From: Peter Zijlstra <peterz@infradead.org>
To: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: acme@redhat.com, mingo@kernel.org, linux-kernel@vger.kernel.org,
jolsa@kernel.org, eranian@google.com,
alexander.shishkin@linux.intel.com, ak@linux.intel.com,
like.xu@linux.intel.com
Subject: Re: [PATCH V7 08/14] perf/x86/intel: Generic support for hardware TopDown metrics
Date: Tue, 28 Jul 2020 14:32:40 +0200 [thread overview]
Message-ID: <20200728123240.GJ10769@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <ddeae082-c38d-a961-4d90-1fbc1c9f2726@linux.intel.com>
On Fri, Jul 24, 2020 at 03:10:52PM -0400, Liang, Kan wrote:
> > > > Per the SIBLING patch this then wants to be:
> > > >
> > > > if (!is_slots_event(leader))
> > > > return -EINVAL;
> > > >
> > > > event->event_caps |= PERF_EV_CAP_SIBLING.
> > > > /*
> > > > * Only once we have a METRICs sibling to we
> > > > * need TopDown magic.
> > > > */
> > > > leader->hw.flags |= PERF_X86_EVENT_TOPDOWN;
>
> Since we only set the flag for the SLOTS event now, the V7 patch will treat
> the metric events as normal events, which trigger an error.
Damn, that was a silly oversight on my part.
> I think we don't need the PERF_X86_EVENT_TOPDOWN flag anymore.
> If it's a non-sampling slots event, apply the special function.
> If it's a metric event, do nothing.
> diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
> index 0f3d01562ded..02dfee0b6615 100644
> --- a/arch/x86/events/core.c
> +++ b/arch/x86/events/core.c
> @@ -73,10 +73,10 @@ u64 x86_perf_event_update(struct perf_event *event)
> u64 prev_raw_count, new_raw_count;
> u64 delta;
>
> - if (unlikely(!hwc->event_base))
> + if (unlikely(!hwc->event_base || is_metric_event(event)))
> return 0;
>
> - if (unlikely(is_topdown_count(event)) && x86_pmu.update_topdown_event)
> + if (unlikely(is_slots_count(event)) && x86_pmu.update_topdown_event)
> return x86_pmu.update_topdown_event(event);
>
> /*
> @@ -1280,11 +1280,10 @@ int x86_perf_event_set_period(struct perf_event
> *event)
> s64 period = hwc->sample_period;
> int ret = 0, idx = hwc->idx;
>
> - if (unlikely(!hwc->event_base))
> + if (unlikely(!hwc->event_base || is_metric_event(event)))
> return 0;
>
> - if (unlikely(is_topdown_count(event)) &&
> - x86_pmu.set_topdown_event_period)
> + if (unlikely(is_slots_count(event)) && x86_pmu.set_topdown_event_period)
> return x86_pmu.set_topdown_event_period(event);
>
> /*
This; I don't like that much, it adds even more conditions to fairly hot
code.
I was even considering adding a static_branch for
x86_pmu.intel_cap.perf_metrics.
Anyway, let me fix this.
next prev parent reply other threads:[~2020-07-28 12:32 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-23 17:11 [PATCH V7 00/14] TopDown metrics support for Icelake kan.liang
2020-07-23 17:11 ` [PATCH V7 01/14] perf/x86: Use event_base_rdpmc for the RDPMC userspace support kan.liang
2020-08-19 8:52 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-23 17:11 ` [PATCH V7 02/14] perf/x86/intel: Name the global status bit in NMI handler kan.liang
2020-08-19 8:52 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-23 17:11 ` [PATCH V7 03/14] perf/x86/intel: Introduce the fourth fixed counter kan.liang
2020-08-19 8:52 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-23 17:11 ` [PATCH V7 04/14] perf/x86/intel: Move BTS index to 47 kan.liang
2020-08-19 8:52 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-23 17:11 ` [PATCH V7 05/14] perf/x86/intel: Fix the name of perf METRICS kan.liang
2020-08-19 8:52 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-23 17:11 ` [PATCH V7 06/14] perf/x86/intel: Use switch in intel_pmu_disable/enable_event kan.liang
2020-08-19 8:52 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-23 17:11 ` [PATCH V7 07/14] perf/core: Add a new PERF_EV_CAP_COEXIST event capability kan.liang
2020-07-24 10:55 ` peterz
2020-07-24 11:46 ` peterz
2020-07-24 13:43 ` Liang, Kan
2020-07-24 13:54 ` Peter Zijlstra
2020-07-24 14:19 ` Liang, Kan
2020-07-24 14:32 ` Peter Zijlstra
2020-07-24 14:46 ` Andi Kleen
2020-07-24 14:59 ` Peter Zijlstra
2020-07-24 16:43 ` peterz
2020-07-24 17:00 ` Liang, Kan
2020-07-24 14:39 ` Andi Kleen
2020-07-24 14:51 ` Peter Zijlstra
2020-08-19 8:52 ` [tip: perf/core] perf/core: Add a new PERF_EV_CAP_SIBLING " tip-bot2 for Kan Liang
2020-07-23 17:11 ` [PATCH V7 08/14] perf/x86/intel: Generic support for hardware TopDown metrics kan.liang
2020-07-24 13:19 ` peterz
2020-07-24 15:27 ` peterz
2020-07-24 16:07 ` Liang, Kan
2020-07-24 19:10 ` Liang, Kan
2020-07-28 12:32 ` Peter Zijlstra [this message]
2020-07-28 13:09 ` Peter Zijlstra
2020-07-28 13:28 ` Liang, Kan
2020-07-28 13:44 ` peterz
2020-07-28 14:01 ` Liang, Kan
2020-08-19 8:52 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-23 17:11 ` [PATCH V7 09/14] perf/x86: Add a macro for RDPMC offset of fixed counters kan.liang
2020-08-19 8:52 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-23 17:11 ` [PATCH V7 10/14] perf/x86/intel: Support TopDown metrics on Ice Lake kan.liang
2020-08-19 8:52 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-23 17:11 ` [PATCH V7 11/14] perf/x86/intel: Support per-thread RDPMC TopDown metrics kan.liang
2020-08-19 8:52 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-23 17:11 ` [PATCH V7 12/14] perf, tools, stat: Support new per thread " kan.liang
2020-07-24 3:29 ` Andi Kleen
2020-07-23 17:11 ` [PATCH V7 13/14] perf, tools, stat: Check Topdown Metric group kan.liang
2020-07-23 17:11 ` [PATCH V7 14/14] perf, tools: Add documentation for topdown metrics kan.liang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200728123240.GJ10769@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=acme@redhat.com \
--cc=ak@linux.intel.com \
--cc=alexander.shishkin@linux.intel.com \
--cc=eranian@google.com \
--cc=jolsa@kernel.org \
--cc=kan.liang@linux.intel.com \
--cc=like.xu@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).