On Tue, Jan 31, 2012 at 09:52:10PM +0000, Brian Candler wrote:

On Tue, Jan 31, 2012 at 09:52:05AM -0500, Christoph Hellwig wrote:

quoted

You don't just read a single file at a time but multiple ones, don't
you?

It's sequential at the moment, although I'll do further tests with the -c
(concurrency) option to bonnie++

quoted

Try playing with the following tweaks to get larger I/O to the disk:

 a) make sure you use the noop or deadline elevators
 b) increase /sys/block/sdX/queue/max_sectors_kb from its low default
 c) dramatically increase /sys/devices/virtual/bdi/<major>:<minor>/read_ahead_kb

Thank you very much: I will do further tests with these.

Is the read_ahead_kb knob aware of file boundaries? That is, is there any
risk that if I set it too large it would read useless blocks past the end of
the file?

Yes, readahead only occurs within the file, and won't readahead past
EOF.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs