linux-kernel - Re: [RFC][PATCH v2 00/21] x86/pti: Defer CR3 switch to C code

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Message-ID: <b63ec614-8a49-728d-aa61-76339378183f@oracle.com>
Date:   Wed, 18 Nov 2020 08:41:42 +0100
From:   Alexandre Chartre <alexandre.chartre@...cle.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
        x86@...nel.org, dave.hansen@...ux.intel.com, luto@...nel.org,
        peterz@...radead.org, linux-kernel@...r.kernel.org,
        thomas.lendacky@....com, jroedel@...e.de, konrad.wilk@...cle.com,
        jan.setjeeilers@...cle.com, junaids@...gle.com, oweisse@...gle.com,
        rppt@...ux.vnet.ibm.com, graf@...zon.de, mgross@...ux.intel.com,
        kuzuno@...il.com
Subject: Re: [RFC][PATCH v2 00/21] x86/pti: Defer CR3 switch to C code


On 11/17/20 10:26 PM, Borislav Petkov wrote:
> On Tue, Nov 17, 2020 at 07:12:07PM +0100, Alexandre Chartre wrote:
>> Some benchmarks are available, in particular from phoronix:
> 
> What I was expecting was benchmarks *you* have run which show that
> perf penalty, not something one can find quickly on the internet and
> something one cannot always reproduce her-/himself.
> 
> You do know that presenting convincing numbers with a patchset greatly
> improves its chances of getting it upstreamed, right?
> 

Well, it looks like I wrongfully assume that KPTI was a well known performance
overhead since it was introduced (because it adds extra page-table switches),
but you are right I should be presenting my own numbers.

Thanks,

alex.