On Mon, Jan 29, 2018 at 12:56:30PM -0800, James Bottomley wrote: > On Mon, 2018-01-29 at 23:46 +0800, Ming Lei wrote: > [...] > > 2. When to enable SCSI_MQ at default again? > > I'm not sure there's much to discuss ... I think the basic answer is as > soon as Christoph wants to try it again.
I guess Christoph still need to evaluate if there are existed issues or blockers before trying it again. And more input may be got from F2F discussion, IMHO. > > > SCSI_MQ is enabled on V3.17 firstly, but disabled at default. In > > V4.13-rc1, it is enabled at default, but later the patch is reverted > > in V4.13-rc7, and becomes disabled at default too. > > > > Now both the original reported PM issue(actually SCSI quiesce) and > > the sequential IO performance issue have been addressed. > > Is the blocker bug just not closed because no-one thought to do it: > > https://bugzilla.kernel.org/show_bug.cgi?id=178381 > > (we have confirmed that this issue is now fixed with the original > reporter?) >From a developer view, this issue is fixed by the following commit: 3a0a52997(block, scsi: Make SCSI quiesce and resume work reliably), and it is verified by kernel list reporter. > > And did the Huawei guy (Jonathan Cameron) confirm his performance issue > was fixed (I don't think I saw email that he did)? Last time I talked with John Garry about the issue, and the merged .get_budget based patch improves much on the IO performance, but there is still a bit gap compared with legacy path. Seems a driver specific issue, remembered that removing a driver's lock can improve performance much. Garry, could you provide further update on this issue? Thanks, Ming
