[gamin] gam_server eats CPU

[Pete Zaitcev <zaitcev redhat com>]

Hi, guys:

I have a situation where an application makes small writes to a file.
In such a case, gam_server hogs the CPU. Here's a screen capture from
top(1):

top - 11:15:58 up  1:19,  4 users,  load average: 1.88, 0.71, 0.34
Tasks:  82 total,   1 running,  81 sleeping,   0 stopped,   0 zombie
Cpu(s):  9.7% us, 78.0% sy,  0.0% ni,  6.0% id,  0.0% wa,  5.3% hi,  1.0% si
Mem:    515688k total,   457868k used,    57820k free,    36652k buffers
Swap:   554232k total,        0k used,   554232k free,   259560k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 3729 zaitcev   25   0  3412 1232  856 S 80.3  0.2   1:35.21 gam_server
 3988 root      16   0  3576  404  348 S  4.3  0.1   0:06.84 cat
 3313 root      15   0 63572  16m 6228 S  1.7  3.3   0:42.10 X
 3450 zaitcev   16   0 38088  16m  10m S  1.7  3.3   0:10.03 nautilus
 3454 zaitcev   15   0 36680  14m 8624 S  0.7  2.8   0:14.44 gnome-terminal
 3444 zaitcev   16   0 13468 7328 6056 S  0.3  1.4   0:06.38 metacity
 3497 zaitcev   16   0 21336 9940 7700 S  0.3  1.9   0:03.52 wnck-applet
    1 root      16   0  1684  552  480 S  0.0  0.1   0:00.61 init

I run Fedora Core 3 with Nautilus enabled, and so I cannot just remove
Gamin and be happy. Does anyone have any ideas what do about this?

-- Pete

P.S. In case anyone is interested in details, this is what happened.
I was looking at some USB problems with usbmon and noticed that usbmon
drops about 0.7% packets. At first I thought it was something with SMM
BIOS or whatnot. But then I noticed that CPU is eaten by Gamin and
this apparently causes cat to starve sometimes. Usbmon produces a
stream of records which are captured with:
  cat /sys/kernel/debug/usbmon/1t > x.dump
It is rather lightweight, without any massive copying of data by the
kernel. E.g. the USB traffic itself creates much more copying and
memory and cache usage.