Messages in this thread | | | Date | Sat, 27 Nov 2010 19:50:28 +0100 | From | Jens Axboe <> | Subject | Re: [PATCHSET] backing-dev: replace private thread pool with workqueue |
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On 2010-11-27 17:02, Tejun Heo wrote: > On 09/07/2010 02:36 PM, Tejun Heo wrote: >> Hello, >> >> On 09/07/2010 02:29 PM, Jens Axboe wrote: >>> I agree (with both of you). It's definitely too early to convert it >>> over, but if we can in the longer run, it never hurts to get rid of >>> code. The writeback threads aren't a typical threadpool, in that the >>> threads stick around and only go away when idle for too long. If they >>> stick around, you get the same process hammering IO at your device. So >>> converting that over to the generic cwq may or may not be at a >>> performance cost, it'll definitely have to be tested. >> >> One thing to try is removing WQ_UNBOUND and see how it affects the >> performance. I put WQ_UNBOUND there mainly to keep the behavior about >> the same as the current code but given what it does I think it would >> probably fare better with workers bound to CPUs. > > cmwq now seems pretty solid. There hasn't been any noticeable failure > yet. I think we can move on with this conversion now. Shall I > refresh the patchset against the current block tree?
I'd still prefer to wait a while. The writeback code is still very much a moving target, so I don't think mixing in a different work queue scheme is likely going to do anyone any good at this point in time.
-- Jens Axboe
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