This is the mail archive of the
systemtap@sourceware.org
mailing list for the systemtap project.
Re: Script to look for system call errors
- From: Mark Wielaard <mjw at redhat dot com>
- To: systemtap at sources dot redhat dot com
- Date: Thu, 02 Apr 2009 11:50:06 +0200
- Subject: Re: Script to look for system call errors
- References: <49D377A8.8090005@redhat.com>
Hi Eugene,
On Wed, 2009-04-01 at 22:18 +0800, Eugene Teo wrote:
> Last night I was working on a script to look for system call errors.
> This is particularly useful for identifying misbehaving userspace
> applications. The script prints out useful information about the top 20
> errors every 5 secs.
>
> With the script, I found out that mixer_applet2 wakes up very
> frequently[1], gnome-panel tries to add a collection of watches every
> second for files that do not exist, hald tries to open some
> battery-related sysfs files over and over again even though I am running
> the script in a virtual machine. mjw has a couple of interesting
> observations with the script as well.
Yeah, good script! It would be nice if you could set the timeout and
number of output lines. Some observations that immediately sprung up
from using it:
- I am using a XMCDP session and gnome-screensaver continuously seems to
do non-blocking reading to the server:
sys_read gnome-screensav 2048 870 11 (EAGAIN) 3, 0x00000000020c5504, 4096
- The gnome panel issue you already mentioned, every second I see:
sys_inotify_add_watch gnome-panel 2049 1 2 (ENOENT) 18, "/home/mark/.config/menus/settings-merged", 16789454
sys_inotify_add_watch gnome-panel 2049 1 2 (ENOENT) 18, "/home/mark/.config/menus/preferences-merged", 16789454
sys_inotify_add_watch gnome-panel 2049 1 2 (ENOENT) 18, "/etc/xdg/menus/system-settings-merged", 16789454
sys_inotify_add_watch gnome-panel 2049 1 2 (ENOENT) 18, "/home/mark/.config/menus/system-settings-merged", 16789454
sys_inotify_add_watch gnome-panel 2049 1 2 (ENOENT) 18, "/etc/xdg/menus/server-settings-merged", 16789454
- The multiload-applet seems to use some ioctl and stat on my xen block
device and lvm volume device those don't support/exist, but it keeps
trying anyway up to 30 times per second:
sys_ioctl multiload-apple 2127 30 95 (EOPNOTSUPP) 19, 35585, 0x00007fff8d47f810
sys_ioctl multiload-apple 2127 6 99 (EADDRNOTAVAIL) 19, 35093, 0x00007fff8d47f810
sys_open multiload-apple 2127 6 2 (ENOENT) "/sys/block/xvdb/xvdb1/stat", O_RDONLY
sys_open multiload-apple 2127 6 2 (ENOENT) "/sys/block/mapper/VolGroup/mapper/VolGroup00-LogVol00/stat", O_RDONLY
- During a window resize metacity continuously tries to load a
non-existing cursor icon files that don't exist during the drag:
sys_open metacity 2047 17 2 (ENOENT) "/home/mark/.icons/Bluecurve/index.theme", O_RDONLY
sys_open metacity 2047 17 2 (ENOENT) "/home/mark/.icons/Bluecurve/cursors/left_side", O_RDONLY
sys_open metacity 2047 17 2 (ENOENT) "/home/mark/.icons/default/index.theme", O_RDONLY
sys_open metacity 2047 17 2 (ENOENT) "/home/mark/.icons/default/cursors/left_side", O_RDONLY
sys_open metacity 2047 17 2 (ENOENT) "/usr/share/pixmaps/default/cursors/left_side", O_RDONLY
sys_open metacity 2047 17 2 (ENOENT) "/usr/share/icons/default/cursors/left_side", O_RDONLY
And that was just playing with the script for 30 seconds. Lots of
interesting stuff should come out of this. Thanks for writing it.
BTW. Frank upded the limit you were hitting in 76eb4a PR4105: support up
to 9 (up from 5) array index dimensions.
Cheers,
Mark