Re: kernel 2.6.13 buffer strangeness - ext2/3/reiser4/xfs comparison

[Anthony Wesley]

Andrew Morton wrote:

> Anthony Wesley <awesley@xxxxxxxxxxxxxxx> wrote:
>
> > I compared ext2,ext3,xfs,vfat,reiser and reiser4.
> >
> > The hands-down winner was ext2. All the others showed problems of either lower disk throughput
> > or dropped frames during video capture.
>
>
> ext2 is a good filesystem.  For that sort of application all the journaling
> gunk can really get in the way.
>
> You should have tested ext3 with data=writeback.

Ask and ye shall receive...

I created an ext3 fs, mounted it with data=writeback and gave it a quick spin.

The result? Lots of pauses and dropped frames during capture. This is during the part of the
process where I have gobs of free RAM that's being used for buffering so dropping frames here
is a cardinal sin.

Dunno why it's happening, but I saw it also with xfs and reiser4. ext2 on the other hand
chugs along happily, no pauses, no dropped frames until we run out of free RAM (takes about 2
minutes now after the simple kernel change).

I can understand dropped frames after we run out of ram, but not before.

regards, Anthony

--
Anthony Wesley
Director and IT/Network Consultant
Smart Networks Pty Ltd
Acquerra Pty Ltd

Anthony.Wesley@xxxxxxxxxxxxxxx
Phone: (02) 62595404 or 0419409836
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