On 1/17/24 10:36 AM, Bart Van Assche wrote: > On 1/16/24 15:34, Damien Le Moal wrote: >> FYI, I am about to post 20-something patches that completely remove zone write >> locking and replace it with "zone write plugging". That is done above the IO >> scheduler and also provides zone append emulation for drives that ask for it. >> >> With this change: >> - Zone append emulation is moved to the block layer, as a generic >> implementation. sd and dm zone append emulation code is removed. >> - Any scheduler can be used, including "none". mq-deadline zone block device >> special support is removed. >> - Overall, a lot less code (the series removes more code than it adds). >> - Reordering problems such as due to IO priority is resolved as well. >> >> This will need a lot of testing, which we are working on. But your help with >> testing on UFS devices will be appreciated as well. > > When posting this patch series, please include performance results > (IOPS) for a zoned null_blk device instance. mq-deadline doesn't support > more than 200 K IOPS, which is less than what UFS devices support. I > hope that this performance bottleneck will be solved with the new > approach. Not really zone related, but I was very aware of the single lock limitations when I ported deadline to blk-mq. Was always hoping that someone would actually take the time to make it more efficient, but so far that hasn't happened. Or maybe it'll be a case of "just do it yourself, Jens" at some point... -- Jens Axboe
