Tuesday November 21, 2006 Weblog
Tuesday November 21, 2006 Caps revised
It was quite some time ago since I provided an update on CPU caps. A lot have happened since then. I was working on finishing the implementation and now the development phase is complete. So, I went back to the documentation and updated both the design document and the implementation description.
The major change is the addition of the observability hooks to the project. I used the nice kstat(1M) facility to provide some visibility into CPU caps inner workings.
First of all I created a project for myself by adding a line in /etc/project:
user.akolb:1234:Projects for akolb:*:*:project.cpu-cap=(privileged,50,none)
I could then join the project:
$ newtask -p akolb -c $$
$ ps -o user,project,comm -p $$
USER PROJECT COMMAND
akolb akolb bash
Now I started a process that does nothing but consumes CPU cycles:
$ while [ 1 ]; do true; done
Running prstat -J 1 showed that my project uses 25% of the system
(50% of a CPU on a 2-CPU system gives 25% total). Now I use kstats to verify how
am I doing with caps:
$ kstat caps
module: caps instance: 0
name: cpucaps_project_1234 class: project_caps
above_sec 278
below_sec 97
flags 10
nwait 1
usage 49
value 50
The design document provides additional information on observing CPU caps with DTrace and provides a couple of interesting examples. It allows us to pinpoint CPU caps effect for specific process.
[ Technorati: Scheduler, Solaris ]
( Nov 21 2006, 06:25:03 PM PST ) PermalinkComments:
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