From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <5d1c38ea5b178691f0031331c0af4ef9@quanstro.net>
From: erik quanstrom <quanstro@quanstro.net>
Date: Mon, 20 Jul 2009 08:26:48 -0400
To: 9fans@9fans.net
In-Reply-To: <c474560c799e51ecf948e9c09cb5a438@9grid.es>
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Subject: Re: [9fans] strange behaviour of ps under load
Topicbox-Message-UUID: 28b39402-ead5-11e9-9d60-3106f5b1d025

On Mon Jul 20 04:11:39 EDT 2009, gdiaz@9grid.es wrote:
> hello
>
> today i found 9grid plan9 under heavy load, stats reports load ~2000, syscall ~60000, context ~22000, i was trying to discover which proc has gone crazy, but i can't even complete a ps. I can do other operations, such as sending this email over drawterm, run stats, netstat, read the logs, etc. but i can't run ps, or any other /proc related tool, i can't kill/Kill/slay anything.
>
> I can ls /proc
>
> cpu% ls -l | wc -l
>     573

i've seen this problem before, without an unreasonable load.
it happened on a dual-processor machine.  since procopen()
requires p->debug, it stands to reason that somebody's got
p->debug qlocked and won't let go.

this is an old problem.  here are russ' thoughts
from 7 years ago.

http://9fans.net/archive/2002/02/350
http://9fans.net/archive/2002/02/360

- erik