Re: removing mm->rss and mm->anon_rss from kernel?

From: Martin J. Bligh <mbligh_at_aracnet.com>
Date: 2004-11-08 03:11:24
>> I would've thought SGI would be more worried about this kind of thing
>> than anyone else ... what's going to happen when you type 'ps' on a large
>> box, and it does this for 10,000 processes?
> 
> Yes but I think this is preferable because of the generally faster
> operations of the vm without having to continually update statistics. And
> these statistics seem to be quite difficult to properly generate (why else
> introduce anon_rss). Without the counters other optimizations are easier
> to do.
> 
> Doing a ps is not a frequent event. Of course this may cause
> significant load if one does regularly access /proc entities then. Are
> there any threads from the past with some numbers of what the impact was
> when we calculated rss via proc?

Doing ps or top is not unusual at all, and the sysadmins should be able
to monitor their system in a reasonable way without crippling it, or even
effecting it significantly.
 
>> If you want to make it quicker, how about doing per-cpu stats, and totalling
>> them at runtime, which'd be lockless, instead of all the atomic ops?
> 
> That has its own complications and would require lots of memory with
> systems that already have up to 10k cpus.

Ummm 10K cpus? I hope that's a typo for processes, or this discussion is
getting rather silly ....

M.

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Received on Sun Nov 7 11:11:48 2004

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