On Mon, Feb 20, 2012 at 08:59:38PM +0100, Peter Lieven wrote: > 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 is the output while i was tracing. you can download the trace > i took while i did a ftp transfer from the vm: > > -> http://82.141.21.156/report.txt.gz > Windows reads PM timer. A lot. 15152 times per second. Can you try to run this command in Windows guest: bcdedit /set {default} useplatformclock false I hope it will make Windows use TSC instead, but you can't be sure about anything with Windows :( > 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 "" > > thanks for your help, > peter -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
