From mboxrd@z Thu Jan 1 00:00:00 1970 From: snitzer@redhat.com (Mike Snitzer) Date: Wed, 27 Jan 2016 13:42:46 -0500 Subject: dm-multipath low performance with blk-mq In-Reply-To: <56A904B6.50407@dev.mellanox.co.il> References: <569E11EA.8000305@dev.mellanox.co.il> <20160119224512.GA10515@redhat.com> <20160125214016.GA10060@redhat.com> <20160125233717.GQ24960@octiron.msp.redhat.com> <20160126132939.GA23967@redhat.com> <56A8A6A8.9090003@dev.mellanox.co.il> <20160127174828.GA31802@redhat.com> <56A904B6.50407@dev.mellanox.co.il> Message-ID: <20160127184245.GC31802@redhat.com> On Wed, Jan 27 2016 at 12:56pm -0500, Sagi Grimberg wrote: > > > On 27/01/2016 19:48, Mike Snitzer wrote: > > > >BTW, I _cannot_ get null_blk to come even close to your reported 1500K+ > >IOPs on 2 "fast" systems I have access to. Which arguments are you > >loading the null_blk module with? > > > >I've been using: > >modprobe null_blk gb=4 bs=4096 nr_devices=1 queue_mode=2 submit_queues=12 > > $ for f in /sys/module/null_blk/parameters/*; do echo $f; cat $f; done > /sys/module/null_blk/parameters/bs > 512 > /sys/module/null_blk/parameters/completion_nsec > 10000 > /sys/module/null_blk/parameters/gb > 250 > /sys/module/null_blk/parameters/home_node > -1 > /sys/module/null_blk/parameters/hw_queue_depth > 64 > /sys/module/null_blk/parameters/irqmode > 1 > /sys/module/null_blk/parameters/nr_devices > 2 > /sys/module/null_blk/parameters/queue_mode > 2 > /sys/module/null_blk/parameters/submit_queues > 24 > /sys/module/null_blk/parameters/use_lightnvm > N > /sys/module/null_blk/parameters/use_per_node_hctx > N > > $ fio --group_reporting --rw=randread --bs=4k --numjobs=24 > --iodepth=32 --runtime=99999999 --time_based --loops=1 > --ioengine=libaio --direct=1 --invalidate=1 --randrepeat=1 > --norandommap --exitall --name task_nullb0 --filename=/dev/nullb0 > task_nullb0: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, > ioengine=libaio, iodepth=32 > ... > fio-2.1.10 > Starting 24 processes > Jobs: 24 (f=24): [rrrrrrrrrrrrrrrrrrrrrrrr] [0.0% done] > [7234MB/0KB/0KB /s] [1852K/0/0 iops] [eta 1157d:09h:46m:22s] Thanks, the number of fio threads was pretty important. I'm still seeing better IOPs with queue_mode=0 (bio-based). Jobs: 24 (f=24): [r(24)] [11.7% done] [11073MB/0KB/0KB /s] [2835K/0/0 iops] [eta 14m:42s] (with queue_mode=2 I get ~1930K IOPs.. which I need to use to stack request-based DM multipath ontop) Now I can focus on why dm-multipath is slow... From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: dm-multipath low performance with blk-mq Date: Wed, 27 Jan 2016 13:42:46 -0500 Message-ID: <20160127184245.GC31802@redhat.com> References: <569E11EA.8000305@dev.mellanox.co.il> <20160119224512.GA10515@redhat.com> <20160125214016.GA10060@redhat.com> <20160125233717.GQ24960@octiron.msp.redhat.com> <20160126132939.GA23967@redhat.com> <56A8A6A8.9090003@dev.mellanox.co.il> <20160127174828.GA31802@redhat.com> <56A904B6.50407@dev.mellanox.co.il> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <56A904B6.50407@dev.mellanox.co.il> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Sagi Grimberg Cc: axboe@kernel.dk, Christoph Hellwig , "linux-nvme@lists.infradead.org" , "keith.busch@intel.com" , device-mapper development , Bart Van Assche List-Id: dm-devel.ids On Wed, Jan 27 2016 at 12:56pm -0500, Sagi Grimberg wrote: > > > On 27/01/2016 19:48, Mike Snitzer wrote: > > > >BTW, I _cannot_ get null_blk to come even close to your reported 1500K+ > >IOPs on 2 "fast" systems I have access to. Which arguments are you > >loading the null_blk module with? > > > >I've been using: > >modprobe null_blk gb=4 bs=4096 nr_devices=1 queue_mode=2 submit_queues=12 > > $ for f in /sys/module/null_blk/parameters/*; do echo $f; cat $f; done > /sys/module/null_blk/parameters/bs > 512 > /sys/module/null_blk/parameters/completion_nsec > 10000 > /sys/module/null_blk/parameters/gb > 250 > /sys/module/null_blk/parameters/home_node > -1 > /sys/module/null_blk/parameters/hw_queue_depth > 64 > /sys/module/null_blk/parameters/irqmode > 1 > /sys/module/null_blk/parameters/nr_devices > 2 > /sys/module/null_blk/parameters/queue_mode > 2 > /sys/module/null_blk/parameters/submit_queues > 24 > /sys/module/null_blk/parameters/use_lightnvm > N > /sys/module/null_blk/parameters/use_per_node_hctx > N > > $ fio --group_reporting --rw=randread --bs=4k --numjobs=24 > --iodepth=32 --runtime=99999999 --time_based --loops=1 > --ioengine=libaio --direct=1 --invalidate=1 --randrepeat=1 > --norandommap --exitall --name task_nullb0 --filename=/dev/nullb0 > task_nullb0: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, > ioengine=libaio, iodepth=32 > ... > fio-2.1.10 > Starting 24 processes > Jobs: 24 (f=24): [rrrrrrrrrrrrrrrrrrrrrrrr] [0.0% done] > [7234MB/0KB/0KB /s] [1852K/0/0 iops] [eta 1157d:09h:46m:22s] Thanks, the number of fio threads was pretty important. I'm still seeing better IOPs with queue_mode=0 (bio-based). Jobs: 24 (f=24): [r(24)] [11.7% done] [11073MB/0KB/0KB /s] [2835K/0/0 iops] [eta 14m:42s] (with queue_mode=2 I get ~1930K IOPs.. which I need to use to stack request-based DM multipath ontop) Now I can focus on why dm-multipath is slow...