On Wed, Apr 22, 2020 at 07:41:30AM -0700, James Bottomley wrote: > On Wed, 2020-04-22 at 17:54 +0800, Ming Lei wrote: > > The following three fields of scsi_host_template are referenced in > > scsi IO submission path, so put them together into one cacheline: > > > > - cmd_size > > - queuecommand > > - commit_rqs > > Are there benchmarks to show this actually makes a difference, if so, > how much? Originally I observed 40% IOPS boost on scsi_debug by moving the three fields into scsi_host, but I lost that test environment now. When I run fio on scsi_debug in another machine, IOPS gets ~10% boost with this patch. Thanks, Ming