allocate a CPU for a process out of 4 CPUS

procfs · 12-30-2007, 10:15 PM

I have a multi processor machine in ML589 HP running RedHat AS3, is ti possible to dedicate one CPU out of four for a particular process. As this process is running slow

Thank you

Uncle_Theodore · 12-30-2007, 10:20 PM

Look at the taskset command. In RedHat, it's in the schedutils package, I think.

syg00 · 12-30-2007, 11:13 PM

Depends on what you mean by dedicate. Taskset will ensure the nominated task(s) will only run on the specified CPU(s). Other work can also run there.

To isolate workloads to given subsets of the CPUs I use cpusets. Also has the advantage of being able to classify future work entering the system. Works well.

procfs · 12-30-2007, 11:36 PM

What I ment was by dedicate, is to assign one out of four cpus just to handle this particular process (say process 123). This particular processor should handle only 123 process and other three will continue to performs as normal.

By the way by doing this will there be any draw basks.

Thanks

And I could not find cpuset command on my system though its a full installation

Uncle_Theodore · 12-30-2007, 11:46 PM

Well, with cpuset it's not that simple... First, it needs to be enabled in your kernel. Check with zcat /proc/config.gz | grep CPUSET
Then, you need to read this
http://www.mjmwired.net/kernel/Docum...on/cpusets.txt
and probably this
http://www.bullopensource.org/cpuset/

btmiller · 12-31-2007, 12:00 AM

If the task is CPU-bound, you might want to try decreasing the nice value before trying to dedicate it to a particular CPU. Note you'll need be root to set the nice value below 0 -- see the man pages of nice and renice for more information.

syg00 · 12-31-2007, 12:01 AM

Thx - saved me finding links; I'd ignore that bull one now-adays. They are still heavily involved, but you should just use the code in the mainline kernel.

It's still a work in progress too - major changes (amalgamation of code) came through in the last couple of -rc kernels. Doesn't affect cpusets already defined, but the doco changes significantly, and things are now handled via containers.
Still seems to work the same.

procfs · 12-31-2007, 12:28 AM

Thanks guys I'll try and update this