Re: Oracle in an AIX LPAR

From: Rich Jesse <rjoralist3_at_society.servebeer.com>
Date: Wed, 4 Mar 2015 10:56:43 -0600 (CST)
Message-ID: <2723ea6a3e320bffa95a7e3f40604d57.squirrel_at_society.servebeer.com>



Hey John,

> Talking to our system guys, my understanding is that this LPAR has 4 CPU's
> dedicated, with 2 more allowed, so it is capped at 6. NMON shows 24 CPU's
> available. As I watch nmon, we see that the first thread on each CPU is
> typically running at 50% usage or better. I see cpu 9 and 3 getting some
> usage (second thread on cpu's 3 and 4), but other than that only the first
> thread on each CPU is being used. I assume the first thread is the
> primary. SMT 4 is being used.

Yup, the default scheduler will try to use a thread from each core before using more threads per core. So hypothetically, in SMT4, you might see CPU 0, 4, 8, etc. used first. This is (generally) a good thing.

> The processes getting CPU are all oracle<SID> (LOCAL=NO), so sqlnet
> connections.

And there's the key -- it's user processes. From there, you'll need to turn your attention to the Oracle instance to see what they're up to. I use EM12c to hopefully gain some visibility to what those processes are doing, but that's a whole different and elaborate topic...

Rich

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Received on Wed Mar 04 2015 - 17:56:43 CET

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