Mailing List Archive: conserver uses 99% CPU

conserver uses 99% CPU

Nov 21, 2005, 2:45 AM

Post #1 of 3 (1975 views)

Hello.

We use conserver to share console access to devices. We use usual "console"
clients as well as home-made library to log data from console into the logs
of running test.

After using home-made library, conserver sometimes runs with 99% CPU.
Please note, that home-made library sometimes fails to close
connection to conserver propely, but server should not behave in such a way
if a client failed to do the things properly.

home-made library is very simple: it connects, sends "^Ec;", logs all
incoming data, tries to send "^Ec.", closes the socket.
I'm ready to provide any necessary information.

I've tried conserver 8.1.1 (default in Debian Sarge), 8.1.11 and 8.1.12,
there is no difference in their behaviour.

I've reported this problem to Debian bugtracker (339729), and Debian
maintainer Joergen Haegg advised me to forward my problem here.

Regards,
Alexandra.

--
Alexandra N. Kossovsky
OKTET Labs (http://www.oktetlabs.ru/)
Phones: +7(812)956-42-86(mobile) +7(812)428-67-09(office)
e-mail: sasha@oktetlabs.ru
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Re: conserver uses 99% CPU [ In reply to ]

bryan at conserver

Nov 21, 2005, 1:54 PM

Post #2 of 3 (1869 views)

Permalink

On Mon, Nov 21, 2005 at 01:45:35PM +0300, Alexandra N. Kossovsky wrote:
> After using home-made library, conserver sometimes runs with 99% CPU.

is there any way you can reliably reproduce this? this sounds similar
to another issue i've heard of (but can't reproduce) - sometimes i
wonder if it's something with a particular linux kernel or gcc version.
also, is it a single conserver process that uses all the cpu, or do all
processes spike to maximum?

> Please note, that home-made library sometimes fails to close
> connection to conserver propely, but server should not behave in such a way
> if a client failed to do the things properly.

that should be ok. the server is *supposed* to handle that. but
perhaps there is a bug somewhere.

> home-made library is very simple: it connects, sends "^Ec;", logs all
> incoming data, tries to send "^Ec.", closes the socket.
> I'm ready to provide any necessary information.

if you can provide a way to reproduce this, that would be best. aside
from that, if you run conserver with the -DDD flag, you'll get a ton of
output that will hopefully shed some light on what's going on when it
fails (but you'll need to get it to fail).

that's where i'd like to start...feel free to email me directly, and we
can post any findings (like a patch if we find the bug) to the list.

Bryan
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Re: conserver uses 99% CPU [ In reply to ]

cpz at tuunq

Nov 21, 2005, 2:07 PM

Post #3 of 3 (1858 views)

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Come to think of it, I've also seen conserver using 99% CPU (v8.1.0). Since
I've never been able to pin it on anything, I just kill/restart the server.

z!
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