[X4U] how to view "pageouts?"

[David Ledger]

>From: zapcat <zapcat at speakeasy.net>
>On Jun 17, 2008, at 10:22 PM, David Ledger wrote:
>>  It doesn't gauge performance, it's a cause of poor performance. All it
>>  tells you about load is that you're asking your system to do more than
>>  you have the RAM for.
>
>well, if it "tells you" something, isn't that what a gauge
>does....informs you of something?

Well, in English English, 'gauge' means 'measure' or quantity 
information. Lots of pageouts shows you would probably benefit from 
more memory. That's not a measure, or anything like it. Just an 
indication. Of course if it's different in your English ...

Following on from other's comments, pageins are not a problem. They 
happen every time an application starts. If there's free memory, the 
page data just gets read in. One operation. Pageouts are done to 
innocent bystander processes when some other process needs to pagein 
and there's no free memory. It's an extra largeish procedure that has 
to be gone through just because memory is full. Pageouts are never 
done otherwise. (If memory-mapped file access is used, and I don't 
know if it is in OSX, and if those file read and write operations are 
counted into the same stats because they are identical at a low 
level, then pagein and pageout stats will be skewed).

David
  - currently in Las Vegas at HP Technology Forum, having just been to 
a presentation where exactly this was discussed as it applies to 
HP-UX.


-- 
David Ledger - Freelance Unix Sysadmin in the UK.
HP-UX specialist of hpUG technical user group (www.hpug.org.uk)
david.ledger at ivdcs.co.uk
www.ivdcs.co.uk