vmstat 'b' (disk busy?) field keeps climbing ...
Kostik Belousov
kostikbel at gmail.com
Sat Jun 24 19:09:19 UTC 2006
On Sat, Jun 24, 2006 at 09:52:03PM +0300, Kostik Belousov wrote:
> On Sat, Jun 24, 2006 at 02:57:27PM -0300, Marc G. Fournier wrote:
> > On Sat, 24 Jun 2006, Kostik Belousov wrote:
> >
> > >On Sat, Jun 24, 2006 at 11:55:26AM +0400, Dmitry Morozovsky wrote:
> > >>On Sat, 24 Jun 2006, Marc G. Fournier wrote:
> > >>
> > >>MGF> > 'b' stands for "blocked", not "busy". Judging by your page fault
> > >>rate
> > >>MGF> > and the high number of frees and pages being scanned, you're
> > >>probably
> > >>MGF> > swapping tasks in and out and are waiting on disk. Take a look at
> > >>MGF> > "vmstat -s", and consider adding more RAM if this is correct...
> > >>MGF>
> > >>MGF> is there a way of finding out what processes are blocked?
> > >>
> > >>Aren't they in 'D' status by ps?
> > >Use ps axlww. In this way, at least actual blocking points are shown.
> >
> > 'k, stupid question then ... what am I searching for?
> >
> > # ps axlww | awk '{print $9}' | sort | uniq -c | sort -nr
> > 654 select
> > 230 lockf
> > 166 wait
> > 85 -
> > 80 piperd
> > 71 nanslp
> > 33 kserel
> > 22 user
> > 10 pause
> > 9 ttyin
> > 5 sbwait
> > 3 psleep
> > 3 accept
> > 2 kqread
> > 2 Giant
> > 1 vlruwt
> > 1 syncer
> > 1 sdflus
> > 1 ppwait
> > 1 ktrace
> > 1 MWCHAN
> >
> > According to vmstat, I'm holding at '4 blocked' for the most part ...
> > sbwwait is socket related, not disk ... and none of the others look right
> > ...
> I would say, using big magic cristall ball, that you problems are
> not kernel-related. I see only too suspicious points:
>
> 1. high number of pipe readers and waiters for file locks. It may be
> normal for your load.
>
> 2. 2 Giant holders/lockers. Is it constant ? Are the processes holding/waiting
> for Giant are the same ?
>
> Anyway, being in your shoes, I would start looking at applications.
>
> Ah, and does dmesg show anything ?
And another question: what are the processes in the state "user" ?
I never see that state. More, search thru the sources does not show
what this could be.
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