Bug#572746: libm: sinf/cosf performance is awful on amd64
On Mon, Mar 08, 2010 at 12:17:41AM +0100, Jerome Vizcaino wrote:
> Ok about the patches : there had to be a reason for those not to be merged
> upstream.
Also I think they have never been submitted upstream. They are from
2002...
> Some of my co-workers noticed the performance improvement when binding values
> between -pi and pi but the thing is, this kind of trick do not need to be
> applied when on 32 bits systems... Libm's behavior is not really arch-proof in
> terms of performance which is a bit confusing (and I would expect 64 bit being
> better than 32 bits when dealing with maths... :(
cosf/sinf is actually twice faster on 64-bit than on 32-bit in normal
cases, but can be a lot slower in the cases that concern you.
> Have you tried pushing your code upstream ? Maybe this would be useful for
> future versions.
>
It's currently not clean enough to be send upstream. I'll try to send it
upstream, but I don't have to much hope.
--
Aurelien Jarno GPG: 1024D/F1BCDB73
aurelien@aurel32.net http://www.aurel32.net
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