On 06/27/14 00:07, Elliott, Robert (Server Storage) wrote: >> -----Original Message----- >> From: Jens Axboe [mailto:axboe@xxxxxxxxx] >> Sent: Wednesday, 25 June, 2014 11:51 PM >> To: Christoph Hellwig; James Bottomley >> Cc: Bart Van Assche; Elliott, Robert (Server Storage); linux- >> scsi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx >> Subject: Re: scsi-mq V2 >> >> On 2014-06-25 10:51, Christoph Hellwig wrote: >>> This is the second post of the scsi-mq series. >>> > ... >>> >>> Changes from V1: >>> - rebased on top of the core-for-3.17 branch, most notable the >>> scsi logging changes >>> - fixed handling of cmd_list to prevent crashes for some heavy >>> workloads >>> - fixed incorrect handling of !target->can_queue >>> - avoid scheduling a workqueue on I/O completions when no queues >>> are congested >>> >>> In addition to the patches in this thread there also is a git available at: >>> >>> git://git.infradead.org/users/hch/scsi.git scsi-mq.2 >> >> You can add my acked/reviewed-by to the series. > > Since March 20th (circa LSF-MM 2014) we've run many hours of tests > with hpsa and the scsi-mq tree. We've also done a little bit of > testing with mpt3sas and, in the last few days, scsi_debug. > > Although there are certainly more problems to find and improvements > to be made, it's become quite stable. It's even been used on the > boot drives of our test servers. > > For the patches in scsi-mq.2 you may add: > Tested-by: Robert Elliott <elliott@xxxxxx> Performance of scsi-mq-v2 looks even better than that of scsi-mq-v1. The slight single-LUN regression is gone, peak IOPS with use_blk_mq=Y on my test setup is now 3x the performance of use_blk_mq=N and latency has been reduced further. I think this means reducing the number of context switches did really help :-) Detailed measurement results can be found on https://drive.google.com/file/d/0B1YQOreL3_FxWmZfbl8xSzRfdGM/. If you want you may add to the scsi-mq-v2 patch series: Tested-by: Bart Van Assche <bvanassche@xxxxxxx> Bart. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
