Re: [PATCH] token based thrashing control

From: Con Kolivas
Date: Mon Aug 02 2004 - 00:20:54 EST


Con Kolivas wrote:
Rik van Riel wrote:

On Mon, 2 Aug 2004, Con Kolivas wrote:


We have some results that need interpreting with contest.
mem_load:
Kernel [runs] Time CPU% Loads LCPU% Ratio
2.6.8-rc2 4 78 146.2 94.5 4.7 1.30
2.6.8-rc2t 4 318 40.9 95.2 1.3 5.13

The "load" with mem_load is basically trying to allocate 110% of free ram, so the number of "loads" although similar is not a true indication of how much ram was handed out to mem_load. What is interesting is that since mem_load runs continuously and constantly asks for too much ram it seems to be receiving the token most frequently in preference to the cc processes which are short lived. I'd say it is quite hard to say convincingly that this is bad because the point of this patch is to prevent swap thrash.



It may be worth trying with a shorter token timeout
time - maybe even keeping the long ineligibility ?


Give them a "refractory" bit which is set if they take the token? Next time they try to take the token unset the refractory bit instead of taking the token.

Or take that concept even further; Give them an absolute refractory period where they cannot take the token again and a relative refractory bit which can only be reset after the refractory period is over.

Con

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