On Tue, Oct 16, 2018 at 08:26:31AM -0600, Jens Axboe wrote: > > Yes. Shall I send a patch with your suggestion or will you? > > Christoph should just fold it in, the bug only exists after his > change to it. Sorry, I missed what suggestion we had. Is that the patch form Jens earlier? > > > I have one more question, in your first conversion you set queue_depth to 2. > > How does one know this value? > > My conversion has 64, which is more or less an educated guess... ;) > > 64 is most likely just fine. Some drivers rely on having 1 in flight and > it's easier to manage to just let blk-mq take care of that. Outside of that, > there aren't any magic values. We should probably just use BLKDEV_MAX_RQ > for ones that don't have a specific hw limit or need. Is a queue depth > 1 actually safe for ubd? There are some odd global variables tracking struct io_thread_req.
