From: peterz@infradead.org
To: 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: Fri, 24 Jul 2020 15:19:06 +0200 [thread overview]
Message-ID: <20200724131906.GW119549@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200723171117.9918-9-kan.liang@linux.intel.com>
On Thu, Jul 23, 2020 at 10:11:11AM -0700, kan.liang@linux.intel.com wrote:
> @@ -3375,6 +3428,72 @@ static int intel_pmu_hw_config(struct perf_event *event)
> if (event->attr.type != PERF_TYPE_RAW)
> return 0;
>
> + /*
> + * Config Topdown slots and metric events
> + *
> + * The slots event on Fixed Counter 3 can support sampling,
> + * which will be handled normally in x86_perf_event_update().
> + *
> + * The metric events don't support sampling.
> + *
> + * For counting, topdown slots and metric events will be
> + * handled specially for event update.
> + * A flag PERF_X86_EVENT_TOPDOWN is applied for the case.
> + */
> + if (x86_pmu.intel_cap.perf_metrics && is_topdown_event(event)) {
> + if (is_metric_event(event)) {
> + struct perf_event *leader = event->group_leader;
> + struct perf_event *sibling;
> +
> + /* The metric events don't support sampling. */
> + if (is_sampling_event(event))
> + return -EINVAL;
> +
> + /* The metric events cannot be a group leader. */
> + if (leader == event)
> + return -EINVAL;
> +
> + /*
> + * The slots event cannot be the leader of a topdown
> + * sample-read group, e.g., {slots, topdown-retiring}:S
> + */
> + if (is_slots_event(leader) && is_sampling_event(leader))
> + return -EINVAL;
This has nothing to do with sample-read; SLOTS cannot be sampling when
coupled with the METRIC stuff because hardware is daft.
And you can have SAMPLE_READ on non-leader events just fine.
> +
> + /*
> + * The slots event must be before the metric events,
> + * because we only update the values of a topdown
> + * group once with the slots event.
> + */
> + if (!is_slots_event(leader)) {
> + for_each_sibling_event(sibling, leader) {
> + if (is_slots_event(sibling))
> + break;
> + if (is_metric_event(sibling))
> + return -EINVAL;
> + }
> + }
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;
> + }
> +
> + if (!is_sampling_event(event)) {
> + if (event->attr.config1 != 0)
> + return -EINVAL;
How does this depend on sampling?
> + /*
> + * The TopDown metrics events and slots event don't
> + * support any filters.
> + */
> + if (event->attr.config & X86_ALL_EVENT_FLAGS)
> + return -EINVAL;
That seems independent of sampling too. Even a sampling SLOTS shouldn't
be having any of those afaict.
> +
> + event->hw.flags |= PERF_X86_EVENT_TOPDOWN;
This is confusing too, a !sampling SLOTS event without METRIC siblings
shouldn't have this set, right? So arguably, this should be like above.
> +
> + event->event_caps |= PERF_EV_CAP_COEXIST;
> +
> + if (is_metric_event(event))
> + event->hw.flags &= ~PERF_X86_EVENT_RDPMC_ALLOWED;
This too seems like something that should be in the is_metric_event()
branch above.
> + }
> + }
> +
> if (!(event->attr.config & ARCH_PERFMON_EVENTSEL_ANY))
> return 0;
>
next prev parent reply other threads:[~2020-07-24 13:19 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 [this message]
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
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
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