From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Subject: Re: [dm-devel] dm-multipath test scripts Date: Sat, 20 Feb 2016 07:13:07 -0800 Message-ID: <56C88283.3050704@sandisk.com> References: <20151007053923.GA10749@xzibit.linux.bs1.fc.nec.co.jp> <20160218171745.GA15071@redhat.com> <56C662F1.8070407@ce.jp.nec.com> <56C6D45A.6060407@ce.jp.nec.com> <20160219194216.GB21133@redhat.com> <20160220061247.GA23333@redhat.com> <56C834F8.8050604@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <56C834F8.8050604@suse.de> Sender: linux-scsi-owner@vger.kernel.org To: Hannes Reinecke , Mike Snitzer , Junichi Nomura Cc: device-mapper development , linux-scsi List-Id: dm-devel.ids On 02/20/16 01:42, Hannes Reinecke wrote: > ATM the only SCSI driver to support SCSI-mq properly are lpfc, virtio, > and fnic. None of the other driver have been modified, and I suspect the > performance might be less than stellar. Hello Hannes, Before scsi-mq support was added to the above drivers it was added to the ib_srp driver. Apparently today there are multiple drivers that support multiple hardware queues: $ git grep -nH 'nr_hw_queues = [^1]' | grep -vE 'block/blk-mq|scsi/scsi_lib' drivers/block/null_blk.c:667: nullb->tag_set.nr_hw_queues = submit_queues; drivers/block/virtio_blk.c:638: vblk->tag_set.nr_hw_queues = vblk->num_vqs; drivers/block/xen-blkfront.c:927: info->tag_set.nr_hw_queues = info->nr_rings; drivers/infiniband/ulp/srp/ib_srp.c:3337: target->scsi_host->nr_hw_queues = target->ch_count; drivers/nvme/host/pci.c:1680: dev->tagset.nr_hw_queues = dev->online_queues - 1; drivers/scsi/lpfc/lpfc_init.c:3318: shost->nr_hw_queues = phba->cfg_fcp_io_channel; drivers/scsi/virtio_scsi.c:1008: shost->nr_hw_queues = num_queues; Performance data is available in http://events.linuxfoundation.org/sites/events/files/slides/Vault%20-%20scsi-mq%20v2.pdf. Bart.