Re: Linux 2.6.29

Ingo Molnar
2009-04-02T01:01:18Z

* Andrew Morton <akpm@linux-foundation.org> wrote:

> On Wed, 1 Apr 2009 17:03:38 -0400
> lsorense@csclub.uwaterloo.ca (Lennart Sorensen) wrote:
>
> > On Thu, Mar 26, 2009 at 06:25:19PM -0700, Andrew Morton wrote:
> > > The JBD journal is a massive designed-in contention point. It's why
> > > for several years I've been telling anyone who will listen that we need
> > > a new fs. Hopefully our response to all these problems will soon be
> > > "did you try btrfs?".
> >
> > Oh I look forward to the day when it will be safe to convert my mythtv
> > box from ext3 to btrfs. Current kernels just have too much IO latency
> > with ext3 it seems. Older kernels were more responsive, but probably
> > had other places they were less efficient.
>
> Back in 2002ish I did a *lot* of work on IO latency,
> reads-vs-writes, etc, etc (but not fsync - for practical purposes
> it's unfixable on ext3-ordered)
>
> Performance was pretty good. From some of the descriptions I'm
> seeing get tossed around lately, I suspect that it has regressed.
>
> It would be useful/interesting if people were to rerun some of these
> tests with `echo anticipatory > /sys/block/sda/queue/scheduler'.

I'll test this (and the other suggestions) once i'm out of the merge
window.

> Or with linux-2.5.60 :(

I probably wont test that though ;-)

Going back to v2.6.14 to do pre-mutex-merge performance tests was
already quite a challenge on modern hardware.

Ingo