Semaphore Usage

[Vito Sarducci]

How can I look at my semaphore usage from the previous 24 hours of time? What options do i have on 10.20 and 11.x?

Please advise?

Vito

[Sridhar Bhaskarla]

sar -m will give you semaphore usage.

sar -m 2 20 gives the the number of semaphore open calls averaged every 2 seconds for 20 iterations.

If you want it for the last day, you need to enable sar to collect the information for you.
Check the man page for sadc.
You just need to place an entry in your crontab like this
20 * * * * /usr/lbin/sa/sa1 1200 3
Create a directory /var/adm/sa to store the reports.

Then you can use sar -m with -s and -e options to get the information you want.

-Sri

PS: You can get better information of IPC usage if you have Glance+ installed.

-Sri

[Vito Sarducci]

Is IPC usage in glance the same as sar -m? What about Scopeux? What exactly can i extract from Scopeux that would assist me in finding this information?

I did not have sadc enabled and setup in cron but still want to see what happened last night?

Vito

[Sridhar Bhaskarla · Accepted solution]

If you are already collecting SCOPE/UX data, then you can easily pull out the information. Keep the following in a file called rept.

DATA TYPE GLOBAL

DATE
TIME

TBL_SHMEM_TABLE_UTIL
TBL_SEM_TABLE_UTIL
TBL_MSG_TABLE_UTIL

Now run extract with interactive mode and guide option and specify this file as the report file. You can specify the duration that you want and it will generate the out files called xfrdGLOBAL.asc and xfrsGLOBAL.asc depending on the type of data you specified.

-Sri

[Vito Sarducci]

Does the IPC Subsys column on the scopeux report have any correlation with Semaphore numbers?

Vito

[Sridhar Bhaskarla]

Shared Memory, Semaphores and Message streams are all the facilities in the IPC subsystem. So, APP_IPC_SUBSYSTEM_WAIT_PCT gives a feeling of how the application is managing the coordination internally with it's processes.

-Sri