linux-kernel - Re: [PATCH v6 3/4] powerpc/lib: implement strlen() in assembly

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Date:   Tue, 12 Jun 2018 19:01:59 +0200
From:   Christophe LEROY <christophe.leroy@....fr>
To:     Segher Boessenkool <segher@...nel.crashing.org>
Cc:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, wei.guo.simon@...il.com,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v6 3/4] powerpc/lib: implement strlen() in assembly



Le 12/06/2018 à 16:53, Segher Boessenkool a écrit :
> On Tue, Jun 12, 2018 at 09:14:53AM +0000, Christophe Leroy wrote:
>> ---
>> Not tested on PPC64.
> 
> It won't be acceptable until that happens.  It also is likely quite bad
> performance on all 64-bit CPUs from the last fifteen years or so.  Or you
> did nothing to prove otherwise, at least.

Will it be as bad as the generic implementation which does it byte per 
byte ?

I don't have any 64 bits target, can someone test it using the test app 
I have added in selftests ?

Or should I just leave it as is for 64 bits and just do the 
implementation for 32 bits until someone wants to try and do it for PPC64 ?

Christophe

> 
>> + * Algorigthm:
> 
> Typo.
> 
> 
> Segher
>