linux-kernel - Re: [PATCH 4/9] perf/x86/intel: Support hardware TopDown metrics

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Date:   Tue, 28 May 2019 15:43:54 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     kan.liang@...ux.intel.com
Cc:     acme@...nel.org, mingo@...hat.com, linux-kernel@...r.kernel.org,
        tglx@...utronix.de, jolsa@...nel.org, eranian@...gle.com,
        alexander.shishkin@...ux.intel.com, ak@...ux.intel.com
Subject: Re: [PATCH 4/9] perf/x86/intel: Support hardware TopDown metrics

On Tue, May 21, 2019 at 02:40:50PM -0700, kan.liang@...ux.intel.com wrote:
> @@ -3287,6 +3304,13 @@ static int core_pmu_hw_config(struct perf_event *event)
>  	return intel_pmu_bts_config(event);
>  }
>  
> +#define EVENT_CODE(e)	(e->attr.config & INTEL_ARCH_EVENT_MASK)
> +#define is_slots_event(e)	(EVENT_CODE(e) == 0x0400)
> +#define is_perf_metrics_event(e)				\
> +		(((EVENT_CODE(e) & 0xff) == 0xff) &&		\
> +		 (EVENT_CODE(e) >= 0x01ff) &&			\
> +		 (EVENT_CODE(e) <= 0x04ff))
> +

That is horrific.. (e & INTEL_ARCH_EVENT_MASK) & 0xff is just daft,
that should be: (e & ARCH_PERFMON_EVENTSEL_EVENT).

Also, we already have fake events for event=0, see FIXED2, why are we
now using event=0xff ?