topic Re: Kernel semaphore operations per second in Operating System - HP-UX

Kernel semaphore operations per second

Mark Chandler_1 — Tue, 28 May 2002 01:16:11 GMT

Hi,
I'm using some performance monitoring s/w on three HP/9000's I administer. The production box is a N4000-55. The s/w has been complaining about the numner of kernel semaphore operations per second going above a threshold of 100. I think that the threshold probably needs adjusting, but I can't find any documentation about what is a normal level of kernel semaphore ops/sec for a given spec of system. Does anyone have any information about what is a normal level for this metric?
Thanks in advance,

Mark C.

Re: Kernel semaphore operations per second

Michael Tully — Tue, 28 May 2002 01:57:21 GMT

Hi,

This metric and many others in your kernel are really determined by the application that is being used. What application are you running
and what are the current kernel parameters?

Here's how to get your current kernel parameters if you don't know how.

# cd /stand/build
# /usr/lbin/sysadm/system_prep -s test

Post a copy of this file 'test'

~Michael~

Re: Kernel semaphore operations per second

Mark Chandler_1 — Tue, 28 May 2002 02:06:55 GMT

Here's the file that I generated from kmtune -l. Does that produce enough of the same parameters?

Re: Kernel semaphore operations per second

Mark Chandler_1 — Tue, 28 May 2002 02:08:11 GMT

Ooops. I forgot to mention, the major application is Oracle 8.1.6/8.1.7.

Thanks.

Re: Kernel semaphore operations per second

Michael Tully — Tue, 28 May 2002 02:52:33 GMT

Hi Mark,

I would make the following changes to your
kernel for these. I don't run Oracle, but
I do run Informix, and I'm sure these will
help.

semmni 8192
semmns 16384
semmnu 4096
semume 128
semvmx 65535

Cheers
~Michael~