[ltp] Re: Periodic freeze
John Magolske
linux-thinkpad@linux-thinkpad.org
Fri, 6 Jul 2012 00:01:36 -0700
* Elias Oltmanns <eo@nebensachen.de> [120703 17:22]:
> (2012-07-03) John Magolske <listmail@b79.net> wrote:
> [...]
>
> I have had occasion to observe sluggish responses too. (Un)fortunately,
> I can't reliably reproduce this state of affairs. One thing I noticed,
> though, is that top showed decidedly odd signs of activity. With no home
> work on my account, the box said it was something like 80% idle (or even
> less). Mind you, this is with no X server running at the time, or
> anything else worth mentioning for that matter. Instead, one or two of
> those kworker threads seemed to be anxious to make an eager impression.
> Since this happens only every once in a while on my machine (x200s) and
> I have to read up on domesticating those kworker threads first, I'm not
> sure I'll get to the heart of the matter too soon.
Thanks for writing this up, at least I know I'm not the only person
experiencing these issues. The only solution is to plug into AC.
Riding in on the train today, running on battery power, this display
on this X200s was freezing a couple times a minute, if not more. Now
that I'm plugged into AC, everything is nice & fluid
> > Also, after an `aptitude upgrade` last week I've begun to hear
> > periodic ~500ms gaps in audio while listening to music. In the past
> > I've *never* heard the audio skip. Not sure if this is related to the
> > display freeze-ups...who knows.
>
> This, too, is something I have observed here. By the way, it is my vague
> impression that this only happened after I upgraded to 3.2.21 or
> something thereabouts. But I did not really do extensive tests to verify
> that it does not happen on 3.2.14, for example, yet.
Do you recall which kernel you were running just prior to 3.2.21?
I'm on Debian Sid and saw this behaviour after a recent upgrade of
the 3.2.0-2-686-pae package (3.2.20-1).
I just now tried the 3.2.0-3-686-pae and 3.2.0-3-rt-686-pae (realtime)
kernels, (these are at 3.2.21-3), but got a kernel panic when I tried
to boot with them.
Anyone have suggestions for a Debian compatible, laptop-optimized
kernel? I'm thinking of giving liquorix a try next:
http://liquorix.net/
> Can you see anything suspicious in top when you experience those
> freezes on a supposedly idle machine?
For me these freezes last about 3-4 seconds max, so it's hard to
investigate too deeply. I take a look with top or htop now and then,
but haven't really been able to see any evidence of excessive CPU
usage. Here's a typical view:
top - 22:25:27 up 7 min, 1 user, load average: 1.01, 1.09, 0.64
Tasks: 123 total, 2 running, 121 sleeping, 0 stopped, 0 zombie
%Cpu(s): 5.8 us, 4.7 sy, 0.1 ni, 85.2 id, 4.2 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 3009508 total, 1090052 used, 1919456 free, 14464 buffers
KiB Swap: 0 total, 0 used, 0 free, 850420 cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
11304 john 20 0 84644 14m 3312 S 17.7 0.5 0:46.74 mpd
11305 john 20 0 13984 3908 2636 S 0.5 0.1 0:01.33 ncmpcpp
8099 root 35 15 4248 1948 828 S 0.4 0.1 0:01.43 preload
10369 john 20 0 6248 2608 1008 S 0.2 0.1 0:01.07 screen
30 root 20 0 0 0 0 S 0.1 0.0 0:00.55 kworker/1:2
1004 root 20 0 0 0 0 R 0.1 0.0 0:01.36 kworker/0:2
6701 root 20 0 7180 5620 4540 S 0.1 0.2 0:00.09 pads
15447 john 20 0 4948 1380 996 R 0.1 0.0 0:00.43 top
1 root 20 0 2176 712 608 S 0.0 0.0 0:06.04 init
2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd
3 root 20 0 0 0 0 S 0.0 0.0 0:00.03 ksoftirqd/0
6 root rt 0 0 0 0 S 0.0 0.0 0:00.00 migration/0
8 root rt 0 0 0 0 S 0.0 0.0 0:00.00 migration/1
10 root 20 0 0 0 0 S 0.0 0.0 0:00.03 ksoftirqd/1
11 root 20 0 0 0 0 S 0.0 0.0 0:00.12 kworker/0:1
13 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 cpuset
Regards,
John
--
John Magolske
http://B79.net/contact