Heavy processor usage while doing almost nothing

Wynd · 12-27-2003, 11:28 PM

Today in gkrellm I noticed that, while running gaim, an aterm and xmms (not playing anything), my user CPU usage is at 0% but the system is at ~15-20%! I do 'ps ax' and don't see anything unusual running, and top shows everything at 0-1%. What could be causing this? Things I've done recently are upgraded my kernel to 2.4.23 (Slackware package) and installed/removed Dropline Gnome. I think it may have something to do with this last one, because I'm pretty sure this didn't happen right after the kernel upgrade. Is there any way I can check to see what would make such a jump in CPU usage?

DavidPhillips · 12-27-2003, 11:30 PM

run top and see what processes are running.

Wynd · 01-03-2004, 01:29 PM

I did run top, it says everything is very low percent used.

Code:

top - 13:26:27 up  1:03,  1 user,  load average: 0.14, 0.14, 0.04
Tasks:  40 total,   1 running,  39 sleeping,   0 stopped,   0 zombie
Cpu(s):   0.0% user,  18.0% system,   0.0% nice,  82.0% idle
Mem:    515464k total,   191900k used,   323564k free,    14908k buffers
Swap:   514040k total,        0k used,   514040k free,   113236k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
  997 root      18   0 80124  14m 2776 S  0.3  3.0   0:10.18 X
    1 root       0   0   228  228  196 S  0.0  0.0   0:04.80 init
    2 root       9   0     0    0    0 S  0.0  0.0   0:00.21 keventd
    3 root      19  19     0    0    0 S  0.0  0.0   0:00.02 ksoftirqd_CPU0
    4 root       9   0     0    0    0 S  0.0  0.0   0:00.00 kswapd
    5 root       9   0     0    0    0 S  0.0  0.0   0:00.00 bdflush
    6 root       9   0     0    0    0 S  0.0  0.0   0:00.00 kupdated
   10 root      -1 -20     0    0    0 S  0.0  0.0   0:00.00 mdrecoveryd
   11 root       9   0     0    0    0 S  0.0  0.0   0:00.06 kjournald
   23 root       9   0     0    0    0 S  0.0  0.0   0:00.05 kjournald
   37 root       9   0     0    0    0 S  0.0  0.0   0:00.00 kapmd
   64 root       9   0   516  516  448 S  0.0  0.1   0:00.00 dhcpcd
   66 root       9   0   592  592  512 S  0.0  0.1   0:00.03 syslogd
   69 root       9   0   452  452  392 S  0.0  0.1   0:00.00 klogd
  152 root       8   0   568  568  500 S  0.0  0.1   0:00.00 crond
  154 daemon     9   0   620  620  552 S  0.0  0.1   0:00.00 atd
  164 root       9   0   504  504  452 S  0.0  0.1   0:00.00 apmd

It says 18.0% system. but according to top, none of the processes are doing anything! What is causing almost 400MHz of my processor to be constantly eaten up?

wapcaplet · 01-03-2004, 01:34 PM

I wouldn't worry about it

Why have your CPU sitting around doing nothing? As long as it's on, it might as well be doing stuff. System-maintenance related stuff runs all the time, usually with a low priority, so unless it's hurting your performance somehow, there's no cause for concern. top isn't always accurate about what is using CPU.

Wynd · 01-03-2004, 01:48 PM

I agree, it might as well be doing something, but what's bugging me is that i can't see what exactly it is doing, which is mainly what I want to know

david_ross · 01-03-2004, 02:05 PM

After running top - press "P" to sort by processor usage. Chcek your crontabs etc for jobs, some distros like redhat etc schedule jobs like an slocate database update.

Wynd · 01-03-2004, 03:05 PM

I pressed P in top, same thing. init shows a CPU time of 4.7, but currently it is at 0% usage. Nothing for cron/at. Apparently top only shows what is taking up the "user" part of the CPU usage, and not what's taking up the "system" part. Does anyone know of something that does show the system part (obviously not top)?

DavidPhillips · 01-03-2004, 03:32 PM

Mine seems to be right on the money. Not that I could tell if it wasn't.

CPU states: 0.2% user 1.4% system 0.0% nice 0.0% iowait 98.4% idle

Maybe it's a problem with gkrealm.

I would say it's more likely that while it's doing nothing, that it's doing nothing.

DavidPhillips · 01-03-2004, 05:42 PM

One possibility...

your top does not show iowait?

that is usually what gets most of the cpu statistics when it is high.

Wynd · 01-03-2004, 06:40 PM

No iowait, how can I add it?

DavidPhillips · 01-03-2004, 06:55 PM

top --version
procps version 2.0.11

Wynd · 01-09-2004, 08:35 PM

Ok, tell me if this makes sense. All this time I was at home over Christmas break, and when I come back to school with my computer and hook it up here, it's back to < 0.5% system use. What in the world would make that happen?

DavidPhillips · 01-09-2004, 11:02 PM

It's hard to say at this point, but I wish I would have been home on Christmas break.

I would try to update top in case it happens again. I have seen my iowait go way up there. Not really sure what caused it though.