Re: [PATCH] crypto: twofish - add x86_64/avx assembler implementation

From: Borislav Petkov
Date: Wed Aug 15 2012 - 05:28:03 EST


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.

HTH.

--
Regards/Gruss,
Boris.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/