Re: 'autogroup' sched code KILLING responsiveness
From: Mike Galbraith
Date: Fri Jan 21 2011 - 22:22:45 EST
On Fri, 2011-01-21 at 16:39 -0600, Michael Witten wrote:
> On Fri, Jan 21, 2011 at 16:27, Mike Galbraith <efault@xxxxxx> wrote:
> > On Fri, 2011-01-21 at 10:20 -0800, Michael Witten wrote:
> >> Bisecting shows that this commit:
> >>
> >> 5091faa449ee0b7d73bc296a93bca9540fc51d0a
> >> sched: Add 'autogroup' scheduling feature: automated per session task groups
> >> Date: Tue Nov 30 14:18:03 2010 +0100
> >>
> >> is the reason that my computer has become unusable.
> >>
> >> With that code in place, a resource-intensive activity (such as
> >> compiling the Linux kernel) causes my computer to become
> >> unresponsive for many seconds at a time; the entire screen
> >> does not refresh, typed keys are dropped or are handled very
> >> late, etc (even in Linux's plain virtual consoles).
> >
> > That's not what I'm experiencing with a UP kernel...
>
> Before I try to gather any data, I'd like to point out that the
> problem disappears when I disable CONFIG_SCHED_AUTOGROUP (General
> setup -> Automatic process group scheduling).
>
> Do you have it disabled?
No, ff I did, mplayer wouldn't be able to get more than 1% cpu.
top - 22:34:38 up 33 min, 22 users, load average: 104.07, 101.73, 78.13
Tasks: 675 total, 101 running, 574 sleeping, 0 stopped, 0 zombie
Cpu(s): 95.2%us, 4.8%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ P COMMAND
6770 root 20 0 401m 79m 29m R 46.9 1.0 3:22.66 0 mplayer
6100 root 20 0 449m 94m 18m S 2.9 1.2 1:33.82 0 Xorg
7486 root 20 0 374m 46m 17m S 2.9 0.6 0:54.02 0 konsole
-Mike
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