linux-kernel - Re: [PATCH 1/2] perf vendor events: Add stepping in CPUID string for x86

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Date:   Thu, 15 Nov 2018 16:01:46 -0500
From:   "Liang, Kan" <kan.liang@...ux.intel.com>
To:     Jiri Olsa <jolsa@...hat.com>, acme@...nel.org
Cc:     mingo@...hat.com, peterz@...radead.org,
        linux-kernel@...r.kernel.org, namhyung@...nel.org,
        ak@...ux.intel.com
Subject: Re: [PATCH 1/2] perf vendor events: Add stepping in CPUID string for
 x86



On 11/15/2018 3:44 PM, Jiri Olsa wrote:
> On Wed, Nov 14, 2018 at 01:24:15PM -0800, kan.liang@...ux.intel.com wrote:
>> From: Kan Liang <kan.liang@...ux.intel.com>
>>
>> Perf tools cannot find the proper event list for Cascadelake server.
>> Because Cascadelake server and Skylake server have the same CPU model
>> number, which are used by perf tools to find the event list.
>>
>> The stepping for Skylake server is up to 4.
>> The stepping for Cascadelake server starts from 5.
>> The stepping can be used to distinguish between them.
>>
>> The stepping is added in get_cpuid_str().
>> The stepping information for Skylake server is updated in mapfile.csv.
>> A x86 specific strcmp_cpuid_cmp() function is added to handle two CPUID
>> formats in mapfile.csv, "vendor-family-model-stepping" and
>> "vendor-family-model".
>> - If a cpuid-regular-expression from the mapfile.csv using the new
>>    stepping format, a cpuid-string generated on the machine must include
>>    stepping. Otherwise, it is a mismatch.
>> - If the cpuid-regular-expression using the old non-stepping format,
>>    the stepping in the cpuid-string will be ignored.
>>
>> The script, which using environment string "PERF_CPUID" without stepping
>> on Skylake server, will be broken. If so, users must fix their scripts.
>>
>> Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
> 
> Reviewed-by: Jiri Olsa <jolsa@...nel.org>
>

Thanks Jirka,

Hi Arnaldo,

Are you OK with the patch?
If yes, I will go ahead to cleanup the *_cpuid_str() by moving them to 
header.c as promised. https://lkml.org/lkml/2018/11/15/929
The new patch will be on top of this patch.

Thanks,
Kan