[dm-devel] Re: Ext3 sequential read performance drop 2.6.29 -> 2.6.30,2.6.31,...

[Christoph Hellwig]

On Mon, Nov 02, 2009 at 01:55:54PM -0800, Andrew Morton wrote:
> On Tue, 13 Oct 2009 12:09:55 +0200
> Laurent CORBES <laurent.corbes at smartjog.com> wrote:
> 
> > Hi all,
> > 
> > While benchmarking some systems I discover a big sequential read performance
> > drop using ext3 on ~ big files. The drop seems to be introduced in 2.6.30. I'm
> > testing with 2.6.28.6 -> 2.6.29.6 -> 2.6.30.4 -> 2.6.31.3.
> 
> Seems that large performance regressions aren't of interest to this
> list :(

No sure which list you mean, but dm-devel is for dm, not md.  We're also
seeing similarly massive performance drops with md and ext3/xfs as
already reported on the list.  Someone tracked it down to writeback
changes as usual, but there it got stuck.