At 09:09 PM 1/1/2009, Nephyrin Zey wrote: >Linux srcds has used a ton of CPU forever. The main frame loop is >optimized for a windows 66hz timer environment. Hence, linux servers >are 'perma-boosted' and chug inordinate amounts of CPU for minor FPS >increases, and they give us no variables to tweak the various sleep >times/calculations that impact this. SSE2 is still broken in linux >srcds. it also uses gettimeofday heavily, which was bad enough that >the l4d team specifically redid that part of the engine. The engine >uses 2-3% of the CPU entirely idle on kernels with a high response >rate (HPET/1000hz/other common things), which caused the l4d team to >put in a hibernation mode. > >The x86 binaries still use -fPIC >On other arches (amd64) it don't have any performance advantage due to >the necessary calls being there, but on x86 PIC clobbers a register >and causes call heavy binaries like srcds to use upwards of 6% of >their CPU time on thunks. Nvidia's linux OpenGL library, mpeg >decoders, etc, all use non-fPIC shared objects on x86. > >And yeah, SourceTV murders my server in CPU usage. I also noticed FPS >dips to the point where I had to fuck with the sleep timer to make >things go smoothly. I made a few threads about this but valve isn't >really all that interested. > >- Neph
64bit binaries would help. I've just finished porting vsyscalls back to 2.6.24 series (x86), and I see a minor drop under load. However, it doesn't fix the fact that the engine spends about 1500 cycles an idle loop with source tv on. I've also hacked in CLOCK_MONOTONIC support instead of gettimeofday.. why does a gameserver need nanosecond timestamps if everything is more or less estimated? I didn't think clobbering 1 additional register would make that much of a difference. Maybe on older gcc versions, but newer ones are better at it.. however, -fPIC will turn off optimizations that otherwise have to be enabled.. I think valve is using 2.9.5 on 1.6/source. The best long term solution is to use AMD64 binaries again, and then they could probably use fPIC without worry about clobbering %ebx.. G. "Monk" Stanley <gary at summit-servers dot com | gary at DragonflyBSD dot org> http://leaf.dragonflybsd.org/~gary "There currently are 7 different ways to get time from a computer. All of them can't agree on how long a second is supposed to be" -Me _______________________________________________ To unsubscribe, edit your list preferences, or view the list archives, please visit: http://list.valvesoftware.com/mailman/listinfo/hlds_linux
