How to measure waiting time in run queue?

Hello guys,

I am doing a performance analysis on one of our psystem. Most of time I am using Nmon analyser to do my trend graph. But I can't find any help with it. We are interesting in the time spend by tasks in Aix run queue.

After looking the Aix documentation, I am pessimist to find any straight metric in order to measure that time.

So I need your help :slight_smile:

Regards

Tech infos : Aix 6.1.6 on Power7

This would depend on what you are trying to collect.

One, classic approach, might be to use sar perhaps.

A different approach would be to use AIX Advanced Accounting.

If you are looking for a deep approach, and are looking at a specific process (rather than all processes) of a know PID and/or TID you could use various trace based tools (e.g., tprof, curt, etc) and/or trace and trcrpt . Rather than PID this could also be command name - there are too many options to name them all.

And, another option could be using probevue mechanism.

Hope this helps!

Hello,

Thank you for your answers. I should have specify my working environment :

Business app : SAP R3 on Oracle Cluster-ware
DB : Oracle 11g + RAC
FS : GPFS
OS : AIX 6.1
Servers : IBM psystem (Power7 CPU)

We are investigating divergence between real CPU consumption versus 'sap + rac oracle + gpfs' benchmarks in order to challenge our advanced support from SAP and Oracle.

By the way, I am not a AIX sysadmin neither I am an AIX expert. And unfortunately, I do not have hands over the system. To do something on the system, I have to ask our contractor in charge of. However, I understand thing well ... I think :slight_smile:

About your propositions :

First thing first, I want just graph this waiting time over the time no matter the process. I should read more carefully the SAR doc. I didn't know about the AIX advanced accouting system. Hence, I printed the doc and now I have to read it :slight_smile:

If we find something particuliar, I may go for a deep analysis but not with a real time trace I that is possible. We ran some CURT (3 time 1 minutes) and heavily impacted our 6000 users :x

Thank you again for your time. I will be certainly back with others questions and I hope results.

Regards

This also give me more to think about.

AIX 6.1 - which TL, how recently patched?
"Applications" - level and patch levels

How are you defining real CPU consumption?

Also,
Is the a shared, or dedicated processor partition?

If shared: how much entitlement; how many VP; how many active threads (normally); what is overal system utilization; how many activated processors. Partition utilization using the command

# lparstat 6 10 # simple command to review processor utilization for 60 seconds

please only outputs during "stress". "Idle" may also be presented, but only as a comparision.

And, what also helps - a ballpark figure of what you expected to see compared to what you are seeing.

Ah yes, almost forgot: Power7 Model and Firmware level.