On Wed, Feb 28, 2018 at 08:28:48PM +0530, Kashyap Desai wrote: > Ming - > > Quick testing on my setup - Performance slightly degraded (4-5% drop)for > megaraid_sas driver with this patch. (From 1610K IOPS it goes to 1544K) > I confirm that after applying this patch, we have #queue = #numa node. > > ls -l > /sys/devices/pci0000:80/0000:80:02.0/0000:83:00.0/host10/target10:2:23/10: > 2:23:0/block/sdy/mq > total 0 > drwxr-xr-x. 18 root root 0 Feb 28 09:53 0 > drwxr-xr-x. 18 root root 0 Feb 28 09:53 1 > > > I would suggest to skip megaraid_sas driver changes using shared_tagset > until and unless there is obvious gain. If overall interface of using > shared_tagset is commit in kernel tree, we will investigate (megaraid_sas > driver) in future about real benefit of using it.
Hi Kashyap, Now I have put patches for removing operating on scsi_host->host_busy in V4, especially which are done in the following 3 patches: 9221638b9bc9 scsi: avoid to hold host_busy for scsi_mq 1ffc8c0ffbe4 scsi: read host_busy via scsi_host_busy() e453d3983243 scsi: introduce scsi_host_busy() Could you run your test on V4 and see if IOPS can be improved on megaraid_sas?  https://github.com/ming1/linux/commits/v4.16-rc-host-tags-v4 Thanks, Ming