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@greysector.net>: > > 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.