Re: [PATCH] [CRYPTO] cast6: inline bloat--

[Andi Kleen <andi@firstfloor.org>]

On Thu, Jan 10, 2008 at 08:27:46PM +1100, Herbert Xu wrote:
> On Thu, Jan 10, 2008 at 10:25:55AM +0100, Andi Kleen wrote:
> >
> > Then I don't think the patch should have been applied.
> 
> I disagree.  There isn't any evidence showing that the inlined version
> is significantly faster either.  In the absence of that, the version
> with the smaller size is preferable.

Just seems very risky to mess with cipher inner loops like that. Normally
people originally spent quite some effort tuning those; especially for
an AES candidate. Also putting quite a lot of function calls in there
doesn't seem right -- especially if frame pointer is enabled function
calls are not that cheap anymore. Also it messes up the register
allocation.

> Of course if anyone is keen enough about cast6 to provide benchmarks

If nobody is keen enough then the code could be just dropped
completely, couldn't it?

> showing that the inlined version is significantly faster then I'm
> happy to revert the patch.

There used to be papers with performance analysis of all the AES
candidates, but I cannot find them right now for CAST6. But I doubt
the code was written without proper thought.

-Andi