Messages in this thread | | | Date | Sat, 1 Mar 2008 03:59:53 +0300 | From | "Alexey Zaytsev" <> | Subject | Re: printk timestamps jumping back and forth in 2.6.25-rc. |
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On Sat, Mar 1, 2008 at 3:42 AM, Alexey Zaytsev <alexey.zaytsev@gmail.com> wrote: > > On Fri, Feb 29, 2008 at 10:45 PM, Ingo Molnar <mingo@elte.hu> wrote: > > > > * Alexey Zaytsev <alexey.zaytsev@gmail.com> wrote: > > > > > > > > > On Thu, Feb 28, 2008 at 11:16 PM, Ingo Molnar <mingo@elte.hu> wrote: > > > > > > > > * Ingo Molnar <mingo@elte.hu> wrote: > > > > > > > > > > Anything else I can do? > > > > > > > > > > yes, please test the patch below - does it fix the problem? > > > > > > The patch worked well, thanks > > > > > > I still observe some uneven mouse behaviour during compilations (linux > > > kernel, make -j 6), like, when I slowly move the mouse, it would stop > > > for a split of a second every few seconds (the intervals are not > > > equal). On 2.6.23/24 it works very smooth. Of course, I can't say that > > > the scheduler is to be blamed. It was only my assumption because I > > > thought I might be confused by the non-monotinic time, which I see is > > > not the case. Any ideas, how to debug this? > > > > could you try latencytop, what does it say, what type of scheduler (and > > other) delays are there? > > > > I'm not sure I fully understand how to use this tool. > There are clearly two possible options to the utility, > --unknown and -d, but I still have no idea what they do.. > > Does the latencytop-0.3 actually work? I my case the upper half of the > window is always empty. The lower half shows always one line, like > > Scheduler: waiting for cpu \t \t \t \t $some_val $some_val > > The two values are always identical. > > In the 2.6.24 case, the values for Xorg are always around 20 ms > when a make -j 6 is runig in parallel. For the 2.6.25 the > values jump from 100 ms to over 1000 ms. > > Later I mounted a tmpfs and run the compilation (from root) there > (swap turned off). This time the Xorg latency was usually less then > 30 ms, but the gnome-terminal (running from an other user) was not > that lucky with latencies around 500-1000 ms. Now I ran the same compilation > from user, and the latencies came back to what I observed before, with > gnome-terminal being about 30-50 and Xorg jumping from 100 to now > over 2000. The latencytop and some daemons runnig as different users > also had comparable latencyes. > > Yes, fair group scheduler enabled, the config can be seen here: > http://romomatic.osuosl.org/share/xl0/config-2.6.25-rc3 > > I"ll now recompile with fair group scheduler disabled, just to be sure. >
Yes, with the group scheduler disabled, the latencies for both Xorg and gnome-terminal do net exceed 15 ms. And the mouse is also smooth.
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