From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Worley Subject: Re: [Scst-devel] [ofa-general] WinOF_2_0_5/SRP initiator: slow reads and eventually hangs Date: Mon, 14 Sep 2009 17:03:04 -0600 Message-ID: References: <4AA4F561.504@vlnb.net> <4AAE909F.6030202@vlnb.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <4AAE909F.6030202-d+Crzxg7Rs0@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Vladislav Bolkhovitin Cc: Bart Van Assche , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, scst-devel , OpenIB List-Id: linux-rdma@vger.kernel.org On Mon, Sep 14, 2009 at 12:51 PM, Vladislav Bolkhovitin = wrote: > Chris Worley, on 09/11/2009 11:50 PM wrote: >> >> I've definitely removed the switch/firmware from being the cause. >> >> I'm thinking the reason you can't repeat the test may be latency >> related. =A0We get ~50usecs average latency (on small block sizes), >> which can't be achieved using regular SSD's (and rotating drives are >> nowhere close). =A0Maybe a ramdisk would help repeat the issue. > > I think you should try to reproduce the problem with ramdisk or nulli= o. By > so you will eliminate possible influence of the SSD backend. W/ 12GB RAM in the target, I created a 7GB ramdisk: mount -t ramfs -o size=3D7g ramfs /mnt/ dd if=3D/dev/zero of=3D/mnt/foo bs=3D1024k count=3D7000 echo "open ramdisk /mnt/foo" > /proc/scsi_tgt/vdisk/vdisk echo "add ramdisk 2" >/proc/scsi_tgt/groups/Default/devices Then, on the initiator, I tested it... and it hung during sequential 8KB block reads: fio --rw=3Dread --bs=3D8k --numjobs=3D64 --iodepth=3D64 --sync=3D0 --di= rect=3D1 --randrepeat=3D0 \ --group_reporting --ioengine=3Dlibaio --filename=3D/dev/sde --name=3D= test --loops=3D10000 --runtime=3D600 Note that I was running the SM on the target this time too. Thanks, Chris > > Vlad > -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html