Re: Xen PVHVM with FreeBSD10 Guest
On 16/01/14 19:38, Sydney Meyer wrote: 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). So the problem only manifest itself when using block devices as disk backends? I've done some tests with fio using direct=1 (and a LVM volume as the backend), and it shows that disk writes are slower when using PV drivers instead of the emulated ones. On the other hand disk reads are faster when using the PV drivers. Have you tried if the 9.x series also show the same behaviour? (you will have to compile the custom XENHVM kernel) Roger. ___ freebsd-virtualization@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization To unsubscribe, send any mail to freebsd-virtualization-unsubscr...@freebsd.org
Re: Xen PVHVM with FreeBSD10 Guest
On 17/01/14 10:17, Sydney Meyer wrote: I’m doing some benchmarks with bonnie and dd on the Variations 9.2/10.0;PVHVM/VirtIO;fileio/blockio. I will post the results here to this thread. By VirtIO I guess you mean emulated IO? That sounds great, I'm eager to see the results :) Roger. ___ freebsd-virtualization@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization To unsubscribe, send any mail to freebsd-virtualization-unsubscr...@freebsd.org
Xen PVHVM with FreeBSD10 Guest
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. ___ freebsd-virtualization@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization To unsubscribe, send any mail to freebsd-virtualization-unsubscr...@freebsd.org
Re: Xen PVHVM with FreeBSD10 Guest
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. ___ freebsd-virtualization@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization To unsubscribe, send any mail to freebsd-virtualization-unsubscr...@freebsd.org
Re: Xen PVHVM with FreeBSD10 Guest
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.syd...@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@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. ___ freebsd-virtualization@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization To unsubscribe, send any mail to freebsd-virtualization-unsubscr...@freebsd.org
