KVM - User contributions [en]

Tuning KVM

2012-09-05T17:49:03Z

AnthonyLiguori:

== CPU Performance ==

Modern processors come with a wide variety of performance enhancing features such as streaming instructions sets (sse) and other performance-enhancing instructions. These features vary from processor to processor.

QEMU and KVM default to a compatible subset of cpu features, so that if you change your host processor, or perform a live migration, the guest will see its cpu features unchanged. This is great for compatibility but comes at a performance cost.

To pass all available host processor features to the guest, use the command line switch

qemu '''-cpu host'''

if you wish to retain compatibility, you can expose selected features to your guest. If all your hosts have these features, compatibility is retained:

qemu '''-cpu qemu64,+ssse3,+sse4.1,+sse4.2,+x2apic'''

To see the difference between the capabilities of the host CPU versus the guest, just compare the output of the following commands on each system:

cat /proc/cpuinfo | grep flags | uniq

For example, the default setting on a 64 bit host machine is "-cpu qemu64". This includes the following flags:

fpu de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx lm up pni hypervisor

The host itself might support other flags like cx16, mmxext, and so on.

See [http://blog.incase.de/index.php/cpu-feature-flags-and-their-meanings/ CPU Feature Flags And Their Meanings] (and other resources on the web) for more information.

== Networking ==

QEMU defaults to user-mode networking (slirp), which is available without prior setup and without administrative privileges on the host. It is also unfortunately very slow. To get high performance networking, switch to a bridged setup via the -net tap command line switches.

qemu -net nic,model=virtio,mac=... '''-net tap,ifname=...'''

QEMU also defaults to the RTL8139 network interface card (NIC) model. Again this card is compatible with most guests, but does not offer the best performance. If your guest supports it, switch to the virtio model:

qemu -net nic,'''model=virtio''',mac=... -net tap,ifname=...

== Storage ==

QEMU supports a wide variety for storage formats and back-ends. Easiest to use are the raw and qcow2 formats, but for the best performance it is best to use a raw partition. You can create either a logical volume or a partition and assign it to the guest:

qemu -drive '''file=/dev/mapper/ImagesVolumeGroup-Guest1''',cache=none,if=virtio

QEMU also supports a wide variety of caching modes. If you're using raw volumes or partitions, it is best to avoid the cache completely, which reduces data copies and bus traffic:

qemu -drive file=/dev/mapper/ImagesVolumeGroup-Guest1,'''cache=none''',if=virtio

As with networking, QEMU supports several storage interfaces. The default, IDE, is highly supported by guests but may be slow, especially with disk arrays. If your guest supports it, use the virtio interface:

qemu -drive file=/dev/mapper/ImagesVolumeGroup-Guest1,cache=none,'''if=virtio'''

Don't use the linux filesystem btrfs on the host for the image files. It will result in low IO performance. The kvm guest may even freeze when high IO traffic is done on the guest.

File:2011-forum-qemu-keynote-liguori.odp

2011-08-13T17:42:11Z

AnthonyLiguori:

File:2011-forum-qapi-liguori.odp

2011-08-13T01:12:38Z

AnthonyLiguori:

KVM Forum 2010

2010-08-19T00:52:29Z

AnthonyLiguori:

=Information on the upcoming KVM Forum 2010=
==KVM Forum 2010 (Aug 9-10, 2010)==
The place to be if you are interested in or involved with KVM development. Come together, talk about the current and future state of KVM. Learn. Share ideas. Influence the future of KVM.
==CFP==
[[KvmForum2010CFP|KVM Forum 2010 CFP]] (now closed, see [[#Schedule|Schedule]])
==Registration==
The KVM Forum 2010 is co-located with the Linux Foundation's LinuxCon in Boston.
Registration for the KVM Forum also includes full entrance to LinuxCon.

[http://events.linuxfoundation.org/component/registrationpro/?func=details&did=34 Register.]
==Hotel & Travel==
The KVM Forum 2010 will be held with LinuxCon at the [http://www.marriott.com/hotels/travel/boswf-renaissance-boston-waterfront-hotel/ Renaissance Boston Waterfront].

For all the details, including conference hotel discount and online reservations, check the [http://events.linuxfoundation.org/events/linuxcon/hotel LinuxCon Travel and Hotel] page.

==Presentations==
'''Monday, August 9th'''
{|
! Title !! Speaker !! Video
|-
|[[ Media:2010-forum-keynote.pdf | Keynote]] || Avi Kivity ||
|-
| [[Media:2010-forum-spice.pdf | Desktop virtualization with spice]] || Gerd Hoffman ||
|-
| [[Media:2010-forum-Kvm-autotest.pdf | Developing tests for the KVM autotest framework]] || Lucas Meneghel Rodrigues ||
|-
| [[Media:2010-forum-threading-qemu.pdf | Threading the QEMU Device Model]] || Anthony Liguori ||
|-
| [[Media:2010-forum-armbru-qdev.pdf | QEMU's new device model qdev ]] || Markus Armbruster ||
|-
| [[Media:2010-forum-PowerPC_KVM.pdf | KVM on Server Class PowerPC ]] || Alexander Graf ||
|-
| [[Media:2010-forum-thp.pdf | Transparent Hugepage Support ]] || Andrea Arcangeli ||
|-
| [[Media:2010-forum-migration.pdf | Migration: how to hop from machine to machine without losing state ]] || Juan Quintela ||
|-
| [[Media:2010-forum-sheepdog.pdf | Sheepdog: distributed storage system for QEMU ]] || Kazutaka Morita ||
|-
| [[Media:2010-forum-time-keeping.pdf | How to keep time correctly, and avoid SDR-awk cab emit peek problems ]] || Glauber Costa ||
|-
| [[Media:2010-forum-joro-pv-iommu.pdf | PV-DMA using IOMMU Emulation ]] || Joerg Roedel ||
|-
| [[Media:2010-forum-arnd-network-virt.pdf | Network Virtualization in KVM ]] || Arnd Bergmann ||
|-
| [[Media:Kvm10_ganeti_talk.pdf | Ganeti as a KVM cluster management interface ]] || Guido Trotter ||
|-
| [[Media:2010-forum-VirtIO-on-PowerVM.pdf | Porting virtio to PowerVM Hypervisors ]] || Ricardo Marin Matinata ||
|-
|}
'''Tuesday, August 10th'''
{|
! Title !! Speaker !! Video
|-
| [[Media:2010-kvm-forum-Liguori_keynote_v1.pdf | Keynote ]] || Anthony Liguori ||
|-
| [[Media:2010-forum-vhost_virtio_net_need_for_speed_2.pdf | vhost-net and virtio-net: need for speed ]] || Michael S. Tsirkin ||
|-
| [[Media:2010-forum-qmp-status-talk.pp.pdf | The QEMU Monitor Protocol (QMP) ]] || Luiz Fernando Nogueira Capitulino ||
|-
| [[Media:2010-kvm-forum-2010-integrating-with-linux.pdf | Integrating KVM with Linux ]] || Avi Kivity ||
|-
| [[Media:2010-kvm-forum-Embedded-KVM.pdf | KVM in Embedded: Requirements, Experiences and Open Challenges ]] || Jan Kiszka ||
|-
| [[Media:0.5.kemari-kvm-forum-2010.pdf | Kemari: Fault Tolerant Virtual Machine Synchronization based on KVM ]] || Yoshi Tamura ||
|-
| [[Media:2010-forum-litke-kvmforum2010.pdf | Managing Resources on Over-committed Virtualization Hosts ]] || Adam Litke ||
|-
| [[Media:2010-forum-mtosatti_walkthrough_entry_exit.pdf | A Walkthrough on some recent KVM performance improvements ]] || Marcelo Tosatti ||
|-
| [[Media:2010-forum-Nested-Friendly-KVM2.pdf | Examing KVM as Nested Virtualization Friendly Guest ]] || Eddie Dong ||
|-
| [[Media:Kvm-device-assignment.pdf | PCI direct device assignment: pwned! all your device are belong to guest ]] || Chris Wright ||
|-
| [[Media:2010-forum-perf-and-scalability-server-consolidation.pdf | Performance and Scalability of Server Consolidation using KVM ]] || Andrew Theurer ||
|-
| [[Media:WinKVM-KVMForum2010.pdf | WinKVM: Windows kernel-based Virtual Machine ]] || Kazushi Takahashi ||
|-
| [[Media:0.11.Nahanni-CamMacdonell.pdf | Nahanni: Inter-VM Shared Memory ]] || Cam Macdonell ||
|-
| [[Media:2010-forum-Async-page-faults.pdf | Asynchronous Page Faults: AIX did it. ]] || Gleb Natapov ||
|-
| [[Media: 2010-forum-Pci-express-in-qemu.pdf | PCI Express support in QEMU ]] || Isaku Yamahata ||
|-
|}

[[Image:Groupphoto.jpg|thumb|frame|KVM Forum 2010 Group Photo]]

[[:Image:GroupPhoto.JPG|Full size picture]]

'''Back Row:''' John Cooper, Jan Kiszka, Bill Burns, Kevin Wolf, Marcelo Tosatti, Gerd Hoffman, Jes Sorensen, Markus Armbruster, Vadim Rozenfeld, Adam Litke, Don Dutile, Daniel Berrange, Richard Jones, Rik van Riel

'''Middle Row:''' Chris Wright, Alex Graf, Andrea Arcangeli, Luiz Capitulino, Justin Forbes, Juan Quintela, Glauber Costa, Amit Shah, Alex Williamson, Ricardo Matinana

'''Front Row:''' Lucas Rodridgues, Eduardo Habkost, Paolo Bonzini, Gleb Natapov, Zach Amsden, Avi Kivity, Dor Laor, Anthony Liguori, Barak Azulay, Andrew Theurer, Dustin Kirkland, Ayal Baron

2007-04-21T03:12:10Z

AnthonyLiguori:

= Guest support status =
== Linux distributions ==
{| border="1" cellpadding="2" cellspacing="0"
| Host version
| Host cpu
| Host bitness
| Guest
| Guest bitness
| Status
| Comments
|
|-
| kvm-12
| Intel, AMD
| 64
| FC5
| 32, 64
| Works
|
|
|-
| kvm-12
| Intel, AMD
| 32
| FC5
| 32
| Works
|
|
|-
| kvm-12
| Intel, AMD
| 32
| FC6
| 32
| Works
|
|
|-
| kvm-12
| Intel
| 32
| Debian Sarge
| 32
| Works
|
|
|-
| kvm-12
| Intel
| 64
| Debian Etch
| 32, 64
| Works
|
|
|-
| kvm-12
| Intel
| 64
| Debian Sarge
| 32
| Mostly works
| Install hangs, will install via -no-kvm. Runs fine after
|
|-
| kvm-12
| Intel
| 64
| Trixbox (CentOS)
| 32
| Works
|
|
|-
| kvm-15
| Intel
| 64
| Slackware 11
| 32
| Works
| using test26.s kernel
|
|-
| kvm-17/18
| Intel
| 32
| [[OpenSuse]] 10.2
| 32
| Works
| sans gfxmenu
|
|-
| kvm-17/18
| Intel
| 32
| Qemu-Puppy 2.01-3
| 32
| Works
|
|
|-
| kvm-17/18
| Intel
| 32
| Qemu-Puppy 2.13-1
| 32
| Works
|
|
|-
| kvm-18
| Intel
| 64
| KNOPPIX 5.1.1
| 32
| Works
| wants nmi_watchdog=0 kernel parameter
|
|-
| kvm-18
| Intel
| 32
| Knoppix 5.2
| 32
| Works
|
|
|-
|<|>kvm-18
|<|>Intel
|<|>64
|<|>Ubuntu 7.04 beta
|<|>64
|<|>Works
| <^>Installation works with -no-kvm, except for grub. Grub fixed with sysrescuecd. Works fine...
|
|-
| kvm-19
| AMD
| 32
| Ubuntu 7.04
| 32
| Works
|
|
|-
|<|>kvm-18
|<|>Intel
|<|>64
|<|>[[SystemRescueCD]] 0.3.4
|<|>32
|<|>Works
| <^>Works fine, except for initial X-setting "cirrus" - changed to "vesa", then works.
|
|-
| kvm-18
| Intel
| 32
| Debian 4.0
| 32
| Works
| released version (netinst CD)
|
|}
== Windows Family ==
{| border="1" cellpadding="2" cellspacing="0"
| Host version
| Host cpu
| Host bitness
| Guest
| Guest bitness
| Status
| Comments
|
|-
| kvm-12
| Intel, AMD
| 64, 32
| Windows XP Pro
| 32
| Works
|
|
|-
| kvm-19, 2.6.20.7
| AMD
| 64, 32
| Windows 98SE
| 32
| Crashes
| Stops during boot. 100% CPU. Works with -no-kvm
|
|-
| kvm-19, 2.6.20.7
| AMD
| 64, 32
| Windows 95
| 32
| Crashes
| Stops during boot. 100% CPU. Works with -no-kvm, but doesn't recognize the NIC. Did no further testing.
|
|-
| kvm-14
| Intel
| 64
| Windows Server 2003 (Enterprise, SP2)
| 32
| Works
| Needs -no-kvm and -no-acpi for install and possibly for update to SP2. Use -net nic,model=rtl8139
|
|-
| kvm-14
| Intel
| 64
| Windows Vista (Business, Enterprise)
| 32, 64
| Fails to install
| ACPI support is required for installation, and enabling ACPI support causes a bluescreen
|
|-
| kvm-17/18
| Intel
| 64, 32
| Windows XP Pro (SP2)
| 32
| Works
| Use the [[Windows_ACPI_Workaround]] (possibly booting from qemu to change) if it boots to a black screen
|
|-
| kvm-20 (unreleased)
| Intel
| 32
| Windows 2000 Pro (SP4)
| 32
| Works
| Install with -no-acpi
|
|}
== BSD ==
{| border="1" cellpadding="2" cellspacing="0"
| Host version
| Host cpu
| Host bitness
| Guest
| Guest bitness
| Status
| Comments
|
|-
| kvm-12
| Intel
| 64
| OpenBSD 4.0
| 64
| Works
|
|
|-
| kvm-16 + CVS
| Intel
| 64
| OpenBSD 4.0
| 32
| Works
|
|
|-
| kvm-12
| AMD
| 64
| FreeBSD 6.2
| 64
| Works
|
|
|-
| kvm-16 + CVS
| AMD
| 64
| FreeBSD 6.2
| 32
| Works
|
|
|-
| kvm-15
| AMD
| 64
| GNU/kFreeBSD
| 64
| Works
|
|
|-
| kvm-16 + CVS
| AMD
| 64
| GNU/kFreeBSD
| 32
| Works
|
|
|-
| kvm-17/18
| Intel
| 32
| FreeBSD 6.1
| 32
| Works
|
|
|-
| kvm-17/18
| Intel
| 32
| NetBSD 3.1
| 32
| Works
|
|
|}
== Others ==
{| border="1" cellpadding="2" cellspacing="0"
| Host version
| Host cpu
| Host bitness
| Guest
| Guest bitness
| Status
| Comments
|
|-
| kvm-12
| AMD
| 64
| Haiku OS
| 32
| Works
| [http://kvm.qumranet.com/kvmwiki/Screenshots?action=AttachFile&do=view&target=kvm_aros_haiku.png screenshot]
|
|-
| kvm-12
| AMD
| 64
| Amiga Research OS (AROS)
| 32
| Works
| LiveCD tested. [http://kvm.qumranet.com/kvmwiki/Screenshots?action=AttachFile&do=view&target=kvm_aros_haiku.png screenshot]
|
|-
| kvm-14
| AMD
| 64
| ReactOS 0.3.0
| 32
| Works
| [http://kvm.qumranet.com/kvmwiki/Screenshots?action=AttachFile&do=view&target=kvm_reactos.png screenshot]
|
|-
| kvm-12
| Intel
| 64
| Solaris 10 GA U3
| 64
| Works
| [http://kvm.qumranet.com/kvmwiki/Screenshots?action=AttachFile&do=view&target=solaris10-fc6-login.png screenshot]
|
|-
| kvm-12/14
| Intel
| 64
| FreeDOS 1.0
| 32
| Work(ish)
| Can only be installed from live CD by disabling kvm and using qemu only. Upper memory management (himem.exe) crashed kvm. Some other drivers do so as well. Step through booting using F8 to determine which. DOS is confined to the lower 640K of memory. See bug 1666308.
|
|-
| kvm-17/18
| Intel
| 32
| Solaris 10.1
| 32
| Works
| Complains about clock speed
|
|-
| kvm-18
| Intel
| 64
| Xen 3.0.4
| 64, 32
| Works
|
|
|-
| kvm-18
| Intel
| 32
| Solaris 11
| 32
| Works
|

__NOTOC__