Tracking Most Frequently Used System Calls - Red Hat ENTERPRISE LINUX 5.4 - SYSTEMTAP BEGINNERS GUIDE Manual

22945 | 0 56949
0 | 0
4275 | 23140
4191 | 0 14405
22941 | 7908
4261 | 0
3695 | 0
3483 | 0 7206
4189 | 6916
1863 | 5767
2562 | 0 2881
4257 | 4255
4278 | 3876
4083 | 0 1331
3921 | 1603
4248 | 1591
3165 | 0 1441
29548 | 0 1440
1862 | 0
timeout.stp
Example 4.14.
You can increase the sample time by editing the timer in the second probe (timer.s()). The output
functioncallcount.stp
of
how many times each application performed each polling system call (over time).
"timeout.stp Sample Output"

4.3.5. Tracking Most Frequently Used System Calls

timeout.stp Section 4.3.4, "Monitoring Polling Applications"
from
are polling by pointing out which ones used the following system calls most frequently:
• poll
• select
• epoll
• itimer
• futex
• nanosleep
• signal
However, in some systems, a different system call might be responsible for excessive polling. If you
suspect that a polling application might is using a different system call to poll, you need to identify first
the top system calls used by the system. To do this, use topsys.stp.
topsys.stp
#! /usr/bin/env stap
#
# This script continuously lists the top 20 systemcalls in the interval
# 5 seconds
0 1
0 0 36414
0 0 1
0 0
1 0 62
0 0 2
0 0 0
0 0
0 0 2
0 0 0
0 1
0 0 1
0 0 60
0 1728
0 0 0
0 0 0
0 0
0 0
0 0 0
Sample Output
contains the name and UID of the top 20 polling applications, along with
contains an excerpt of the script:
Tracking Most Frequently Used System Calls
0 0 0| scim-bridge
0 0 0| swapper
0 0 0| mixer_applet2
0 0 0| scim-launcher
0 0 0| gnome-terminal
0 7622 0| escd
0 7622 0| gdm-binary
0 0 0| dhcdbd
0 0 0| scim-panel-gtk
0 0 0| iscsid
0 1438 0| pcscd
0 0 0| gnome-power-man
0 0 0| multiload-apple
0 0 0| Xorg
0 0 0| gam_server
0 0 0| nm-applet
0 0 0| xterm
0 0 0| httpd
0 1438 0| iscsid
helps you identify which applications
Example 4.14,
47