kern/104406: [ufs] Processes get stuck in "ufs" state under persistent CPU load

[Rainer Hurling]

It looks like that Marek Blaszkowski in his new thread on freebsd-amd64@

http://www.nabble.com/forum/ViewPost.jtp?post=13513077

is describing the same system hangings. He founds some strange behaviour 
with 'sync' of harddiscs. Perhaps this is a step towards the cause of 
hangings?

Regards,
Rainer


Rainer Hurling schrieb:
> 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.).
> 
> Rainer