Re: [MMTests] dbench4 async on ext3

[Jan Kara]

On Mon 23-07-12 22:21:46, Mel Gorman wrote:
> Configuration:	global-dhp__io-dbench4-async-ext3
> Result: 	http://www.csn.ul.ie/~mel/postings/mmtests-20120424/global-dhp__io-dbench4-async-ext3
> Benchmarks:	dbench4
> 
> Summary
> =======
> 
> In general there was a massive drop in throughput after 3.0. Very broadly
> speaking it looks like the Read operation got faster but at the cost of
> a big regression in the Flush operation.
  Mel, I had a look into this and it's actually very likely only a
configuration issue. In 3.1 ext3 started to default to enabled barriers
(barrier=1 in mount options) which is a safer but slower choice. When I set
barriers explicitely, I see no performance difference for dbench4 between
3.0 and 3.1.

								Honza
-- 
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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