On Fri, Oct 11, 2019 at 4:54 PM John Garry <john.garry@xxxxxxxxxx> wrote: > > On 10/10/2019 12:21, John Garry wrote: > > > >> > >> As discussed before, tags of hisilicon V3 is HBA wide. If you switch > >> to real hw queue, each hw queue has to own its independent tags. > >> However, that isn't supported by V3 hardware. > > > > I am generating the tag internally in the driver now, so that hostwide > > tags issue should not be an issue. > > > > And, to be clear, I am not paying too much attention to performance, but > > rather just hotplugging while running IO. > > > > An update on testing: > > I did some scripted overnight testing. The script essentially loops like > > this: > > - online all CPUS > > - run fio binded on a limited bunch of CPUs to cover a hctx mask for 1 > > minute > > - offline those CPUs > > - wait 1 minute (> SCSI or NVMe timeout) > > - and repeat > > > > SCSI is actually quite stable, but NVMe isn't. For NVMe I am finding > > some fio processes never dying with IOPS @ 0. I don't see any NVMe > > timeout reported. Did you do any NVMe testing of this sort? > > > > Yeah, so for NVMe, I see some sort of regression, like this: > Jobs: 1 (f=1): [_R] [0.0% done] [0KB/0KB/0KB /s] [0/0/0 iops] [eta > 1158037877d:17h:18m:22s] I can reproduce this issue, and looks there are requests in ->dispatch. I am a bit busy this week, please feel free to investigate it and debugfs can help you much. I may have time next week for looking this issue. Thanks, Ming Lei
