For the first reference, I have a WoW install. I haven't seen fps below 60 except in areas of the game where there are a lot of other players, but that was under OpenGL back before the latest patch. I haven't tried since Blizzard has disabled all high end settings in OpenGL mode for both Windows and Linux, and I've heard nothing but bad performance on D3D recently. I could give it a shot though. What is needed to make a kernel realtime other than adding CONFIG_SCHED_DEBUG and adding the sysctl settings?
Thanks Tom On Mon, Oct 25, 2010 at 6:26 PM, Dan Kegel <d...@kegel.com> wrote: > Hey folks, > I've run into two web sites that claim that the Linux kernel causes > performance > problems in particular games (see below). Anybody know of others? > > And has anybody found concrete improvements in performance > of a particular app (other than an audio workstation app) from using > a realtime kernel? > > Thanks! > - Dan > > First: > > http://wiki.archlinux.org/index.php/World_of_Warcraft#Kernel_Timing_Bug > says in a section dated September 2008: > "If you are having problems with choppy video every 15 seconds or so, > it is related to the kernel scheduler... > to fix, add CONFIG_SCHED_DEBUG=y to your kernel config, then set > kernel.sched_features=21 > kernel.sched_batch_wakeup_granularity_ns=25000000 > kernel.sched_min_granularity_ns=4000000 > in /etc/sysctl.cfg." > > Yikes. Any truth to that rumor? > > Second: > > http://hisouten.koumakan.jp/wiki/Linux_support#Resolved_bugs > says > > "The game runs too slowly > Symptoms: > Instead of running at about 60-62fps, like the game is supposed to, > it'll run closer to 53fps. This is not ideal. > The bug: > This is a Linux timing issue. The game runs a secondary timing thread > with THREAD_PRIORITY_TIME_CRITICAL, where it simply sleeps for 16ms > and sends events to the main thread to tell it that a new frame is > needed. On Linux the necessary timing accuracy is not available, so it > wavers between 16ms and 20ms. > The fix: > I hacked around this by setting the timer period to 14ms. This leads > to a steady 62-63fps. Which is close enough for use, really. For a > constant 60fps turn on vsync in your video drivers." > > >