thrashing

[Glen Kaukola]

Hi there,

So for our newest simulations, we're working with a different domain, 
where each of our grid cells are much smaller, and so we're expecting 
the runs to take about 4 times longer.  But actually they're taking 
around 40 times longer.  I'm thinking this may have something to do with 
not having enough memory.  The problem with this theory is that I'm not 
really sure how to tell if my machines are thrashing.  On a desktop 
machine I can tell no problem, as the disk starts going crazy and the 
system pretty much grinds to a halt.  But on a machine up in my server 
room on which I don't have any gui and where it's too loud to hear any 
disk activity, I'm really not sure how to tell whether it's thrashing or 
not.  I mean, I can look at top, and free, and sar and everything 
doesn't look much different than when the other simulations were 
running, except for maybe 'sar -W', which is a little bit higher.  
Anyway, if someone could help me out with a way to determine without a 
doubt if my machines are thrashing or not, then I'd greatly appriciate it.

Thanks for your time,
Glen Kaukola

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