Re: [Qemu-devel] [Bug 1236809] [NEW] qemu-system-x86_64 takes 100% CPU

[Stefan Hajnoczi]

On Tue, Oct 08, 2013 at 11:51:19AM -0000, chenlidong wrote:
> address@hidden:~/develop/qemu> ps -ef | grep qemu
> root     19030     1 14 19:00 ?        00:04:24 
> /usr/local/bin/qemu-system-x86_64 -name rhel6 -S -M pc-i440fx-1.6 -m 2048 
> -smp 1,sockets=1,cores=1,threads=1 -uuid 1925a96a-54b9-3c4a-dda0-6b42fdd0af2c 
> -no-user-config -nodefaults -chardev 
> socket,id=charmonitor,path=/var/lib/libvirt/qemu/rhel6.monitor,server,nowait 
> -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown 
> -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive 
> file=/var/lib/libvirt/images/rhel6.img,if=none,id=drive-ide0-0-0,format=raw,cache=directsync
>  -device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=2 
> -drive if=none,id=drive-ide0-1-0,readonly=on,format=raw -device 
> ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0,bootindex=1 -netdev 
> tap,fd=21,id=hostnet0 -device 
> rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:b3:b8:53,bus=pci.0,addr=0x3 
> -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 
> -device usb-tablet,id=input0 -vnc 127.0.0.1:0 -vga cirrus -device 
> intel-hda,id=sound0,bus=pci.0,addr=0x4 -device 
> hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -device 
> virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5
> 
> i used perf top, the result is below:
> Samples: 57K of event 'cycles', Event count (approx.): 26336443124            
>                                                                               
>                                  
>  15.38%  perf-22465.map                   [.] 0x00007f143b99c9c6
>   5.90%  qemu-system-x86_64               [.] phys_page_find
>   4.48%  qemu-system-x86_64               [.] address_space_translate_internal
>   3.30%  qemu-system-x86_64               [.] compute_all_subw
>   3.15%  qemu-system-x86_64               [.] check_regs
>   2.56%  qemu-system-x86_64               [.] tb_find_fast
>   2.34%  qemu-system-x86_64               [.] tb_find_slow

KVM is disabled - you are not using hardware virtualization extensions.
Add -enable-kvm to the command-line or make sure libvirt is using "kvm"
mode.

Stefan