linux-kernel - Re: [PATCH V2 5/6] x86/intel_rdt: Use perf infrastructure for measurements

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Date:   Thu, 6 Sep 2018 13:37:14 -0700
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     tglx@...utronix.de, fenghua.yu@...el.com, tony.luck@...el.com,
        mingo@...hat.com, acme@...nel.org, vikas.shivappa@...ux.intel.com,
        gavin.hindman@...el.com, jithu.joseph@...el.com,
        dave.hansen@...el.com, hpa@...or.com, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2 5/6] x86/intel_rdt: Use perf infrastructure for
 measurements

On 9/6/2018 1:29 PM, Peter Zijlstra wrote:
> On Thu, Sep 06, 2018 at 01:05:05PM -0700, Reinette Chatre wrote:
>> When I separate the above into the two functions it just becomes either:
>>                    rdpmcl(l2_hit_pmcnum, l2_hits_after);
>>                    rdpmcl(l2_miss_pmcnum, l2_miss_after);
>> or:
>>                    rdpmcl(l3_hit_pmcnum, l3_hits_after);
>>                    rdpmcl(l3_miss_pmcnum, l3_miss_after);
>>
> 
> Right, which is the exact _same_ code, so you only need a single
> function.
> 

>From my understanding it is not this code specifically that is causing
the cache misses but instead the code and variables used to decide
whether to run them or not. These would still be needed when I extract
the above into inline functions.

Reinette