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Message-ID: <20120815140016.76673zs818g2hagw@www.81.fi>
Date: Wed, 15 Aug 2012 14:00:16 +0300
From: Jussi Kivilinna <jussi.kivilinna@...et.fi>
To: Borislav Petkov <bp@...en8.de>
Cc: Johannes Goetzfried
<Johannes.Goetzfried@...ormatik.stud.uni-erlangen.de>,
Herbert Xu <herbert@...dor.apana.org.au>,
linux-kernel@...r.kernel.org, linux-crypto@...r.kernel.org,
Tilo Müller
<tilo.mueller@...ormatik.uni-erlangen.de>
Subject: Re: [PATCH] crypto: twofish - add x86_64/avx assembler
implementation
Quoting Borislav Petkov <bp@...en8.de>:
> On Wed, Aug 15, 2012 at 11:42:16AM +0300, Jussi Kivilinna wrote:
>> I started thinking about the performance on AMD Bulldozer.
>> vmovq/vmovd/vpextr*/vpinsr* between FPU and general purpose registers
>> on AMD CPU is alot slower (latencies from 8 to 12 cycles) than on
>> Intel sandy-bridge (where instructions have latency of 1 to 2). See:
>> http://www.agner.org/optimize/instruction_tables.pdf
>>
>> It would be really good, if implementation could be tested on AMD CPU
>> to determinate, if it causes performance regression. However I don't
>> have access to machine with such CPU.
>
> But I do. :)
>
> And if you tell me exactly how to run the tests and on what kernel, I'll
> try to do so.
>
Twofish-avx (CONFIG_TWOFISH_AVX_X86_64) is available in 3.6-rc1. For
testing you need CRYPTO_TEST build as module. You should turn off
turbo-core, freq-scaling, etc.
Testing twofish-avx ('async twofish' speed test):
modprobe twofish-avx-x86_64
modprobe tcrypt mode=504 sec=1
Testing twofish-x86_64-3way ('sync twofish' speed test):
modprobe twofish-x86_64-3way
modprobe tcrypt mode=202 sec=1
Loading tcrypt will block until tests are complete, after which
modprobe will return with error. This is expected. Results are in
kernel log.
-Jussi
> HTH.
>
> --
> Regards/Gruss,
> Boris.
>
>
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