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. Without patch - 4.64% [megaraid_sas] [k] complete_cmd_fusion 3.23% [kernel] [k] irq_entries_start 3.18% [kernel] [k] _raw_spin_lock 3.06% [kernel] [k] syscall_return_via_sysret 2.74% [kernel] [k] bt_iter 2.55% [kernel] [k] scsi_queue_rq 2.21% [megaraid_sas] [k] megasas_build_io_fusion 1.80% [megaraid_sas] [k] megasas_queue_command 1.59% [kernel] [k] __audit_syscall_exit 1.55% [kernel] [k] _raw_spin_lock_irqsave 1.38% [megaraid_sas] [k] megasas_build_and_issue_cmd_fusion 1.34% [kernel] [k] do_io_submit 1.33% [kernel] [k] gup_pgd_range 1.26% [kernel] [k] scsi_softirq_done 1.20% fio [.] __fio_gettime 1.20% [kernel] [k] switch_mm_irqs_off 1.00% [megaraid_sas] [k] megasas_build_ldio_fusion 0.97% fio [.] get_io_u 0.89% [kernel] [k] lookup_ioctx 0.80% [kernel] [k] scsi_dec_host_busy 0.78% [kernel] [k] blkdev_direct_IO 0.78% [megaraid_sas] [k] MR_GetPhyParams 0.73% [kernel] [k] aio_read_events 0.70% [megaraid_sas] [k] MR_BuildRaidContext 0.64% [kernel] [k] blk_mq_complete_request 0.64% fio [.] thread_main 0.63% [kernel] [k] blk_queue_split 0.63% [kernel] [k] blk_mq_get_request 0.61% [kernel] [k] read_tsc 0.59% [kernel] [k] kmem_cache_a With patch - 4.36% [megaraid_sas] [k] complete_cmd_fusion 3.24% [kernel] [k] irq_entries_start 3.00% [kernel] [k] syscall_return_via_sysret 2.41% [kernel] [k] scsi_queue_rq 2.41% [kernel] [k] _raw_spin_lock 2.22% [megaraid_sas] [k] megasas_build_io_fusion 1.92% [kernel] [k] bt_iter 1.74% [megaraid_sas] [k] megasas_queue_command 1.48% [kernel] [k] gup_pgd_range 1.44% [kernel] [k] __audit_syscall_exit 1.33% [megaraid_sas] [k] megasas_build_and_issue_cmd_fusion 1.29% [kernel] [k] _raw_spin_lock_irqsave 1.25% fio [.] get_io_u 1.24% fio [.] __fio_gettime 1.22% [kernel] [k] do_io_submit 1.18% [megaraid_sas] [k] megasas_build_ldio_fusion 1.02% [kernel] [k] blk_mq_get_request 0.91% [kernel] [k] lookup_ioctx 0.91% [kernel] [k] scsi_softirq_done 0.88% [kernel] [k] scsi_dec_host_busy 0.87% [kernel] [k] blkdev_direct_IO 0.77% [megaraid_sas] [k] MR_BuildRaidContext 0.76% [megaraid_sas] [k] MR_GetPhyParams 0.73% [kernel] [k] __fget 0.70% [kernel] [k] switch_mm_irqs_off 0.70% fio [.] thread_main 0.69% [kernel] [k] aio_read_events 0.68% [kernel] [k] note_interrupt 0.65% [kernel] [k] do_syscal Kashyap > -----Original Message----- > From: Ming Lei [mailto:ming....@redhat.com] > Sent: Tuesday, February 27, 2018 3:38 PM > To: Jens Axboe; linux-bl...@vger.kernel.org; Christoph Hellwig; Mike Snitzer > Cc: linux-scsi@vger.kernel.org; Hannes Reinecke; Arun Easi; Omar Sandoval; > Martin K . Petersen; James Bottomley; Christoph Hellwig; Don Brace; Kashyap > Desai; Peter Rivera; Laurence Oberman; Ming Lei > Subject: [PATCH V3 8/8] scsi: megaraid: improve scsi_mq performance via > .host_tagset > > It is observed on null_blk that IOPS can be improved much by simply making > hw queue per NUMA node, so this patch applies the introduced .host_tagset > for improving performance. > > In reality, .can_queue is quite big, and NUMA node number is often small, so > each hw queue's depth should be high enough to saturate device. > > Cc: Arun Easi <arun.e...@cavium.com> > Cc: Omar Sandoval <osan...@fb.com>, > Cc: "Martin K. Petersen" <martin.peter...@oracle.com>, > Cc: James Bottomley <james.bottom...@hansenpartnership.com>, > Cc: Christoph Hellwig <h...@lst.de>, > Cc: Don Brace <don.br...@microsemi.com> > Cc: Kashyap Desai <kashyap.de...@broadcom.com> > Cc: Peter Rivera <peter.riv...@broadcom.com> > Cc: Laurence Oberman <lober...@redhat.com> > Cc: Hannes Reinecke <h...@suse.de> > Cc: Mike Snitzer <snit...@redhat.com> > Signed-off-by: Ming Lei <ming....@redhat.com> > --- > drivers/scsi/megaraid/megaraid_sas_base.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c > b/drivers/scsi/megaraid/megaraid_sas_base.c > index 065956cb2aeb..0b46f97cbfdb 100644 > --- a/drivers/scsi/megaraid/megaraid_sas_base.c > +++ b/drivers/scsi/megaraid/megaraid_sas_base.c > @@ -3177,6 +3177,7 @@ static struct scsi_host_template megasas_template > = { > .use_clustering = ENABLE_CLUSTERING, > .change_queue_depth = scsi_change_queue_depth, > .no_write_same = 1, > + .host_tagset = 1, > }; > > /** > @@ -5947,6 +5948,8 @@ static int megasas_start_aen(struct > megasas_instance *instance) static int megasas_io_attach(struct > megasas_instance *instance) { > struct Scsi_Host *host = instance->host; > + /* 256 tags should be high enough to saturate device */ > + int max_queues = DIV_ROUND_UP(host->can_queue, 256); > > /* > * Export parameters required by SCSI mid-layer @@ -5987,6 +5990,9 > @@ static int megasas_io_attach(struct megasas_instance *instance) > host->max_lun = MEGASAS_MAX_LUN; > host->max_cmd_len = 16; > > + /* per NUMA node hw queue */ > + host->nr_hw_queues = min_t(int, nr_node_ids, max_queues); > + > /* > * Notify the mid-layer about the new controller > */ > -- > 2.9.5
