From: Jiri Olsa <jolsa@redhat.com>
To: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Stephane Eranian <eranian@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH V3 0/5] bugs fix for large PEBS mmap read and rdpmc read
Date: Tue, 30 Jan 2018 19:52:12 +0100 [thread overview]
Message-ID: <20180130185212.GA16806@krava> (raw)
In-Reply-To: <24210bcb-0e4b-58fe-bcda-da30019f6e7e@linux.intel.com>
On Tue, Jan 30, 2018 at 11:48:18AM -0500, Liang, Kan wrote:
SNIP
> > >
> > > The events in fixed mode could enable large PEBS. Events in freq mode should
> > > not enable large PEBS.
> > > I think that could be a problem if some events try to enable large PEBS,
> > > while others not.
> > >
> > You only enable large PEBS if 100% of the events use fixed periods,
> > either via -c period
> > or because they all use individual period=p. The --no-period could
> > also be used to remove
> > the period for measurements where the period is not needed.
>
>
> Oh, right, the kernel has already guaranteed that.
> if (cpuc->n_pebs == cpuc->n_large_pebs) {
> threshold = ds->pebs_absolute_maximum -
> x86_pmu.max_pebs_events * x86_pmu.pebs_record_size;
> } else {
>
> Sorry for the noise.
>
> jirka's patch looks good to me.
cool, I'll post it later this week
thanks,
jirka
next prev parent reply other threads:[~2018-01-30 18:52 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-29 16:29 [PATCH V3 0/5] bugs fix for large PEBS mmap read and rdpmc read kan.liang
2018-01-29 16:29 ` [PATCH V3 1/5] perf/x86/intel: fix event update for auto-reload kan.liang
2018-02-06 15:06 ` Peter Zijlstra
2018-02-06 17:58 ` Liang, Kan
2018-02-09 14:09 ` Peter Zijlstra
2018-02-09 15:49 ` Liang, Kan
2018-02-10 14:09 ` Peter Zijlstra
2018-01-29 16:29 ` [PATCH V3 2/5] perf/x86: introduce read function for x86_pmu kan.liang
2018-01-29 16:29 ` [PATCH V3 3/5] perf/x86/intel/ds: introduce read function for large pebs kan.liang
2018-01-29 16:29 ` [PATCH V3 4/5] perf/x86/intel: fix pmu read for large PEBS kan.liang
2018-01-29 16:29 ` [PATCH V3 5/5] perf/x86: fix: disable userspace RDPMC usage " kan.liang
2018-01-30 9:16 ` [PATCH V3 0/5] bugs fix for large PEBS mmap read and rdpmc read Stephane Eranian
2018-01-30 13:39 ` Jiri Olsa
2018-01-30 14:59 ` Liang, Kan
2018-01-30 15:04 ` Jiri Olsa
2018-01-30 15:25 ` Liang, Kan
2018-01-30 16:36 ` Stephane Eranian
2018-01-30 16:48 ` Liang, Kan
2018-01-30 18:52 ` Jiri Olsa [this message]
2018-01-30 19:56 ` Stephane Eranian
2018-01-31 3:59 ` Andi Kleen
2018-01-31 9:15 ` Jiri Olsa
2018-01-31 13:15 ` Jiri Olsa
2018-01-31 15:15 ` Liang, Kan
2018-01-31 15:41 ` Jiri Olsa
2018-01-30 14:41 ` Liang, Kan
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