Re: [camellia-oss:00952] Re: [PATCH 5/5] camellia: de-unrolling, 64bit-ization

[Denys Vlasenko <vda.linux@googlemail.com>]

On Tuesday 13 November 2007 20:49, David Miller wrote:
> From: Denys Vlasenko <vda.linux@googlemail.com>
> Date: Tue, 13 Nov 2007 19:47:08 -0700
>
> > If CONFIG_CC_OPTIMIZE_FOR_SIZE is not an acceptable method,
> > do you have other ideas?
>
> Look at ways to make the code run faster without loop unrolling?

I did it. I noticed that key setup is mostly operating on 64-bit
quantities, and provided alternative implementation which
exploits that fact. It's smaller and faster.

However, after I've done that, the question still stands:
should I unroll the loop or not?

The situation we are in now is exactly the sutiation I want to
avoid:

On Wednesday 07 November 2007 06:22, Denys Vlasenko wrote:
> > Having two versions of the cdoe is unmaintainable.  So please
> > either decide that 5% is worth it or isn't.
>
> *I* am happy with 5% speed sacrifice. I'm afraid other people won't be.
>
> I just want to escape vicious cycle of -Os people arguing with
> -O2 people to no end. I don't want somebody to come later
> and unroll the loop again. And then me to come
> and de-unroll it again...
>
> It's better for everybody to recognize that both POVs are valid,
> and have provisions for tuning size/speed tradeoff by the user
> (person which builds the binary).

That's why I made a patch where unrolling can be enabled by CONFIG_xxx.

I will resubmit the patch without de-unrolling.
Meanwhile, I'd like to ask you guys to think about ways
to make size/speed tradeoffs selectable at build time.
--
vda