linux-kernel - Re: [Patch v4 09/13] perf/x86/intel: Setup PEBS data configuration and enable legacy groups

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Message-ID: <fe19ce39-689c-419b-9073-7fcaacd2841f@linux.intel.com>
Date: Mon, 23 Jun 2025 09:55:48 +0800
From: "Mi, Dapeng" <dapeng1.mi@...ux.intel.com>
To: Peter Zijlstra <peterz@...radead.org>
Cc: Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo
 <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>,
 Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>,
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
 Kan Liang <kan.liang@...ux.intel.com>, Andi Kleen <ak@...ux.intel.com>,
 Eranian Stephane <eranian@...gle.com>, linux-kernel@...r.kernel.org,
 linux-perf-users@...r.kernel.org, Dapeng Mi <dapeng1.mi@...el.com>
Subject: Re: [Patch v4 09/13] perf/x86/intel: Setup PEBS data configuration
 and enable legacy groups


On 6/21/2025 5:43 PM, Peter Zijlstra wrote:
> On Fri, Jun 20, 2025 at 10:39:05AM +0000, Dapeng Mi wrote:
>
>> +		if (cpuc->n_pebs == cpuc->n_large_pebs)
>> +			index.split.thresh = ARCH_PEBS_THRESH_MUL;
>> +		else
>> +			index.split.thresh = ARCH_PEBS_THRESH_SINGLE;
>> +	if (cpuc->n_pebs == cpuc->n_large_pebs)
>> +		index.split.thresh = ARCH_PEBS_THRESH_MUL;
>> +	else
>> +		index.split.thresh = ARCH_PEBS_THRESH_SINGLE;
>> +/*
>> + * The largest PEBS record could consume a page, ensure
>> + * a record at least can be written after triggering PMI.
>> + */
>> +#define ARCH_PEBS_THRESH_MUL	((PEBS_BUFFER_SIZE - PAGE_SIZE) >> PEBS_BUFFER_SHIFT)
>> +#define ARCH_PEBS_THRESH_SINGLE	1
> Can we please do something like s/MUL/MULTI/ or so. My brain keeps
> trying to make it MULtiply and that doesn't really work.

Sure.