From: Peter Lieven <pl@dlh.net>
To: Gleb Natapov <gleb@redhat.com>
Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: Re: [Qemu-devel] win7 bad i/o performance, high insn_emulation and exists
Date: Mon, 20 Feb 2012 20:24:23 +0100 [thread overview]
Message-ID: <4F429DE7.7070803@dlh.net> (raw)
In-Reply-To: <20120220190449.GG29601@redhat.com>
On 20.02.2012 20:04, Gleb Natapov wrote:
> On Mon, Feb 20, 2012 at 08:40:08PM +0200, Gleb Natapov wrote:
>> On Mon, Feb 20, 2012 at 07:17:55PM +0100, Peter Lieven wrote:
>>> Hi,
>>>
>>> I came a across an issue with a Windows 7 (32-bit) as well as with a
>>> Windows 2008 R2 (64-bit) guest.
>>>
>>> If I transfer a file from the VM via CIFS or FTP to a remote machine,
>>> i get very poor read performance (around 13MB/s). The VM peaks at 100%
>>> cpu and I see a lot of insn_emulations and all kinds of exists in kvm_stat
>>>
>>> efer_reload 0 0
>>> exits 2260976 79620
>>> fpu_reload 6197 11
>>> halt_exits 114734 5011
>>> halt_wakeup 111195 4876
>>> host_state_reload 1499659 60962
>>> hypercalls 0 0
>>> insn_emulation 1577325 58488
>>> insn_emulation_fail 0 0
>>> invlpg 0 0
>>> io_exits 943949 40249
>> Hmm, too many of those.
>>
>>> irq_exits 108679 5434
>>> irq_injections 236545 10788
>>> irq_window 7606 246
>>> largepages 672 5
>>> mmio_exits 460020 16082
>>> mmu_cache_miss 119 0
>>> mmu_flooded 0 0
>>> mmu_pde_zapped 0 0
>>> mmu_pte_updated 0 0
>>> mmu_pte_write 13474 9
>>> mmu_recycled 0 0
>>> mmu_shadow_zapped 141 0
>>> mmu_unsync 0 0
>>> nmi_injections 0 0
>>> nmi_window 0 0
>>> pf_fixed 22803 35
>>> pf_guest 0 0
>>> remote_tlb_flush 239 2
>>> request_irq 0 0
>>> signal_exits 0 0
>>> tlb_flush 20933 0
>>>
>>> If I run the same VM with a Ubuntu 10.04.4 guest I get around 60MB/s
>>> throughput. The kvm_stats look a lot more sane.
>>>
>>> efer_reload 0 0
>>> exits 6132004 17931
>>> fpu_reload 19863 3
>>> halt_exits 264961 3083
>>> halt_wakeup 236468 2959
>>> host_state_reload 1104468 3104
>>> hypercalls 0 0
>>> insn_emulation 1417443 7518
>>> insn_emulation_fail 0 0
>>> invlpg 0 0
>>> io_exits 869380 2795
>>> irq_exits 253501 2362
>>> irq_injections 616967 6804
>>> irq_window 201186 2161
>>> largepages 1019 0
>>> mmio_exits 205268 0
>>> mmu_cache_miss 192 0
>>> mmu_flooded 0 0
>>> mmu_pde_zapped 0 0
>>> mmu_pte_updated 0 0
>>> mmu_pte_write 7440546 0
>>> mmu_recycled 0 0
>>> mmu_shadow_zapped 259 0
>>> mmu_unsync 0 0
>>> nmi_injections 0 0
>>> nmi_window 0 0
>>> pf_fixed 38529 30
>>> pf_guest 0 0
>>> remote_tlb_flush 761 1
>>> request_irq 0 0
>>> signal_exits 0 0
>>> tlb_flush 0 0
>>>
>>> I use virtio-net (with vhost-net) and virtio-blk. I tried disabling
>>> hpet (which basically illiminated the mmio_exits, but does not
>>> increase
>>> performance) and also commit (39a7a362e16bb27e98738d63f24d1ab5811e26a8
>>> ) - no improvement.
>>>
>>> My commandline:
>>> /usr/bin/qemu-kvm-1.0 -netdev
>>> type=tap,id=guest8,script=no,downscript=no,ifname=tap0,vhost=on
>>> -device virtio-net-pci,netdev=guest8,mac=52:54:00:ff:00:d3 -drive format=host_device,file=/dev/mapper/iqn.2001-05.com.equallogic:0-8a0906-eeef4e007-a8a9f3818674f2fc-lieven-windows7-vc-r80788,if=virtio,cache=none,aio=native
>>> -m 2048 -smp 2 -monitor tcp:0:4001,server,nowait -vnc :1 -name
>>> lieven-win7-vc -boot order=dc,menu=off -k de -pidfile
>>> /var/run/qemu/vm-187.pid -mem-path /hugepages -mem-prealloc -cpu
>>> host -rtc base=localtime -vga std -usb -usbdevice tablet -no-hpet
>>>
>>> What further information is needed to debug this further?
>>>
>> Which kernel version (looks like something recent)?
>> Which host CPU (looks like something old)?
> Output of cat /proc/cpuinfo
>
>> Which Windows' virtio drivers are you using?
>>
>> Take a trace like described here http://www.linux-kvm.org/page/Tracing
>> (with -no-hpet please).
>>
> And also "info pci" output from qemu monitor while we are at it.
here we go. i stumbled across IRQ 0 ?
QEMU 1.0 monitor - type 'help' for more information
(qemu) info pci
info pci
Bus 0, device 0, function 0:
Host bridge: PCI device 8086:1237
id ""
Bus 0, device 1, function 0:
ISA bridge: PCI device 8086:7000
id ""
Bus 0, device 1, function 1:
IDE controller: PCI device 8086:7010
BAR4: I/O at 0xc080 [0xc08f].
id ""
Bus 0, device 1, function 2:
USB controller: PCI device 8086:7020
IRQ 5.
BAR4: I/O at 0xc040 [0xc05f].
id ""
Bus 0, device 1, function 3:
Bridge: PCI device 8086:7113
IRQ 9.
id ""
Bus 0, device 2, function 0:
VGA controller: PCI device 1234:1111
BAR0: 32 bit prefetchable memory at 0xfd000000 [0xfdffffff].
BAR6: 32 bit memory at 0xffffffffffffffff [0x0000fffe].
id ""
Bus 0, device 3, function 0:
Ethernet controller: PCI device 1af4:1000
IRQ 0.
BAR0: I/O at 0xc060 [0xc07f].
BAR1: 32 bit memory at 0xfebf0000 [0xfebf0fff].
BAR6: 32 bit memory at 0xffffffffffffffff [0x0000fffe].
id ""
Bus 0, device 4, function 0:
SCSI controller: PCI device 1af4:1001
IRQ 0.
BAR0: I/O at 0xc000 [0xc03f].
BAR1: 32 bit memory at 0xfebf1000 [0xfebf1fff].
id ""
>> Try to use -cpu host,+x2apic. It may help Linux guest performance.
>>
>> --
>> Gleb.
>> --
>> To unsubscribe from this list: send the line "unsubscribe kvm" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
> --
> Gleb.
next prev parent reply other threads:[~2012-02-20 19:24 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-20 18:17 [Qemu-devel] win7 bad i/o performance, high insn_emulation and exists Peter Lieven
2012-02-20 18:40 ` Gleb Natapov
2012-02-20 19:04 ` Gleb Natapov
2012-02-20 19:24 ` Peter Lieven [this message]
2012-02-20 19:59 ` Peter Lieven
2012-02-20 20:45 ` Gleb Natapov
2012-02-21 10:50 ` Peter Lieven
2012-02-21 10:56 ` Gleb Natapov
2012-02-21 10:59 ` Peter Lieven
2012-02-21 11:00 ` Gleb Natapov
2012-02-21 11:16 ` Peter Lieven
2012-02-21 11:46 ` Gleb Natapov
2012-02-21 12:05 ` Peter Lieven
2012-02-21 13:56 ` Vadim Rozenfeld
2012-02-21 14:10 ` Peter Lieven
2012-02-21 16:48 ` Vadim Rozenfeld
2012-02-21 18:21 ` Peter Lieven
2012-02-20 19:15 ` Peter Lieven
2012-02-20 20:42 ` Gleb Natapov
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