On 17:07 Tue 27 Apr , Kip Warner wrote: > On Wed, 2010-04-28 at 00:32 +0200, Benjamin Drung wrote: > > > > The best solution would be autodetection of SSE2 on runtime. That can > > be > > done with a few lines of code. > > You're right, that can indeed be done with a few lines of code. e.g. > cpuid instruction. The problem is that you then have to perform a branch > every time you could potentially use hardware acceleration: a condition > for when, say, SSE2 is available, and another for a generic > implementation. > > It isn't ideal performance wise. Agreed. It's not the way we should go. > Perhaps for 32-bit x86 architectures where SIMD is required, I could > build the package for i686 and have it detect at runtime before said is > actually used, whether it is available or not. If it is not, raise a > user visible error and terminate. > > This method assumes the user knows that it is only supported on P4 or > later generation of x86. The point is that only few software use this kind of acceleration. If you really want to have SS2 and such activated, I suggest to do a rebuilt of all packages on your machine with your own architecture compilation options. We want to keep i386 or 'i486' compatible and not loose any performance due to performing a branch everytime you can activate an architecture optimization. And if we go through such a way, it will be hard for developers to maintain packages and it will require a lot of manpower. Greetings, -- ,''`. Xavier Oswald (xoswald@debian.org) : :' : GNU/LINUX Debian Developer <http://www.debian.org> `. `' GPG Key: 1024D/88BBB51E `- 938D D715 6915 8860 9679 4A0C A430 C6AA 88BB B51E
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