Date: Thu, 01 Nov 2007 17:16:53 +0100 From: Rainer Hurling <rhurlin@gwdg.de> To: Kris Kennaway <kris@FreeBSD.org> Cc: Eugen Grosbein <eugen@kuzbass.ru>, freebsd-stable@freebsd.org, Oleg Derevenetz <oleg@vsi.ru> Subject: Re: kern/104406: [ufs] Processes get stuck in "ufs" state under persistent CPU load Message-ID: <4729FBF5.5010705@gwdg.de> In-Reply-To: <4728F747.6030607@FreeBSD.org> References: <027d01c8125c$73d4db80$c8c55358@delloleg><20071019220501.GL31826@elvis.mu.org> <20071020082724.GA87825@svzserv.kemerovo.su> <008d01c812f5$7aad62d0$eec55358@W2KOOOD> <4719F786.80708@gwdg.de> <47278BFA.90705@FreeBSD.org> <472843CC.8070604@nw-fva.de> <4728F747.6030607@FreeBSD.org>
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Kris Kennaway schrieb: > Rainer Hurling wrote: >> Thanks for your answer. >> >> Kris Kennaway schrieb: >>> Rainer Hurling wrote: >>>> Looking into PR kern/104406 it seems, that this describes exactly >>>> what I am experiencing on three of my systems over the last weeks. >>>> They are running FreeBSD 8.0-CURRENT (known as 7.0-CURRENT not long >>>> ago ;-) ). >>> >>> Actually it sounds nothing like it at all ;) >>> >>>> On these machines I often observe hangings, sometimes only a few >>>> seconds, on other times 20-30 seconds before input/output is back. >>>> This seems to happen when more extensive disk usage is needed >>>> (portupgrade, buildworld, browsing complicated websites etc.). >>>> During the hang even xterm is not responding any more, other >>>> (diskless) applications like xclock keep to continue. I have no >>>> panics, only UFS (and MSDOSFS) are mounted, no NTFS. About two >>>> months ago none of my systems showed these hangings. >>> >>> Is your system swapping? This is the usual cause of pauses during >>> high application (actually memory) load. >>> >>> Kris >> >> No, I am working with 2GB RAM, without swapping at all. >> >> In the meantime I tested the above described behaviour a little more. >> The hangings even appeared without using Xorg, only working on >> consoles under heavy disk usage (portupgrade etc.). > > OK, configure the system with the debugger and when it is "hung", break > to DDB and obtain the data requested in the developers handbook to try > and investigate what is going on. You may want to do this a few times > to make sure you capture a representative sample. > > Kris I hope to find some time on tomorrow for my first session in kernel debugging ;-) Am I right with chapter 'on-line kernel debugging using ddb'? What kind of information is most usefull? Rainer
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