On Sat, Apr 26, 2008 at 07:05:17PM -0700, Russ Allbery wrote: > gnubg supports optionally building with SSE support for increased speed in > the analytical engine. I have to date kept this disabled to not generate > binaries that might not run on all otherwise-supported Debian systems. > > However, a user mentioned that he thinks all chips that fall into the > amd64 architecture have SSE and hence adding -msse would be safe for the > amd64 build. Is that correct?
There is no need to enable -msse on amd64. It has always been on by default. > And in general are there any guidelines > about things like this? I assume that using -msse for the i386 build is > still out since we still support 486 chips. If you want to have different optimizations depending on the cpu, there are a two options I know of: - When you hace shared libraries you can put them in directories like /usr/lib/i686/sse/. The dynamic linker whould pick it up for you in that case. (I have no idea if it looks at i686/sse or not, but it looks at various other dirs, I can't find documentation for it.) - Use runtime detection of the cpu and select the best option yourself. > (I don't think the performance gain warrants the complexity of building > two binaries, although it is noticable.) It all depends if you think the performance gain is worth it. Kurt -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]