[alanwww1]

Edit2: Found a workaround. Line 152 in xbmc/cores/dvdplayer/DVDCodecs/Video/DVDVideoCodecFFmpeg.cpp reads like this...

PHP Code:

int num_threads = std::min(8 /*MAX_THREADS*/, g_cpuInfo.getCPUCount()); 


Change it to this...

PHP Code:

int num_threads = std::min(8 /*MAX_THREADS*/, g_cpuInfo.getCPUCount()+2); 


and you should find it using much more CPU, also I found a fairly significant reduction in dropped frames.

I tried this and it actually helps a lot. Now i only have some few framedrops in the killa sample. The Dark Knight BD rip is actually playing without a problem.

I noticed a strange thing: Playing back the killa i checked in TOP pressing 1 then H to show threads that the two significant threads of xbmc.bin share almost evenly on CPU time BUT on top where i can see the utilizations, i still see uneven numbers. Like the cores were taking different amount of the two threads. One core is taking all of one thread and also some of the other thread and the other core just takes a few of one thread. It is really strange.

This compile option change might tell something to the Devs what we can play in config options to get better core share to reach the performance of the old kernels.

Screenshot of TOP with the strange situation (Threads 49%-45% ; CPUs 99% 13%)


I think the kernel tries to use as few cores as possible leaving the rest of the cores idle to make them downclockable. It is perfectly reasonable if we generally using the kernel for normal tasks. This way we have a 4 core or and 8 core processor used just as much core as it is nneded to fulfill a certain task. But with video decoding i think it's not good. We want to use the cores evenly loaded, better have the two main threads stayed exclusively on one a specific core.

Maybe there is a kernel option for this, how the user want to optimalize his cpu core usage. I think this could be the difference of Hardy and Intrepid kernel that Hardy did not have this so called "energy optimalized" cpu usage. (I already tried to disable powernowd and also speedstep in BIOS with no change)