How could I stop kworkers going crazy?

[a-wada]

Kworkers are going crazy and spoil OpenMp.

term-1 top,
term-2 cbm1 <- APP using OpenMP to calculate PI,
term-3 exec command for debugging

For about 5 minuts since APP started, kworkers were sane,
and APP used cpu 198% (dual core).
Screenshot : "please change 'a' -> 'h' in 'attp' following and browse in the other windows. I'd not posted more than 14 YET. "

attp://a-wada.s30.xrea.com/xxknl/Screenshot-2012-02-22-13-16-08.png

but, then kworkers woke up and ate cpu 80%+- incessantly
and APP's went down to 100%+-.

attp://a-wada.s30.xrea.com/xxknl/Screenshot-2012-02-22-13-17-41.png
attp://a-wada.s30.xrea.com/xxknl/Screenshot-2012-02-22-13-19-05.png
attp://a-wada.s30.xrea.com/xxknl/Screenshot-2012-02-22-13-35-57.png

referring to "7. Debugging" in "/usr/src/linux-source-3.0.0/Documentation/workqueue.txt"

a-wada:~/pai$ sudo su -c 'echo workqueue:workqueue_queue_work > /sys/kernel/debug/tracing/set_event'
[sudo] password for a-wada:
a-wada:~/pai$ sudo su -c 'cat /sys/kernel/debug/tracing/trace_pipe > out.txt'
^C
a-wada:~/pai$ ll out*
-rw-r--r-- 1 root root 23032133 2012-02-22 13:30 out.txt
a-wada:~/pai$ sudo su -c 'cat /proc/THE_OFFENDING_KWORKER/stack > out2.txt'
cat: /proc/THE_OFFENDING_KWORKER/stack: No such file or directory
a-wada:~/pai$ ll out*
-rw-r--r-- 1 root root 23032133 2012-02-22 13:30 out.txt
-rw-r--r-- 1 root root 0 2012-02-22 13:33 out2.txt

output of above commands

attp://a-wada.s30.xrea.com/xxknl/out.txt

source-code of "cbm1" & log when executed normally

attp://a-wada.s30.xrea.com/pailnx64/paicbm.c

Thanks in Advance.

###

After 8 hours since original post, I'd updated kernel to "3.0.0-16-29 ubuntu" expecting BUG-fix.
but it had not fixed my problem.

attp://a-wada.s30.xrea.com/xxknl/Screenshot-2012-03-10-00-42-13.png

kworkers were still going "CRAZY"

Please HELP

[a-wada]

This is a response to my question.

I could let "kworkers" be sane, by adding
" acpi=off " to kernel parameters, referring to
web: please change 'h' <- 'a' in 'attp' of NEXT

attp://morenews.blogspot.com/2011/08/when-kworkers-dont.html

But it makes "auto poweroff at shutdown" disable, Moreover,

perfomance of OpenMP Slow down to about 75% (without " acpi=off " 48% ).

Aren't these "BUGs of KERNEL or LINUX" ?

[a-wada]

Excuse me and very sorry everyone.
Kworkers were discharging their duties, nevertheless I accused them unjustly.

By my son's suggestion, I sensored the temperature of CPU. After 5 min APP started,
coretemps went up both to almost 100°C (threshold), and woke Kworkers up
to reduce the load, I think. With " acpi=off ", Kworkers kept being sane but
the performance had been degraded because of, maybe, high temperature.

Removing dust from fins of CPU-cooler kept Kworkers sane without " acpi=off "
and made the performance of OpenMP normal, too.

attp://a-wada.s30.xrea.com/xxknl/Screenshot-2012-03-17-11-28-08.png

[Rubberman]

I've experienced similar problem with system component (CPU or RAM) overheating. As a result, I monitor these issues continuously now, especially when I am running CPU/RAM-intensive processes. The lm_sensors package (and associated sensors command) help a lot in doing this in a server environment. On my workstation, I use a graphical system monitoring tool to do the same thing.