Re: DBT-2 anticipatory scheduler and filesystem results with 2.6.1

[Nick Piggin]

Andrew Morton wrote:

> markw@xxxxxxxx wrote:
>
> > I ran some dbt-2 tests against 5 filesystems with 2.6.1-mm4 and 2.6.1. I
> > see a degradation from 0 to 7% in throughput. 
>
> -mm4 also had readahead changes which will adversely impact database-style
> workloads.  I'd suggest that you revert
>
> ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.1/2.6.1-mm4/broken-out/readahead-revert-lazy-readahead.patch
>
> and retest.
>
> We reverted lazy readahead because it broke NFS linear reads and was doing
> the wrong thing anyway.  We need to come up with something else for
> database-style workloads.

Oh good. I'd be a bit surprised if it were due to an as-iosched.c change 
that
caused the regression.

But there are changes in how new processes are handled, so if you have a lot
of io submitting processes being created, you might see a difference.


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