Re: Excessive stall times on ext4 in 3.9-rc2

From: Jiri Slaby
Date: Fri Apr 05 2013 - 18:18:24 EST


On 04/03/2013 12:19 PM, Mel Gorman wrote:
> On Tue, Apr 02, 2013 at 11:14:36AM -0400, Theodore Ts'o wrote:
>> On Tue, Apr 02, 2013 at 11:06:51AM -0400, Theodore Ts'o wrote:
>>>
>>> Can you try 3.9-rc4 or later and see if the problem still persists?
>>> There were a number of ext4 issues especially around low memory
>>> performance which weren't resolved until -rc4.
>>
>> Actually, sorry, I took a closer look and I'm not as sure going to
>> -rc4 is going to help (although we did have some ext4 patches to fix a
>> number of bugs that flowed in as late as -rc4).
>>
>
> I'm running with -rc5 now. I have not noticed much interactivity problems
> as such but the stall detection script reported that mutt stalled for
> 20 seconds opening an inbox and imapd blocked for 59 seconds doing path
> lookups, imaps blocked again for 12 seconds doing an atime update, an RSS
> reader blocked for 3.5 seconds writing a file. etc.
>
> There has been no reclaim activity in the system yet and 2G is still free
> so it's very unlikely to be a page or slab reclaim problem.

Ok, so now I'm runnning 3.9.0-rc5-next-20130404, it's not that bad, but
it still sucks. Updating a kernel in a VM still results in "Your system
is too SLOW to play this!" by mplayer and frame dropping.

3.5G out of 6G memory used, the rest is I/O cache.

I have 7200RPM disks in my desktop.

--
js
suse labs
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