On 01/18/2013 08:13 AM, chronek wrote: > I have Debian testing distro with gcc 4.7.2 running on virtualbox where > assigned 8 cores and have some questions regarding gcc optimize flags. I > want run mencoder to filter big resolution video with uspp (that filter > calling snow encoder for encode/decode and avarage result (snow from ffmpeg > what is compiling with mencoder)). I use simple flags like -O3 -march=native > -mtune=native -mssse3 -fomit-from-pointer (cause it is virtual host it see > my i7 like core2 with max ssse3 instruction). > Is a way to compile for use more than one core/thread without changes in > sources, only just by add optimize flags? What flag would be best for > virtual host and speed up filtering? Is a way to check if it is memory or > cpu problem? (filtering with max quality filter on fullhd source is 1 thread > and 0.23 fps speed) GCC has auto-vectorization, which helps with some loops, but I doubt that it'll help you. http://gcc.gnu.org/projects/tree-ssa/vectorization.html Video encoding can benefit considerably from multiple cores, but it really needs the programmer to split the code into separate tasks. Andrew.
