From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:42117) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SzoRI-0006C8-Ul for qemu-devel@nongnu.org; Fri, 10 Aug 2012 08:35:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SzoRG-00020Z-3N for qemu-devel@nongnu.org; Fri, 10 Aug 2012 08:35:40 -0400 Received: from mail.profihost.ag ([85.158.179.208]:59047) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SzoRF-00020Q-OX for qemu-devel@nongnu.org; Fri, 10 Aug 2012 08:35:38 -0400 Message-ID: <50250017.9070000@profihost.ag> Date: Fri, 10 Aug 2012 14:35:35 +0200 From: Stefan Priebe - Profihost AG MIME-Version: 1.0 References: <502283FA.2080506@profihost.ag> <5022912B.2000607@redhat.com> <50235527.4090804@profihost.ag> <50236059.7060801@redhat.com> <4A799203-5BFF-4DE9-9B85-459096EBEC22@profihost.ag> <50236484.2090702@redhat.com> <502369C7.7000300@profihost.ag> <50238E2A.1050203@profihost.ag> <5024D2E7.40700@profihost.ag> <5024E06A.4070603@redhat.com> <5024E232.5020706@profihost.ag> <5024E2CB.2050208@redhat.com> <5024F73E.2060609@profihost.ag> <5024FB17.7060706@profihost.ag> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] virtio-scsi vs. virtio-blk List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: ronnie sahlberg Cc: Paolo Bonzini , qemu-devel , Stefan Hajnoczi Am 10.08.2012 14:24, schrieb ronnie sahlberg: > On Fri, Aug 10, 2012 at 10:14 PM, Stefan Priebe - Profihost AG > wrote: > I dont know the kvm version numbers. They're the same as qemu. > But you can check the file > block/iscsi.c for the version you use for this : > > .bdrv_aio_discard = iscsi_aio_discard, # grep 'scsi_aio_discard' block/iscsi.c iscsi_aio_discard(BlockDriverState *bs, .bdrv_aio_discard = iscsi_aio_discard, => so yes > If it has bdrv_aio_discard then you have support for 'discard' when > using the scsi emulation. i.e. -drive ...,if=scsi,... > > #ifdef __linux__ > .bdrv_ioctl = iscsi_ioctl, > .bdrv_aio_ioctl = iscsi_aio_ioctl, > #endif yes too. > If it has these two lines too, then you have scsi-passthrough and can > bypass the qemu scsi emulation. > One way to activate passthough is via scsi-generic: > Example: > -device lsi -device scsi-generic,drive=MyISCSI \ > -drive file=iscsi://10.1.1.125/iqn.ronnie.test/1,if=none,id=MyI When i do this the guest system always uses the sym53c8xx kernel module. This results in 70 iops instead of 30000 iops. Is this really correct that it uses the very old sym53c8xx kernel module for this device? used start command: http://pastebin.com/raw.php?i=23fkaQgc dmesg from guest: dmesg|egrep "sym|scsi" [ 0.000000] Linux version 3.5.0intel (root@neuertestswerverscsi) (gcc version 4.4.5 (Debian 4.4.5-8) ) #5 SMP Thu Aug 9 20:27:29 CEST 2012 [ 0.291949] scsi0 : ata_piix [ 0.292109] scsi1 : ata_piix [ 0.495217] sym0: <895a> rev 0x0 at pci 0000:00:03.0 irq 10 [ 0.498694] sym0: No NVRAM, ID 7, Fast-40, LVD, parity checking [ 0.500565] sym0: SCSI BUS has been reset. [ 0.508603] scsi2 : sym-2.2.3 [ 3.512544] sym0: unknown interrupt(s) ignored, ISTAT=0x5 DSTAT=0x80 SIST=0x0 [ 3.514004] scsi 2:0:0:0: Direct-Access NEXENTA NEXENTASTOR 1.0 PQ: 0 ANSI: 5 [ 3.514414] scsi target2:0:0: tagged command queuing enabled, command queue depth 16. [ 3.514820] scsi target2:0:0: Beginning Domain Validation [ 3.518370] scsi target2:0:0: Domain Validation skipping write tests [ 3.518772] scsi target2:0:0: Ending Domain Validation Thanks a lot! Stefan