[FFmpeg-devel] looking for comparison of intrinsics vs hand written asm

[Attila Kinali]

Salut Guillaume,

On Fri, 30 Oct 2009 16:47:39 +0100
Guillaume POIRIER <poirierg at gmail.com> wrote:

> Now, I'm sure that you can get various amount of speed-up when writing the
> same vectorized code in ASM rather than with instrincs (I write "various"
> because based on my experience, the compiler will do a decent job dealing
> with your intrinsics, but it will fail miserably in some cases), but the
> real question is: how much of your time you want to spend on optimising your
> code?

The amount of time invested here is not of interest, as the whole
thing is an academic question. Ie it's about whether it's possible
or not given the current tools, not whether you need 100k trained
monkeys to perform it.

To give a little bit more background:
I attented today a talk on Spiral[1] and the question arrised from
them stopping at the c+intrinsics level instead of going down to
asm level (which IMHO shouldn't be much more difficult).

			Attila Kinali


[1] http://www.spiral.net/

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