Re: QPRCMLTTSK system value

Hi Pete

I can't find anything that connects the setting of this system value directly to Java performance. I googled for "qprcmlttsk java".

It is shipped as set to '1'. I understand that sometimes Linux won't run when this is set to '1' (from 2002 article by Larry Loen, I believe).

Since the default is to have it turned on, I'd say it's best to leave it that way. That is the gist of an InfoCenter article on when to use this feature. It appears that things should not go more slowly when this is on, but you won't gain double the speed from the 2 paths in a CPU in earlier processor since NorthStar. POWER7 seems now to support 4 hardware threads on a core.

This is only a guess based on my reading, but I'd say it probably can't hurt to leave it on. Unless you have Linux in a partition.

Vern

Pete Hall wrote:

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I'm considering setting QPRCMLTTSK to '1' on an 825 (V540) for improved
Java performance. Does anyone have any horror stories about it? Heavy
batch processing occurs on this system each night, and there's still a
significant single threaded interactive/batch mix during the day. Since
this setting is inherited from the controlling partition on 7xx and 8xx
machines, I can't test it on the dev LPAR first.

- --
Pete Hall
pete@xxxxxxxxxxxxxx
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