Messages in this thread | | | Date | Tue, 06 Nov 2012 17:11:02 +0100 | From | Ove Karlsen <> | Subject | Re: Help low-jitter man. |
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Den 06.11.2012 16:40, skrev Ove Karlsen: > Heya, it`s me again. I am getting my low-jitter E5 computer, soon, and I > have done all the tweaks I can think of with the kernel. > > I was wondering if anyone had anything to add, any good technical > opinion on reducing jitter (for workstation desktop/OpenGL). > > I have a kernel with "low latency desktop" enabled. And edited > Kconfig.hz to 90. > idle=poll and tick_skew=1 in boot options. > Compile a shaved local kernel by doing "make localmodconfig" from a full > distro kernel. > (Also turned of high_res_timers, to get 90hz) > > CFS granularity 1158500nS. (Current setting is a bit high) > Reniced X to -20, to prevent X being a bottleneck. > Remove 60hz limit in doom 3, to avoid timing jitter. > http://paradoxuncreated.com/tmp/AutoExec.cfg > > Some nvidia-specific stuff on my blog aswell : > http://paradoxuncreated.com/Blog/wordpress/?p=2268 > > A lot of people think SLAB has lower jitter than SLUB etc, aswell, and > some tuning with regards to what kernel options execute the least code, > least background activity can be done. Opinions? > > I use SLUB currently, and have turned off mem-compaction. > And probably all kinds of debugging, counters and tracers. > > RCU boost to 99. > > I think I have collected most the relevant data for a low-jitter linux > config. but in case there is additional information, I would love to > hear it. > > Also ACPI on or off seems to be varying opions on. Some state ACPI > removes SMI`s? I don`t know what is true here, and knowing that some > recommend 10000hz timer for "low-jitter" (which is going the completely > wrong way) I would like to hear your opinion on this aswell. > > Also approaching a transparent OS, with realtime-threads is interesting. > Such as running maintask (optionally + depencies) as realtime. > Unfortunately it doesn`t seem to work so well with standard FIFO. Do you > think deadline could help this? Accurate 0.95ms of 1ms would be > interesting to try. > > Also if anyone knows a linux-distro with the same philosophy throughout > the OS, I would be interested to know about it. >
Also have anyone given any thoughts to vsynced HZ? And also even possibly dividing subhz off that, or more hz counters if neccesary.
-- Fred være med deg / Peace Be with You, Ove Karlsen http://www.paradoxuncreated.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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