linux-kernel - Re: [PATCH V5 08/12] perf/x86/intel: Add Icelake support

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Date:   Wed, 10 Apr 2019 21:47:20 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     "Liang, Kan" <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 V5 08/12] perf/x86/intel: Add Icelake support

On Wed, Apr 10, 2019 at 02:22:21PM -0400, Liang, Kan wrote:
> > > That is, are there really bits we want to mask in there?
> > 
> > For instruction event, right, we don't need mask it.
> > I will change it.
> > 
> 
> Actually, we have to mask some bits here, e.g. ARCH_PERFMON_EVENTSEL_INT,
> ARCH_PERFMON_EVENTSEL_USR and ARCH_PERFMON_EVENTSEL_OS. Those bits will be
> set in hw_config().

Ah, bah, You're right. I misread and though we were comparing against
the user provided raw config.

> 
> Also, other filds, e.g the INV, ANY, E, or CMASK fields are not allowed for
> reduced Skid PEBS.

Sure, those are actually forced 0 with the existing thing.

I'll go fold smething like back in. Thanks!

> 
> diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
> index dae3d84..3fa36c9 100644
> --- a/arch/x86/events/intel/core.c
> +++ b/arch/x86/events/intel/core.c
> @@ -3463,6 +3463,9 @@ hsw_get_event_constraints(struct cpu_hw_events *cpuc,
> int idx,
>  	return c;
>  }
> 
> +#define EVENT_CONFIG(config)		\
> +	(config & (X86_ALL_EVENT_FLAGS | INTEL_ARCH_EVENT_MASK))
> +
>  static struct event_constraint *
>  icl_get_event_constraints(struct cpu_hw_events *cpuc, int idx,
>  			  struct perf_event *event)
> @@ -3472,7 +3475,7 @@ icl_get_event_constraints(struct cpu_hw_events *cpuc,
> int idx,
>  	 * Force instruction:ppp in Fixed counter 0
>  	 */
>  	if ((event->attr.precise_ip == 3) &&
> -	    (event->hw.config == X86_CONFIG(.event=0xc0)))
> +	    (EVENT_CONFIG(event->hw.config) == X86_CONFIG(.event=0xc0)))
>  		return &fixed_counter0_constraint;
> 
>  	return hsw_get_event_constraints(cpuc, idx, event);
> 
> Thanks,
> Kan