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From: Peter Zijlstra <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
Subject: Re: [PATCH V6 07/14] perf/x86/intel: Generic support for hardware TopDown metrics
Date: Mon, 20 Jul 2020 19:41:03 +0200	[thread overview]
Message-ID: <20200720174103.GV10769@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200717140554.22863-8-kan.liang@linux.intel.com>

On Fri, Jul 17, 2020 at 07:05:47AM -0700, kan.liang@linux.intel.com wrote:

> For the event mapping, a special 0x00 event code is used, which is
> reserved for fake events. The metric events start from umask 0x10.

> +#define INTEL_PMC_IDX_METRIC_BASE		(INTEL_PMC_IDX_FIXED + 16)
> +#define INTEL_PMC_IDX_TD_RETIRING		(INTEL_PMC_IDX_METRIC_BASE + 0)
> +#define INTEL_PMC_IDX_TD_BAD_SPEC		(INTEL_PMC_IDX_METRIC_BASE + 1)
> +#define INTEL_PMC_IDX_TD_FE_BOUND		(INTEL_PMC_IDX_METRIC_BASE + 2)
> +#define INTEL_PMC_IDX_TD_BE_BOUND		(INTEL_PMC_IDX_METRIC_BASE + 3)

So this is internal and we can change it around if/when needed, right?

> +#define INTEL_PMC_IDX_METRIC_END		INTEL_PMC_IDX_TD_BE_BOUND
> +#define INTEL_PMC_MSK_TOPDOWN			((0xfull << INTEL_PMC_IDX_METRIC_BASE) | \
> +						INTEL_PMC_MSK_FIXED_SLOTS)
> +
> +/*
> + * There is no event-code assigned to the TopDown events.
> + *
> + * For the slots event, use the pseudo code of the fixed counter 3.
> + *
> + * For the metric events, the pseudo event-code is 0x00.
> + * The pseudo umask-code starts from 0x10.
> + */
> +#define INTEL_TD_SLOTS				0x0400	/* TOPDOWN.SLOTS */
> +/* Level 1 metrics */
> +#define INTEL_TD_METRIC_RETIRING		0x1000	/* Retiring metric */
> +#define INTEL_TD_METRIC_BAD_SPEC		0x1100	/* Bad speculation metric */
> +#define INTEL_TD_METRIC_FE_BOUND		0x1200	/* FE bound metric */
> +#define INTEL_TD_METRIC_BE_BOUND		0x1300	/* BE bound metric */
> +#define INTEL_TD_METRIC_MAX			INTEL_TD_METRIC_BE_BOUND
> +#define INTEL_TD_METRIC_NUM			4

But this is ABI, once we merge this, it's stuck.

Also, per how Fixed2 is 0x0300, should not Fixed16 (aka
METRICS_RETIRING) be 0x1100 ?

But aside of that, are we sure the hardware will never grow a Fixed16?
Or do we want to be paranoid and move the metrics events up in the
pseudo event space?

  reply	other threads:[~2020-07-20 17:41 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-17 14:05 [PATCH V6 00/14] TopDown metrics support for Icelake kan.liang
2020-07-17 14:05 ` [PATCH V6 01/14] perf/x86: Use event_base_rdpmc for the RDPMC userspace support kan.liang
2020-07-17 14:05 ` [PATCH V6 02/14] perf/x86/intel: Name the global status bit in NMI handler kan.liang
2020-07-17 14:05 ` [PATCH V6 03/14] perf/x86/intel: Introduce the fourth fixed counter kan.liang
2020-07-20 16:20   ` Peter Zijlstra
2020-07-20 18:22     ` Liang, Kan
2020-07-17 14:05 ` [PATCH V6 04/14] perf/x86/intel: Move BTS index to 47 kan.liang
2020-07-17 14:05 ` [PATCH V6 05/14] perf/x86/intel: Fix the name of perf METRICS kan.liang
2020-07-17 14:05 ` [PATCH V6 06/14] perf/x86/intel: Use switch in intel_pmu_disable/enable_event kan.liang
2020-07-20 16:22   ` Peter Zijlstra
2020-07-20 19:02     ` Liang, Kan
2020-07-17 14:05 ` [PATCH V6 07/14] perf/x86/intel: Generic support for hardware TopDown metrics kan.liang
2020-07-20 17:41   ` Peter Zijlstra [this message]
2020-07-20 18:11     ` Liang, Kan
2020-07-21  9:43   ` Peter Zijlstra
2020-07-21 14:05     ` Liang, Kan
2020-07-21 14:25       ` peterz
2020-07-17 14:05 ` [PATCH V6 08/14] perf/x86: Add a macro for RDPMC offset of fixed counters kan.liang
2020-07-17 14:05 ` [PATCH V6 09/14] perf/x86/intel: Support TopDown metrics on Ice Lake kan.liang
2020-07-21 12:40   ` Peter Zijlstra
2020-07-21 14:23     ` Liang, Kan
2020-07-21 14:31       ` peterz
2020-07-21 15:50         ` Liang, Kan
2020-07-21 17:38     ` Andi Kleen
2020-07-21 19:20       ` Peter Zijlstra
2020-07-17 14:05 ` [PATCH V6 10/14] perf/x86/intel: Support per-thread RDPMC TopDown metrics kan.liang
2020-07-17 14:05 ` [PATCH V6 11/14] perf/x86/intel: Disable sample-read the slots and metrics events kan.liang
2020-07-21 13:10   ` Peter Zijlstra
2020-07-21 16:07     ` Liang, Kan
2020-07-21 19:18       ` Peter Zijlstra
2020-07-22 19:26     ` Liang, Kan
2020-07-17 14:05 ` [PATCH V6 12/14] perf, tools, stat: Support new per thread TopDown metrics kan.liang
2020-07-17 14:05 ` [PATCH V6 13/14] perf, tools, stat: Check Topdown Metric group kan.liang
2020-07-17 14:05 ` [PATCH V6 14/14] perf, tools: Add documentation for topdown metrics kan.liang

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