Re: 2.6.1 slower than 2.4, smp/scsi/sw-raid/reiserfs

[Nick Piggin]

Philip Martin wrote:

> Andrew Morton <akpm@xxxxxxxx> writes:
>
>
> > Nick Piggin <piggin@xxxxxxxxxxxxxxx> wrote:
> >
> > > Andrew, any other ideas?
> > There seems to be a lot more writeout happening.
>
> As far as I can see (and hear!) that's true.
>
>
> > You could try setting /proc/sys/vm/dirty_ratio to 60 and
> > /proc/sys/vm/dirty_background_ratio to 40.
>
> Not much different:
>
> 2.6.1 (without elevator=deadline)
>
> dirty_ratio:60 dirty_background_ratio:40
>
> 245.58user 121.82system 3:31.79elapsed 173%CPU (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (0major+3771340minor)pagefaults 0swaps
>
> dirty_ratio:40 dirty_background_ratio:10  (the defaults)
>
> 245.75user 121.33system 3:35.13elapsed 170%CPU (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (0major+3770826minor)pagefaults 0swaps

OK now thats strange - you're definitely compiling the same kernel
with the same .config and compiler? 2.6 looks like its doing twice
the amount of writeout that 2.4 is.

Can you try the memory pressure program I sent you earlier?

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