Re: ext3 IO latency measurements (was: Linux 2.6.29)

Andrew Morton
2009-03-26T23:06:35Z

On Thu, 26 Mar 2009 15:39:53 -0700 (PDT) Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Thu, 26 Mar 2009, Jan Kara wrote:
> >
> > Reads are measurably better with the patch - the test with cat you
> > describe below took ~0.5s per file without the patch and always less than
> > 0.02s with the patch. So it seems to help something.
>
> That would seem to be a _huge_ improvement.

It's strange that we still don't have an ext3_writepages(). Open a
transaction, do a large pile of writes, close the transaction again.
We don't even have a data=writeback writepages() implementation, which
should be fairly simple.

Bizarre.

Mingming had a shot at it a few years ago and I think Badari did as
well, but I guess it didn't work out.

Falling back to generic_writepages() on our main local fs is a bit lame.