Date: Thu, 16 Jan 2014 19:38:02 +0100 From: Sydney Meyer <meyer.sydney@googlemail.com> To: freebsd-virtualization@freebsd.org Subject: Re: Xen PVHVM with FreeBSD10 Guest Message-ID: <F672F9F6-7F85-4315-AFA0-EA18527A1893@googlemail.com> In-Reply-To: <51F93577-E5A2-4237-9EDD-A89DDA5FC428@gmail.com> References: <9DF57091-9957-452D-8A15-C2267F66ABEC@googlemail.com> <52D81009.6050603@citrix.com> <51F93577-E5A2-4237-9EDD-A89DDA5FC428@gmail.com>
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Well then, thanks for the hint.. dmesg shows the following: Jan 16 18:22:30 bsd10 kernel: xn0: <Virtual Network Interface> at device/vif/0 on xenbusb_front0 Jan 16 18:22:30 bsd10 kernel: xn0: Ethernet address: 00:16:3e:df:1b:5a Jan 16 18:22:30 bsd10 kernel: xenbusb_back0: <Xen Backend Devices> on xenstore0 Jan 16 18:22:30 bsd10 kernel: xn0: backend features: feature-sg feature-gso-tcp4 Jan 16 18:22:30 bsd10 kernel: xbd0: 8192MB <Virtual Block Device> at device/vbd/768 on xenbusb_front0 Jan 16 18:22:30 bsd10 kernel: xbd0: attaching as ada0 Jan 16 18:22:30 bsd10 kernel: xbd0: features: flush, write_barrier Jan 16 18:22:30 bsd10 kernel: xbd0: synchronize cache commands enabled. Now i did some tests with raw images and the disk performs very well (10-15% less than native throughput). Is this a known problem or maybe specific to this constellation? The Test System is running on a Haswell Intel Core i3 CPU (4310T) with an Intel H81 Chipset. Cheers, Sydney. On 16.01.2014, at 18:06, Sydney Meyer <meyer.sydney@googlemail.com> wrote: > No, the VMs are running on local LVM Volumes as Disk Backend. > >> On 16 Jan 2014, at 17:59, Roger Pau Monné <roger.pau@citrix.com> wrote: >> >>> On 16/01/14 17:41, Sydney Meyer wrote: >>> Hello everyone, >>> >>> does someone know how to check if the paravirtualized I/O drivers from Xen are loaded/working in FreeBSD 10? To my understanding it isn't necessary anymore to compile a custom kernel with PVHVM enabled, right? In /var/log/messages/ I can see the XN* and XBD* devices and the network performance is very good (saturated Gb) compared to qemu-emulated, but the disk performance is not as well, infact, it is even slower than emulated with qemu (0.10.2). I did some test with dd and bonnie++, turned caching on the host off and tried to directly sync to disk, PVonHVM is averagely 15-20 % slower than QEMU at throughput. Both VM's are running on the same host on a Xen 4.1 Hypervisor with QEMU 0.10.2 on a Debian Linux 3.2 Kernel as Dom0. >> >> PV drivers will be used automatically if Xen is detected. You should see >> something like this on dmesg: >> >> xn0: <Virtual Network Interface> at device/vif/0 on xenbusb_front0 >> xn0: Ethernet address: 00:16:3e:47:d4:52 >> xenbusb_back0: <Xen Backend Devices> on xenstore0 >> xn0: backend features: feature-sg feature-gso-tcp4 >> xbd0: 20480MB <Virtual Block Device> at device/vbd/51712 on xenbusb_front0 >> xbd0: features: flush, write_barrier >> xbd0: synchronize cache commands enabled. >> >> Are you using a raw file as a disk? >> >> Roger. >>
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