Re: Review: Concurrent Multi-File Data Streams

Andi Kleen
2007-05-12T17:49:24Z

David Chinner <dgc@sgi.com> writes:
>
> The following patch survives XFSQA with timeouts set to minimum,
> default, 500s and maximum. The patch has not had a great
> deal of low memory testing, and the object cache may need a shrinker
> interface to work in low memory conditions.
>
> Comments?

It seems to be an optimization for a relatively small number of streams. When you
do a large number on average you should get similar readahead benefits
from round robing the streams over some AGs vs keeping it in a single AG,
right?

The fallback to AG 0 if nstreams>AGs seems pretty lousy. Wouldn't it be better
to do the normal XFS allocation algorithm then? I think right now it will
go into low space mode in this case, which might give worse results.

Also centisecs is a really ugly unit whose use should be probably not propagated.

-Andi