On 09/18/2019 12:49 PM, Jens Axboe wrote: > What is this new request type that supports merging? > > My point is that adding stats like this isn't free, it's a runtime cost. > And if it's just for debugging, there better be a damn good reason for > why we'd want to pay this cost the 99.999% of the time where nobody is > looking at those counters. > > So why isn't the iostat stuff good enough? There's also the option of > having blktrace tell you this information, it would not be hard to add a > blktrace-stats type of tool that'll just give you the last second of > stats so you wouldn't have to store the data, for example. > > What I'm asking for is justification for adding these stats, so far I > don't see any outside of perhaps convenience, it's easier to just add > them to blk-mq and retrieve them through debugfs. Thanks for the explanation, make sense to drop these patches and rely on other tools.
