Re: [PATCH 6/9] clockpro-clockpro.patch

Marcelo Tosatti
2006-01-03T14:22:04Z

On Sun, Jan 01, 2006 at 11:37:34AM +0100, Peter Zijlstra wrote:
> On Sat, 2005-12-31 at 20:40 -0200, Marcelo Tosatti wrote:
> > On Fri, Dec 30, 2005 at 11:43:34PM +0100, Peter Zijlstra wrote:
> > >
> > > From: Peter Zijlstra <a.p.zijlstra@chello.nl>
> >
> > Peter,
> >
> > I tried your "scan-shared.c" proggy which loops over 140M of a file
> > using mmap (on a 128MB box). The number of loops was configured to "5".
> >
> > The amount of major/minor pagefaults was exactly the same between
> > vanilla and clockpro, isnt the clockpro algorithm supposed to be
> > superior than LRU in such "sequential scan of MEMSIZE+1" cases?
>
> yes it should, hmm, have to look at that then.
>
> What should happen is that nr_cold_target should drop to the bare
> minimum, which effectivly pins all hot pages and only rotates the few
> cold pages.

I screwed up the tests. Here are the real numbers.

Test: scan 140MB file sequentially, 5 times.
Env: 128Mb machine

CLOCK-Pro: 0:49:98elapsed 18%CPU
7358maj+95308min

vanilla:
1:28.05elapsed 11%CPU
12950maj+166374min

Kicking some large arses!