topic Re: Performance Issue in Operating System - HP-UX

Performance Issue

fario — Wed, 04 Sep 2002 15:03:28 GMT

Hi all,

I know it is a difficult one :)

I have a CPU bottleneck in my machine. There is no memory pressure neither I/O. The machine executes a lot of scripts per second (that's the reason for that high nice value). The system CPU time is high (50-60%). How could I reduce this time?

I have seen in Glance in the CPU report (that I send you) that the vfault average is 21.7; is it normal? could it be reduced?

Thank you very much in advance.
Regards.

Re: Performance Issue

Sean OB_1 — Wed, 04 Sep 2002 16:35:13 GMT

If you have no memory, paging, or disk I/O issues then you need to find a way to execute your scripts faster.

What kind of scripts are they? By far the biggest waste of CPU time on most machines is poor coding.

So look at the scripts and see if there is anything you can do to decrease the work involved.

If they are interpreted scripts, thinking about writing them in a compiled language, such as C.

Re: Performance Issue

Pete Randall — Wed, 04 Sep 2002 16:43:19 GMT

With a CPU bottleneck, you really only have two choices: either reduce the load (re-design the application or offload some of the work) or increase the CPU resource (either more CPU's or faster ones).

Pete

Re: Performance Issue

Martin Johnson — Wed, 04 Sep 2002 17:35:34 GMT

Is there a way to combine scripts to run under one process? This would reduce system overhead. Of course, this also reduces what is run concurrently. You would need to find a balance here.

Another approach would be to rewrite the scripts in C. There would be less image activations.

HTH
Marty

Re: Performance Issue

harry d brown jr — Wed, 04 Sep 2002 17:43:04 GMT

I agree with the person that said reduce the number of scripts being run.

Secondly, if EMS is running, STOP it - its a PIG

Shutdown any unnecessary services, like NFS if you aren't using it!

Check your kernel parameters! MAKE SURE

timeslice is a 10 and not a 1 (ONE) !!!!!!!!!!

live free or die
harry

Re: Performance Issue

Wodisch — Wed, 04 Sep 2002 17:55:27 GMT

Hi Fario,

you could re-code your scripts to use "threads" instead of processes, you could try to use the sticky-bit on their codefiles, your could try to increase the kernel parameter "timeslice" (only by 1 or 2!).
But the "pageouts" do irritate me; there seems to be an memory bottleneck sometimes, perhaps when all those scripts are running concurrently? Stop all the services/daemons/processes you do not need.
Have thought about using "MWA" (HP OpenView MeasureWare Agent) to detect what really is going on? The "instant on" trial license should be sufficient...

Just my $0.02,
Wodisch