On 27 September 2017 at 00:25, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > On 22 September 2017 at 14:36, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote: >> Hi >> >> Here is V9 of the hardware command queue patches without the software >> command queue patches, now using blk-mq and now with blk-mq support for >> non-CQE I/O. >> >> HW CMDQ offers 25% - 50% better random multi-threaded I/O. I see a slight >> 2% drop in sequential read speed but no change to sequential write. >> >> Non-CQE blk-mq showed a 3% decrease in sequential read performance. This >> seemed to be coming from the inferior latency of running work items compared >> with a dedicated thread. Hacking blk-mq workqueue to be unbound reduced the >> performance degradation from 3% to 1%. >> >> While we should look at changing blk-mq to give better workqueue performance, >> a bigger gain is likely to be made by adding a new host API to enable the >> next already-prepared request to be issued directly from within ->done() >> callback of the current request. > > I have looked at patch 1->8, and those looks nice to me so I have > applied those for next. I will do my best to review the rest asap, > however I am currently traveling so in worst case it will have wait > until next week. Adrian, I decided to drop patch6, the one which adds the Kconfig option for blkmq for now. Please re-post it when you get to the point of sending a version of the series. Kind regards Uffe
