Messages in this thread | | | Date | Tue, 23 Jun 2009 12:56:46 +0200 | From | Jens Axboe <> | Subject | Re: merging the per-bdi writeback patchset |
| |
On Tue, Jun 23 2009, KOSAKI Motohiro wrote: > Hi > > > On Tue, Jun 23 2009, Andrew Morton wrote: > > > On Tue, 23 Jun 2009 10:11:56 +0200 Jens Axboe <jens.axboe@oracle.com> wrote: > > > > > > > Things are looking good for this patchset and it's been in -next for > > > > almost a week without any reports of problems. So I'd like to merge it > > > > for 2.6.31 if at all possible. Any objections? > > > > > > erk. I was rather expecting I'd have time to have a look at it all. > > > > OK, we can wait if we have to, just trying to avoid having to keep this > > fresh for one full cycle. I have posted this patchset 11 times though > > over months, so it's not like it's a new piece of work :-) > > > > > It's unclear to me actually _why_ the performance changes which were > > > observed have actually occurred. In fact it's a bit unclear (to me) > > > why the patchset was written and what it sets out to achieve :( > > > > It started out trying to get rid of the pdflush uneven writeout. If you > > look at various pdflush intensive workloads, even on a single disk you > > often have 5 or more pdflush threads working the same device. It's just > > not optimal. Another issue was starvation with request allocation. Given > > that pdflush does non-blocking writes (it has to, by design), pdflush > > can potentially be starved if someone else is working the device. > > Can you please make reproduce program and post mesurement result? > I hope to mesure the same program on my box.
For which issue? Lumpy writeout can often be observed just by doing buffered writes to a bunch of files.
> Plus, Can you please write more vervose patch description? your patch is a > bit harder review.
OK, I can probably improve on that. Do you mean the general description of the patchset, or some of the individual patches?
-- Jens Axboe
| |