, Leo Yan wrote: > In current code, it assigns the arch timer counter to the synthesized > samples Arm SPE trace, thus the samples don't contain the kernel time > but only contain the raw counter value. > > To fix the issue, this patch converts the timer counter to kernel time > and assigns it to sample timestamp. > > Signed-off-by: Leo Yan <leo.yan@linaro.org> > --- > tools/perf/util/arm-spe.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c > index 23714cf0380e..c13a89f06ab8 100644 > --- a/tools/perf/util/arm-spe.c > +++ b/tools/perf/util/arm-spe.c > @@ -234,7 +234,7 @@ static void arm_spe_prep_sample(struct arm_spe *spe, > struct arm_spe_record *record = &speq->decoder->record; > > if (!spe->timeless_decoding) > - sample->time = speq->timestamp; > + sample->time = tsc_to_perf_time(record->timestamp, &spe->tc);
I noticed that in arm_spe_recording_options() the TIME sample bit is set regardless of any options. I don't know of a way to remove this, and if there isn't, does that mean that all the code in this file that looks at spe->timeless_decoding is untested and has never been hit?
Unless there is a way to get a perf file with only the AUXTRACE event and no others? I think that one might have no timestamp set. Otherwise other events will always have timestamps so spe->timeless_decoding is always false.
> > sample->ip = record->from_ip; > sample->cpumode = arm_spe_cpumode(spe, sample->ip); >
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