Re: AES assembler optimizations

H. Peter Anvin
2004-08-10T19:51:37Z

Followup to: <20040809171231.GG2716@mea-ext.zmailer.org>
By author: Matti Aarnio <matti.aarnio@zmailer.org>
In newsgroup: linux.dev.kernel
>
> Usage of MMX inside the Linux kernel is like the usage of FP inside
> the Linux kernel: Can be done after jumping complex hoops, BUT NOT
> RECOMMENDED... (MMX in intertwined with FP hardware, after all.)
>
> You have to do lots of the MMXes in order to win after amortizing those
> necessary hoops... RAID-5 code does XOR via MMX code, under some
> conditions. ... where that happens to become a win.
>

It's not really that hard, you just have to have enough work to
amortize it over. The two metrics are: how much work do you get per
call, and how much work do you get before the next schedule().

-hpa