[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Scheduling problems


I'm having several problems concerning scheduling on my linux box. I'm running it as a server and therefore I'd like it to be as reliable as possible, but several niggling factors force me to reboot the box relatively often.

The biggest problem I have is if there is no CPU idle time (as reported by top(1)) processes take a very long time to start up, and sometimes even fail to start entirely. I can trigger this very easily and it is very reproducible. I tried to run the Distributed.net client at some point but it ground my system to a halt (even nice'd to 19). This prevents me from logging in using SSH to kill the offending process, or checking my email, or any other task that requires starting processes.

The next biggest problem is related to the above, I think. When I connect to my box using SSH, and the connection is broken somehow, the SSHd process takes up all the available CPU after just a couple of seconds. All I need to do to trigger this is to connect to the server, then kill the SSH client process. After a few seconds, the server process reaches 99.9% CPU usage:

[bootc@arcadia bootc]$ pa | grep notty
bootc 24408 99.9 0.4 10688 3928 ? R 14:15 0:38 sshd: bootc@notty bootc 24448 0.0 0.0 1576 496 pts/7 S+ 14:16 0:00 grep notty

I'm running Debian Sarge on Linux 2.6.5 with no special patches. The machine is a Shuttle XPC with an Athlon XP2000+ and 1GB of RAM. The problems have occurred for as long as I can remember, definitely all along the 2.6 kernel series, but most probably before then too.

Thanks for any pointers people can give me...


Chris Boot

Reply to: