Date: Wed, 17 Aug 2016 12:15:21 +0200 From: Roger Pau =?iso-8859-1?Q?Monn=E9?= <roger.pau@citrix.com> To: <rainer@ultra-secure.de> Cc: <freebsd-xen@freebsd.org>, <owner-freebsd-xen@freebsd.org> Subject: Re: Is it me or is FreeBSD slower on Xen than Linux? Message-ID: <20160817101521.e3sekmopltmbuujr@mac> In-Reply-To: <bb5c6eca16d24e230151331f48580d71@ultra-secure.de> References: <20160816132938.d2i4u2y3scpzi2et@mac> <00D22384-BAA7-42E4-A486-4BE07562D011@sarenet.es> <8521aebaa093bcefe5956a71fd879140@ultra-secure.de> <872C5626-F58D-4F84-92AC-88B7352D1DDF@sarenet.es> <c6bdef83f2370173c067820565bf933e@ultra-secure.de> <20160816141826.56mxsgx6e7rynxqg@mac> <cff064d12c783cc6eebba4b56f063ba7@ultra-secure.de> <599395934f751784b1f842ed3c8f879c@ultra-secure.de> <20160817091229.hm5a66ftwnfoj7vx@mac> <bb5c6eca16d24e230151331f48580d71@ultra-secure.de>
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On Wed, Aug 17, 2016 at 11:29:17AM +0200, rainer@ultra-secure.de wrote: > Am 2016-08-17 11:12, schrieb Roger Pau Monné: > > > No, I don't think so, this is what I get using a slow USB 2.0 disk as > > the > > backend: (on Dom0 I get something between 70-80M/s, so there isn't much > > difference). > > > > # dc3dd wipe=/dev/ada1 > > > > dc3dd 7.2.641 started at 2016-08-17 09:03:26 +0000 > > compiled options: > > command line: dc3dd wipe=/dev/ada1 > > device size: 2097152 sectors (probed), 1,073,741,824 bytes > > sector size: 512 bytes (probed) > > 1073741824 bytes ( 1 G ) copied ( 100% ), 16 s, 65 M/s > > > > input results for pattern `00': > > 2097152 sectors in > > > > output results for device `/dev/ada1': > > 2097152 sectors out > > > > dc3dd completed at 2016-08-17 09:03:42 +0000 > > > > > What may I be doing wrong? > > > > TBH it's hard to tell, I don't know of any option that could cause this > > disk > > performance degradation. Do you also have ada* devices apart from the > > xbd* > > ones? I don't think it's going to make any difference, but could you try > > with the ada* block devices instead? > > > Strange thing is, I have ada devices for the the other disks, but this one > didn't show up as ada-device. The fact that it shows up as ada or xbd depends on what you specify in the guest config file (hd* will show up as ada, while xvd* will show up as xbd*). I don't know how/if XenServer allows you to specify the vdev in the guest configuration. > On my FreeBSD11 Test VM, the disk didn't show up until I rebooted, even > though I (believe to) have the xen-guest stuff installed: > > (freebsd11 </root>) 0 # ps ax |grep xe-d > 694 v0- I 0:00.00 /bin/sh /usr/local/sbin/xe-daemon -p > /var/run/xe-daemon.pid > 2202 0 R+ 0:00.00 grep xe-d > (freebsd11 </root>) 0 # pkg info|grep xe- > xe-guest-utilities-6.2.0_2 FreeBSD VM tools for Citrix XenServer and XCP > (freebsd11 </root>) 0 # pkg info|grep xen > xen-guest-tools-4.6.1 Xen tools within FreeBSD domU > > I have an ada device there and I got about 10MB/s on wipe. At least in the > beginning. Hm, so performance is more or less the same. Having the xen-guest stuff should not make a difference regarding disks, this is IIRC only used when migrating a VM. > (freebsd11 </root>) 0 # sysctl -a |grep xen > kern.vm_guest: xen > device xenpci > vfs.pfs.vncache.maxentries: 0 > dev.xenbusb_back.0.%parent: xenstore0 > dev.xenbusb_back.0.%pnpinfo: > dev.xenbusb_back.0.%location: > dev.xenbusb_back.0.%driver: xenbusb_back > dev.xenbusb_back.0.%desc: Xen Backend Devices > dev.xenbusb_back.%parent: > dev.xn.0.xenstore_peer_path: /local/domain/0/backend/vif/245/0 > dev.xn.0.xenbus_peer_domid: 0 > dev.xn.0.xenbus_connection_state: Connected > dev.xn.0.xenbus_dev_type: vif > dev.xn.0.xenstore_path: device/vif/0 > dev.xn.0.%parent: xenbusb_front0 > dev.xbd.1.xenstore_peer_path: /local/domain/0/backend/vbd3/245/768 > dev.xbd.1.xenbus_peer_domid: 0 > dev.xbd.1.xenbus_connection_state: Connected > dev.xbd.1.xenbus_dev_type: vbd > dev.xbd.1.xenstore_path: device/vbd/768 > dev.xbd.1.%parent: xenbusb_front0 > dev.xbd.0.xenstore_peer_path: /local/domain/0/backend/vbd3/245/832 > dev.xbd.0.xenbus_peer_domid: 0 > dev.xbd.0.xenbus_connection_state: Connected > dev.xbd.0.xenbus_dev_type: vbd > dev.xbd.0.xenstore_path: device/vbd/832 > dev.xbd.0.%parent: xenbusb_front0 > dev.xenbusb_front.0.%parent: xenstore0 > dev.xenbusb_front.0.%pnpinfo: > dev.xenbusb_front.0.%location: > dev.xenbusb_front.0.%driver: xenbusb_front > dev.xenbusb_front.0.%desc: Xen Frontend Devices > dev.xenbusb_front.%parent: > dev.xs_dev.0.%parent: xenstore0 > dev.xctrl.0.%parent: xenstore0 > dev.xenballoon.0.%parent: xenstore0 > dev.xenballoon.0.%pnpinfo: > dev.xenballoon.0.%location: > dev.xenballoon.0.%driver: xenballoon > dev.xenballoon.0.%desc: Xen Balloon Device > dev.xenballoon.%parent: > dev.debug.0.%parent: xenpv0 > dev.privcmd.0.%parent: xenpv0 > dev.evtchn.0.%parent: xenpv0 > dev.xenstore.0.%parent: xenpv0 > dev.xenstore.0.%pnpinfo: > dev.xenstore.0.%location: > dev.xenstore.0.%driver: xenstore > dev.xenstore.0.%desc: XenStore > dev.xenstore.%parent: > dev.xen_et.0.%parent: xenpv0 > dev.xen_et.0.%pnpinfo: > dev.xen_et.0.%location: > dev.xen_et.0.%driver: xen_et > dev.xen_et.0.%desc: Xen PV Clock > dev.xen_et.%parent: > dev.granttable.0.%parent: xenpv0 > dev.xenpv.0.%parent: nexus0 > dev.xenpv.0.%pnpinfo: > dev.xenpv.0.%location: > dev.xenpv.0.%driver: xenpv > dev.xenpv.0.%desc: Xen PV bus > dev.xenpv.%parent: > dev.xenpci.0.%parent: pci0 > dev.xenpci.0.%pnpinfo: vendor=0x5853 device=0x0001 subvendor=0x5853 > subdevice=0x0001 class=0x010000 > dev.xenpci.0.%location: slot=3 function=0 dbsf=pci0:0:3:0 > handle=\_SB_.PCI0.S18_ > dev.xenpci.0.%driver: xenpci > dev.xenpci.0.%desc: Xen Platform Device > dev.xenpci.%parent: > dev.xen.xsd_kva: 18446735281894703104 > dev.xen.xsd_port: 3 > dev.xen.balloon.high_mem: 0 > dev.xen.balloon.low_mem: 0 > dev.xen.balloon.hard_limit: 18446744073709551615 > dev.xen.balloon.driver_pages: 0 > dev.xen.balloon.target: 2097152 > dev.xen.balloon.current: 2096128 > This looks fine AFAICT. > > Do you know what I could check on the dom0 side to make sure it's configured > right? Sadly XenServer uses a completely different disk backend from the Xen Open Source Project (which is what I work with). Could you try to ask on the XenServer mailing lists or forums[0]? I think there's a better chance you will find someone familiar with it there. Feel free to Cc me if you need input regarding the FreeBSD blkfront internals. Roger. [0] http://xenserver.org/
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