Re: graphical swap comparison of aa and rik vm

[safemode <safemode@speakeasy.net>]

On Thursday 01 November 2001 01:23, Mark Hahn wrote:
> > Here is the graph   http://safemode.homeip.net/vm_swapcomparison.png   .
> > It's
>
> here's my munge of the same data:
> 	http://mhahn.mcmaster.ca/~hahn/foo.png
> the measures I find interesting are the SI/SO rates.  first, the most
> obvious feature is that Rik-VM has a serious problem knowing when to *stop*
> swapping out.  but SO isn't a bad thing unless it's obsessive: it's when
> you see high *swap-in* that you know the VM has previously chosen bad pages
> to SO. and this is the second big difference: Rik-VM doesn't make nearly as
> many mistakes - especially look at Andrea-VM thrashing out-in-out at ~
> samples 26-32.
>
> also, if you merely sum the SI and SO columns for each:
> 		sum(SI)		sum(SO)		sum(SI+SO)
>       Rik-VM	43564		317448		290032
>       AA-VM	118284		171748		361012
> to me, this looks like the same point: Rik being SO-happy,
> Andrea having to SI a lot more.  interesting also that Andrea wins the
> race, in spite of poorer SO choices and more swap traffic overall.
>
> > Neadless to say that while running the test on either box, the entire
> > computer became unresponsive multiple times for extended lengths of
> > times.
>
> yes, unfortunately this corrupts the value of the data, since the
> timecourses are not really comparable, and samples are only vaguely related
> to time...

If you miss anything you miss the plateu data that would be found  when the 
IO peaks.  But i doubt much at all was really lost in this case.  
> regards, mark hahn.

Actually i found that most if not all of the vmstat's that weren't being 
displayed were displayed immediately after the "locks", ie. I got flooded 
with vmstats upon the computer becoming responsive again.   
Of course I should have been timing each run with a stopwatch, but that never 
crossed my mind that the vmstat would be lost.   In other words i thought of 
it as analogous to having burst-lag on irc.  Guess that's for tomorrow after 
work.