Re: [PATCH] (2/2) reverse mappings for current 2.5.23 VM

Daniel Phillips
2002-06-19T17:01:23Z

On Wednesday 19 June 2002 13:58, Rik van Riel wrote:
> > 2.5.22 vanilla:
> > Total kernel swapouts during test = 29068 kB
> > Total kernel swapins during test = 16480 kB
> > Elapsed time for test: 141 seconds
> >
> > 2.5.23-rmap (this patch -- "rmap-minimal"):
> > Total kernel swapouts during test = 24068 kB
> > Total kernel swapins during test = 6480 kB
> > Elapsed time for test: 133 seconds
> >
> > 2.5.23-rmap13b (Rik's "rmap-13b complete") :
> > Total kernel swapouts during test = 40696 kB
> > Total kernel swapins during test = 380 kB
> > Elapsed time for test: 133 seconds
>
> Interesting to see that both rmap versions have the same
> performance, it would seem that swapouts are much cheaper
> than waiting for a pagefault to swap something in ...

You might conclude from the above that the lru+rmap is superior to
aging+rmap: while they show the same wall-clock time, lru+rmap consumes
considerably less disk bandwidth. Naturally, it would be premature to
conclude this from one trial on one load.

These patches need benchmarking - lots of it, and preferrably in the next few
days.

We need to see cpu stats as well.

--
Daniel