[ltp] Re: Periodic freeze

[Bert Haskins]

On 07/06/2012 03:01 AM, John Magolske wrote:
> * 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
>
I am plugged in to AC and this happens ( the grey-out effect ) even
when I'm not doing anything.
Even when typing this the system will just fail to respond and then
finally spit back all of the missed characters.
I can't get to top during the problem because the keyboard is not 
responding.

This is with 35-32 on a R60 and yes, it just missed the "a R60  ".
A six-second delay this time.
The problem "may" be somewhat related to how many tabs I
have open and/or how long FIrefox has been up without a
shutdown/restart.
Avgscan, memtest86, DFT, all report no problems.