On Fri, 2016-04-01 at 14:32 -0600, Jerry James wrote: > I am one of the maintainers of the ntl package, which is used by some > numeric applications (e.g., Macaulay2 and sagemath). Upstream > supports use of the PCLMUL instruction, the AVX instructions, and the > FMA instructions to speed up various computations. We can't use any > of those in Fedora, since we have to support a baseline x86_64. > > Well, that's kind of a downer. I could advertise that people with > newer CPUs ought to rebuild the ntl package for their own CPUs, but > what's a distribution for if people have to rebuild packages? I've > been looking for a way to automatically support more recent CPUs. > > [...] > Has anybody already thought this through? What's the best approach > to > take? For this package, the speedups are substantial, so this is > worth doing, if it can be done well.
In crypto libraries and gmp these optimizations are enabled using the cpuid information on runtime. That is, check the cpu capabilities on application/library load and override functions for specific functionality (e.g., with function pointers) on runtime. Is that something that can be used by ntl upstream? regards, Nikos -- devel mailing list devel@lists.fedoraproject.org http://lists.fedoraproject.org/admin/lists/devel@lists.fedoraproject.org
