Quoting Borislav Petkov <bp@xxxxxxxxx>:
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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