Messages in this thread | | | Date | Wed, 20 Nov 2013 09:20:13 -0700 | From | Jens Axboe <> | Subject | Re: [Regression x2, 3.13-git] virtio block mq hang, iostat busted on virtio devices |
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On 11/20/2013 01:04 AM, Christoph Hellwig wrote: > On Tue, Nov 19, 2013 at 02:43:51PM -0700, Jens Axboe wrote: >> No, the nr_requests isn't actually relevant in the blk-mq context, the >> driver sets its own depth. For the above, it's 64 normal commands, and 2 >> reserved. The reserved would be for a flush, for instance. If someone >> attempts to queue more than the allocated number of requests, it'll stop >> the blk-mq queue and kick things into gear on the virtio side. Then when >> requests complete, we start the queue again. > > Btw, any reason we lowerered the queue depth from 128 to 64 in > virtio-blk?
No, we can easily bump it to 128 again, I think it was a leftover from where it had more queues and testing.
-- Jens Axboe
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