Re: SIMD vs no SIMD on i686 (was: [Bug 3975] executable stack flag prevents use of libx264.so.148 with selinux in enforcing mode)

2016-07-19 2:55 GMT+02:00 <dominik(a)greysector.net&gt;: > Hello, Sérgio. > > On Tuesday, 19 July 2016 at 02:35, RPM Fusion Bugzilla wrote: >> https://bugzilla.rpmfusion.org/show_bug.cgi?id=3975 >> >> --- Comment #4 from Sérgio Basto <sergio(a)serjux.com&gt; 2016-07-19 02:35:19 CEST --- >> (In reply to comment #3) >> > I'll take a look at this. Could you try running execstack -c on the installed >> > library in the meantime? >> >> Be my guest , in meantime I read your thread on packaging Mailing list about >> sse3 , I'd like understand if we need 2 builds for i686 ... one with sse2 other >> without it, can you give us your opinion ? > > The only real concern here are applications linked against libx264, > which someone might want to run on low-end hardware, because I don't > think anyone would want to encode anything to H.264 on non-SSE2 capable > CPU (i.e. Pentium 3 or Athlon XP and older). Considering last non-SSE2 > CPUs went out of production about 8 years ago, I think it's fairly safe > to assume that the impact of doing SSE2-only builds would be negligible, > if any. I'm okay to have a SSE2 only build for single binaries such as pcsx2 for the following reasons: - pcsx2 requires more CPU resources than barely capable sse2 CPU anyway. - Using sse2 will allow older but sse2 capable CPU to run. - Runtime test has to be made to avoid crash and notify user if the CPU don't have sse2. But for libraries it's not possible to assume a given usage and ensure users notification. I expect you can have webcam app to encode to h264 low profile just fine using x264 even on non-sse2 capable cpu. It's expected not to crash here. So I don't understand why this discussion raised up again, but I'd like not to more anything in i686 that will made some corner case users to crash.