Discussion:
[Qemu-discuss] High CPU in idle Windows guest
Terry Glanfield
2015-05-09 22:52:30 UTC
Permalink
Hi,

I'm running a freshly installed Windows 7 domU on an up-to-date Debian
jessie machine running Xen 4.4.1-9. When the Windows machine is idle,
I'm seeing upwards of 10% CPU usage from the qemu-system-i386 instance.
Other Linux and FreeBSD machines register negligable CPU usage (<0.5%).
The server is an HP Proliant DL360 G7.

PV drivers don't seem to make any difference.

Data from perf attacthed to the process might give the best clues.

Any information as to why this processes is comsuming so much CPU would
be much appreciated.

Regards,
Terry.

# uname -a
Linux xen 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt9-3~deb8u1 (2015-04-24) x86_64 GNU/Linux

# lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description: Debian GNU/Linux 8.0 (jessie)
Release: 8.0
Codename: jessie

# qemu-system-i386 --version
QEMU emulator version 2.1.2 (Debian 1:2.1+dfsg-11), Copyright (c) 2003-2008 Fabrice Bellard

# cat win7.cfg
name = 'win7'
vcpus = '1'
memory = '4096'
builder = 'hvm'
disk = [ '/vms/xen/domains/desk_win7/disk1.img,qcow2,hda,rw',
'/vms/xen/domains/desk_win7/disk2.img,qcow2,hdb,rw' ]
vfb = [ 'vnc=1,vnclisten="0.0.0.0",sdl=0' ]
vif = [ 'mac=00:16:3E:FB:FC:39,bridge=xenbr0' ]
serial = 'pty'
vnc = 1
vnclisten = '0.0.0.0'
sdl = 0
usbdevice = 'mouse'
audio = 1
soundhw = 'sb16,es1370'
on_poweroff = 'destroy'
on_reboot = 'restart'
on_crash = 'restart'

# /usr/bin/qemu-system-i386 -nodefaults -name desk_win7 -boot order=cda -usb -usbdevice mouse -device rtl8139,id=nic0,netdev=net0,mac=00:16:3e:fb:fc:39 -netdev type=tap,id=net0,ifname=vif12.0-emu,script=no,downscript=no -m 4088 -drive file=/vms/xen/domains/desk_win7/disk1.img,if=ide,index=0,media=disk,format=qcow2,cache=writeback -drive file=/vms/xen/domains/desk_win7/disk2.img,if=ide,index=1,media=disk,format=qcow2,cache=writeback -vnc 0.0.0.0:0,to=99 -display none -device cirrus-vga -global vga.vram_size_mb=8

# top
Tasks: 134 total, 1 running, 133 sleeping, 0 stopped, 0 zombie
%Cpu(s): 16.6 us, 5.5 sy, 0.0 ni, 0.0 id, 77.9 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 354420 total, 348884 used, 5536 free, 184 buffers
KiB Swap: 17575932 total, 2642868 used, 14933064 free. 4132 cached Mem

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
12297 root 20 0 6683864 192944 1140 S 20.6 54.4 2:25.51 qemu-syste+

# xen dmesg
(XEN) Xen version 4.4.1 (Debian 4.4.1-9) (***@debian.org) (gcc (Debian 4.9.2-10) 4.9.2) debug=n Mon Apr 6 18:24:28 UTC 2015
(XEN) Bootloader: GRUB 2.02~beta2-22
(XEN) Command line: placeholder dom0_mem=512M dom0_max_vcpus=1 dom0_vcpus_pin radeon.modeset=0 iommu=no-intremap
(XEN) Video information:
(XEN) VGA is text mode 80x25, font 8x16
(XEN) VBE/DDC methods: none; EDID transfer time: 2 seconds
(XEN) EDID info not retrieved because no DDC retrieval method detected
(XEN) Disc information:
(XEN) Found 1 MBR signatures
(XEN) Found 1 EDD information structures
(XEN) Xen-e820 RAM map:
(XEN) 0000000000000000 - 000000000009f400 (usable)
(XEN) 000000000009f400 - 00000000000a0000 (reserved)
(XEN) 00000000000f0000 - 0000000000100000 (reserved)
(XEN) 0000000000100000 - 00000000cf62f000 (usable)
XEN) 00000000cf62f000 - 00000000cf63c000 (ACPI data)
(XEN) 00000000cf63c000 - 00000000cf63d000 (usable)
(XEN) 00000000cf63d000 - 00000000d4000000 (reserved)
(XEN) 00000000fec00000 - 00000000fee10000 (reserved)
(XEN) 00000000ff800000 - 0000000100000000 (reserved)
(XEN) 0000000100000000 - 00000004affff000 (usable)
(XEN) ACPI: RSDP 000F4F00, 0024 (r2 HP )
(XEN) ACPI: XSDT CF630140, 00B4 (r1 HP ProLiant 2 162E)
(XEN) ACPI: FACP CF630240, 00F4 (r3 HP ProLiant 2 162E)
(XEN) ACPI: DSDT CF630340, 20BD (r1 HP DSDT 1 INTL 20030228)
(XEN) ACPI: FACS CF62F100, 0040
(XEN) ACPI: SPCR CF62F140, 0050 (r1 HP SPCRRBSU 1 162E)
(XEN) ACPI: MCFG CF62F1C0, 003C (r1 HP ProLiant 1 0)
(XEN) ACPI: HPET CF62F200, 0038 (r1 HP ProLiant 2 162E)
(XEN) ACPI: FFFF CF62F240, 0064 (r2 HP ProLiant 2 162E)
(XEN) ACPI: SPMI CF62F2C0, 0040 (r5 HP ProLiant 1 162E)
(XEN) ACPI: ERST CF62F300, 01D0 (r1 HP ProLiant 1 162E)
(XEN) ACPI: APIC CF62F500, 015E (r1 HP ProLiant 2 0)
(XEN) ACPI: SRAT CF62F680, 0570 (r1 HP Proliant 1 162E)
(XEN) ACPI: FFFF CF62FC00, 0176 (r1 HP ProLiant 1 162E)
(XEN) ACPI: BERT CF62FD80, 0030 (r1 HP ProLiant 1 162E)
(XEN) ACPI: HEST CF62FDC0, 00BC (r1 HP ProLiant 1 162E)
(XEN) ACPI: DMAR CF62FE80, 0150 (r1 HP ProLiant 1 162E)
(XEN) ACPI: SSDT CF632400, 0125 (r3 HP CRSPCI0 2 HP 1)
(XEN) ACPI: SSDT CF632540, 01CF (r3 HP riser1a 2 INTL 20061109)
(XEN) ACPI: SSDT CF632740, 03BB (r1 HP pcc 1 INTL 20090625)
(XEN) ACPI: SSDT CF632B00, 0377 (r1 HP pmab 1 INTL 20090625)
(XEN) ACPI: SSDT CF632E80, 2094 (r1 INTEL PPM RCM 1 INTL 20061109)
(XEN) System RAM: 18421MB (18863928kB)
(XEN) Domain heap initialised
(XEN) Processor #0 6:12 APIC version 21
(XEN) Processor #16 6:12 APIC version 21
(XEN) Processor #4 6:12 APIC version 21
(XEN) Processor #20 6:12 APIC version 21
(XEN) Processor #2 6:12 APIC version 21
(XEN) Processor #18 6:12 APIC version 21
(XEN) Processor #1 6:12 APIC version 21
(XEN) Processor #17 6:12 APIC version 21
(XEN) Processor #5 6:12 APIC version 21
(XEN) Processor #21 6:12 APIC version 21
(XEN) Processor #3 6:12 APIC version 21
(XEN) Processor #19 6:12 APIC version 21
(XEN) IOAPIC[0]: apic_id 8, version 32, address 0xfec00000, GSI 0-23
(XEN) IOAPIC[1]: apic_id 0, version 32, address 0xfec80000, GSI 24-47
(XEN) Enabling APIC mode: Phys. Using 2 I/O APICs
(XEN) Failed to get Error Log Address Range.
(XEN) Using scheduler: SMP Credit Scheduler (credit)
(XEN) Detected 2533.485 MHz processor.
(XEN) Initing memory sharing.
(XEN) Intel VT-d iommu 0 supported page sizes: 4kB.
(XEN) Intel VT-d Snoop Control not enabled.
(XEN) Intel VT-d Dom0 DMA Passthrough not enabled.
(XEN) Intel VT-d Queued Invalidation enabled.
(XEN) Intel VT-d Interrupt Remapping not enabled.
(XEN) Intel VT-d Shared EPT tables not enabled.
(XEN) I/O virtualisation enabled
(XEN) - Dom0 mode: Relaxed
(XEN) Interrupt remapping disabled
(XEN) Enabled directed EOI with ioapic_ack_old on!
(XEN) ENABLING IO-APIC IRQs
(XEN) -> Using old ACK method
(XEN) Platform timer is 14.318MHz HPET
(XEN) Allocated console ring of 32 KiB.
(XEN) VMX: Supported advanced features:
(XEN) - APIC MMIO access virtualisation
(XEN) - APIC TPR shadow
(XEN) - Extended Page Tables (EPT)
(XEN) - Virtual-Processor Identifiers (VPID)
(XEN) - Virtual NMI
(XEN) - MSR direct-access bitmap
(XEN) - Unrestricted Guest
(XEN) HVM: ASIDs enabled.
(XEN) HVM: VMX enabled
(XEN) HVM: Hardware Assisted Paging (HAP) detected
(XEN) HVM: HAP page sizes: 4kB, 2MB, 1GB
(XEN) Brought up 12 CPUs
(XEN) *** LOADING DOMAIN 0 ***
(XEN) Xen kernel: 64-bit, lsb, compat32
(XEN) Dom0 kernel: 64-bit, PAE, lsb, paddr 0x1000000 -> 0x1f18000
(XEN) PHYSICAL MEMORY ARRANGEMENT:
(XEN) Dom0 alloc.: 000000049c000000->00000004a0000000 (110661 pages to be allocated)
(XEN) Init. ramdisk: 00000004aee45000->00000004afdff7d5
(XEN) VIRTUAL MEMORY ARRANGEMENT:
(XEN) Loaded kernel: ffffffff81000000->ffffffff81f18000
(XEN) Init. ramdisk: ffffffff81f18000->ffffffff82ed27d5
(XEN) Phys-Mach map: ffffffff82ed3000->ffffffff82fd3000
(XEN) Start info: ffffffff82fd3000->ffffffff82fd34b4
(XEN) Page tables: ffffffff82fd4000->ffffffff82ff1000
(XEN) Boot stack: ffffffff82ff1000->ffffffff82ff2000
(XEN) TOTAL: ffffffff80000000->ffffffff83400000
(XEN) ENTRY ADDRESS: ffffffff819021f0
(XEN) Dom0 has maximum 1 VCPUs
(XEN) Scrubbing Free RAM: .................................................................................................................................................................................done.
(XEN) Initial low memory virq threshold set at 0x4000 pages.
(XEN) Std. Loglevel: Errors and warnings
(XEN) Guest Loglevel: Nothing (Rate-limited: Errors and warnings)
(XEN) Xen is relinquishing VGA console.
(XEN) *** Serial input -> DOM0 (type 'CTRL-a' three times to switch input to Xen)
(XEN) Freed 284kB init memory.

# perf report
# To display the perf.data header info, please use --header/--header-only options.
#
# Samples: 6K of event 'cpu-clock'
# Event count (approx.): 1744250000
#
# Overhead Command Shared Object Symbol
# ........ ............... ....................... ....................................
#
8.69% qemu-system-i38 [kernel.kallsyms] [k] xen_hypercall_xen_version
2.29% qemu-system-i38 qemu-system-i386 [.] 0x00000000000acac8
2.01% qemu-system-i38 qemu-system-i386 [.] 0x00000000000acad9
1.53% qemu-system-i38 qemu-system-i386 [.] 0x00000000000ac978
1.33% qemu-system-i38 qemu-system-i386 [.] 0x00000000000ac989
1.02% qemu-system-i38 qemu-system-i386 [.] 0x00000000000acaa4
0.93% qemu-system-i38 libc-2.19.so [.] memset
0.70% qemu-system-i38 qemu-system-i386 [.] 0x00000000000e2814
0.69% qemu-system-i38 qemu-system-i386 [.] 0x00000000000e37f4
0.67% qemu-system-i38 qemu-system-i386 [.] 0x00000000000aca40
0.66% qemu-system-i38 qemu-system-i386 [.] 0x00000000000acadf
0.60% qemu-system-i38 qemu-system-i386 [.] 0x00000000000acad7
0.59% qemu-system-i38 [vdso] [.] __vdso_clock_gettime
0.59% qemu-system-i38 qemu-system-i386 [.] 0x0000000000342b88
0.57% qemu-system-i38 [vdso] [.] __vdso_gettimeofday
0.52% qemu-system-i38 [kernel.kallsyms] [k] pvclock_clocksource_read
0.49% qemu-system-i38 qemu-system-i386 [.] 0x00000000000a9e45
0.46% qemu-system-i38 [kernel.kallsyms] [k] do_sys_poll
0.37% qemu-system-i38 [kernel.kallsyms] [k] hrtimer_init
0.36% qemu-system-i38 [kernel.kallsyms] [k] __fget
0.34% qemu-system-i38 [kernel.kallsyms] [k] ktime_get_ts
Dave Gosselin
2015-05-10 00:53:38 UTC
Permalink
Try supplying the -enable-kvm option to your qemu arguments. If it doesn't work then the support may not be compiled in to qemu or the driver may not be loaded into the kernel. Let me know.
Dave Gosselin

Sent from my iPhone
Post by Terry Glanfield
Hi,
I'm running a freshly installed Windows 7 domU on an up-to-date Debian
jessie machine running Xen 4.4.1-9. When the Windows machine is idle,
I'm seeing upwards of 10% CPU usage from the qemu-system-i386 instance.
Other Linux and FreeBSD machines register negligable CPU usage (<0.5%).
The server is an HP Proliant DL360 G7.
PV drivers don't seem to make any difference.
Data from perf attacthed to the process might give the best clues.
Any information as to why this processes is comsuming so much CPU would
be much appreciated.
Regards,
Terry.
# uname -a
Linux xen 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt9-3~deb8u1 (2015-04-24) x86_64 GNU/Linux
# lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description: Debian GNU/Linux 8.0 (jessie)
Release: 8.0
Codename: jessie
# qemu-system-i386 --version
QEMU emulator version 2.1.2 (Debian 1:2.1+dfsg-11), Copyright (c) 2003-2008 Fabrice Bellard
# cat win7.cfg
name = 'win7'
vcpus = '1'
memory = '4096'
builder = 'hvm'
disk = [ '/vms/xen/domains/desk_win7/disk1.img,qcow2,hda,rw',
'/vms/xen/domains/desk_win7/disk2.img,qcow2,hdb,rw' ]
vfb = [ 'vnc=1,vnclisten="0.0.0.0",sdl=0' ]
vif = [ 'mac=00:16:3E:FB:FC:39,bridge=xenbr0' ]
serial = 'pty'
vnc = 1
vnclisten = '0.0.0.0'
sdl = 0
usbdevice = 'mouse'
audio = 1
soundhw = 'sb16,es1370'
on_poweroff = 'destroy'
on_reboot = 'restart'
on_crash = 'restart'
# /usr/bin/qemu-system-i386 -nodefaults -name desk_win7 -boot order=cda -usb -usbdevice mouse -device rtl8139,id=nic0,netdev=net0,mac=00:16:3e:fb:fc:39 -netdev type=tap,id=net0,ifname=vif12.0-emu,script=no,downscript=no -m 4088 -drive file=/vms/xen/domains/desk_win7/disk1.img,if=ide,index=0,media=disk,format=qcow2,cache=writeback -drive file=/vms/xen/domains/desk_win7/disk2.img,if=ide,index=1,media=disk,format=qcow2,cache=writeback -vnc 0.0.0.0:0,to=99 -display none -device cirrus-vga -global vga.vram_size_mb=8
# top
Tasks: 134 total, 1 running, 133 sleeping, 0 stopped, 0 zombie
%Cpu(s): 16.6 us, 5.5 sy, 0.0 ni, 0.0 id, 77.9 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 354420 total, 348884 used, 5536 free, 184 buffers
KiB Swap: 17575932 total, 2642868 used, 14933064 free. 4132 cached Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
12297 root 20 0 6683864 192944 1140 S 20.6 54.4 2:25.51 qemu-syste+
# xen dmesg
(XEN) Bootloader: GRUB 2.02~beta2-22
(XEN) Command line: placeholder dom0_mem=512M dom0_max_vcpus=1 dom0_vcpus_pin radeon.modeset=0 iommu=no-intremap
(XEN) VGA is text mode 80x25, font 8x16
(XEN) VBE/DDC methods: none; EDID transfer time: 2 seconds
(XEN) EDID info not retrieved because no DDC retrieval method detected
(XEN) Found 1 MBR signatures
(XEN) Found 1 EDD information structures
(XEN) 0000000000000000 - 000000000009f400 (usable)
(XEN) 000000000009f400 - 00000000000a0000 (reserved)
(XEN) 00000000000f0000 - 0000000000100000 (reserved)
(XEN) 0000000000100000 - 00000000cf62f000 (usable)
XEN) 00000000cf62f000 - 00000000cf63c000 (ACPI data)
(XEN) 00000000cf63c000 - 00000000cf63d000 (usable)
(XEN) 00000000cf63d000 - 00000000d4000000 (reserved)
(XEN) 00000000fec00000 - 00000000fee10000 (reserved)
(XEN) 00000000ff800000 - 0000000100000000 (reserved)
(XEN) 0000000100000000 - 00000004affff000 (usable)
(XEN) ACPI: RSDP 000F4F00, 0024 (r2 HP )
(XEN) ACPI: XSDT CF630140, 00B4 (r1 HP ProLiant 2 162E)
(XEN) ACPI: FACP CF630240, 00F4 (r3 HP ProLiant 2 162E)
(XEN) ACPI: DSDT CF630340, 20BD (r1 HP DSDT 1 INTL 20030228)
(XEN) ACPI: FACS CF62F100, 0040
(XEN) ACPI: SPCR CF62F140, 0050 (r1 HP SPCRRBSU 1 162E)
(XEN) ACPI: MCFG CF62F1C0, 003C (r1 HP ProLiant 1 0)
(XEN) ACPI: HPET CF62F200, 0038 (r1 HP ProLiant 2 162E)
(XEN) ACPI: FFFF CF62F240, 0064 (r2 HP ProLiant 2 162E)
(XEN) ACPI: SPMI CF62F2C0, 0040 (r5 HP ProLiant 1 162E)
(XEN) ACPI: ERST CF62F300, 01D0 (r1 HP ProLiant 1 162E)
(XEN) ACPI: APIC CF62F500, 015E (r1 HP ProLiant 2 0)
(XEN) ACPI: SRAT CF62F680, 0570 (r1 HP Proliant 1 162E)
(XEN) ACPI: FFFF CF62FC00, 0176 (r1 HP ProLiant 1 162E)
(XEN) ACPI: BERT CF62FD80, 0030 (r1 HP ProLiant 1 162E)
(XEN) ACPI: HEST CF62FDC0, 00BC (r1 HP ProLiant 1 162E)
(XEN) ACPI: DMAR CF62FE80, 0150 (r1 HP ProLiant 1 162E)
(XEN) ACPI: SSDT CF632400, 0125 (r3 HP CRSPCI0 2 HP 1)
(XEN) ACPI: SSDT CF632540, 01CF (r3 HP riser1a 2 INTL 20061109)
(XEN) ACPI: SSDT CF632740, 03BB (r1 HP pcc 1 INTL 20090625)
(XEN) ACPI: SSDT CF632B00, 0377 (r1 HP pmab 1 INTL 20090625)
(XEN) ACPI: SSDT CF632E80, 2094 (r1 INTEL PPM RCM 1 INTL 20061109)
(XEN) System RAM: 18421MB (18863928kB)
(XEN) Domain heap initialised
(XEN) Processor #0 6:12 APIC version 21
(XEN) Processor #16 6:12 APIC version 21
(XEN) Processor #4 6:12 APIC version 21
(XEN) Processor #20 6:12 APIC version 21
(XEN) Processor #2 6:12 APIC version 21
(XEN) Processor #18 6:12 APIC version 21
(XEN) Processor #1 6:12 APIC version 21
(XEN) Processor #17 6:12 APIC version 21
(XEN) Processor #5 6:12 APIC version 21
(XEN) Processor #21 6:12 APIC version 21
(XEN) Processor #3 6:12 APIC version 21
(XEN) Processor #19 6:12 APIC version 21
(XEN) IOAPIC[0]: apic_id 8, version 32, address 0xfec00000, GSI 0-23
(XEN) IOAPIC[1]: apic_id 0, version 32, address 0xfec80000, GSI 24-47
(XEN) Enabling APIC mode: Phys. Using 2 I/O APICs
(XEN) Failed to get Error Log Address Range.
(XEN) Using scheduler: SMP Credit Scheduler (credit)
(XEN) Detected 2533.485 MHz processor.
(XEN) Initing memory sharing.
(XEN) Intel VT-d iommu 0 supported page sizes: 4kB.
(XEN) Intel VT-d Snoop Control not enabled.
(XEN) Intel VT-d Dom0 DMA Passthrough not enabled.
(XEN) Intel VT-d Queued Invalidation enabled.
(XEN) Intel VT-d Interrupt Remapping not enabled.
(XEN) Intel VT-d Shared EPT tables not enabled.
(XEN) I/O virtualisation enabled
(XEN) - Dom0 mode: Relaxed
(XEN) Interrupt remapping disabled
(XEN) Enabled directed EOI with ioapic_ack_old on!
(XEN) ENABLING IO-APIC IRQs
(XEN) -> Using old ACK method
(XEN) Platform timer is 14.318MHz HPET
(XEN) Allocated console ring of 32 KiB.
(XEN) - APIC MMIO access virtualisation
(XEN) - APIC TPR shadow
(XEN) - Extended Page Tables (EPT)
(XEN) - Virtual-Processor Identifiers (VPID)
(XEN) - Virtual NMI
(XEN) - MSR direct-access bitmap
(XEN) - Unrestricted Guest
(XEN) HVM: ASIDs enabled.
(XEN) HVM: VMX enabled
(XEN) HVM: Hardware Assisted Paging (HAP) detected
(XEN) HVM: HAP page sizes: 4kB, 2MB, 1GB
(XEN) Brought up 12 CPUs
(XEN) *** LOADING DOMAIN 0 ***
(XEN) Xen kernel: 64-bit, lsb, compat32
(XEN) Dom0 kernel: 64-bit, PAE, lsb, paddr 0x1000000 -> 0x1f18000
(XEN) Dom0 alloc.: 000000049c000000->00000004a0000000 (110661 pages to be allocated)
(XEN) Init. ramdisk: 00000004aee45000->00000004afdff7d5
(XEN) Loaded kernel: ffffffff81000000->ffffffff81f18000
(XEN) Init. ramdisk: ffffffff81f18000->ffffffff82ed27d5
(XEN) Phys-Mach map: ffffffff82ed3000->ffffffff82fd3000
(XEN) Start info: ffffffff82fd3000->ffffffff82fd34b4
(XEN) Page tables: ffffffff82fd4000->ffffffff82ff1000
(XEN) Boot stack: ffffffff82ff1000->ffffffff82ff2000
(XEN) TOTAL: ffffffff80000000->ffffffff83400000
(XEN) ENTRY ADDRESS: ffffffff819021f0
(XEN) Dom0 has maximum 1 VCPUs
(XEN) Scrubbing Free RAM: .................................................................................................................................................................................done.
(XEN) Initial low memory virq threshold set at 0x4000 pages.
(XEN) Std. Loglevel: Errors and warnings
(XEN) Guest Loglevel: Nothing (Rate-limited: Errors and warnings)
(XEN) Xen is relinquishing VGA console.
(XEN) *** Serial input -> DOM0 (type 'CTRL-a' three times to switch input to Xen)
(XEN) Freed 284kB init memory.
# perf report
# To display the perf.data header info, please use --header/--header-only options.
#
# Samples: 6K of event 'cpu-clock'
# Event count (approx.): 1744250000
#
# Overhead Command Shared Object Symbol
# ........ ............... ....................... ....................................
#
8.69% qemu-system-i38 [kernel.kallsyms] [k] xen_hypercall_xen_version
2.29% qemu-system-i38 qemu-system-i386 [.] 0x00000000000acac8
2.01% qemu-system-i38 qemu-system-i386 [.] 0x00000000000acad9
1.53% qemu-system-i38 qemu-system-i386 [.] 0x00000000000ac978
1.33% qemu-system-i38 qemu-system-i386 [.] 0x00000000000ac989
1.02% qemu-system-i38 qemu-system-i386 [.] 0x00000000000acaa4
0.93% qemu-system-i38 libc-2.19.so [.] memset
0.70% qemu-system-i38 qemu-system-i386 [.] 0x00000000000e2814
0.69% qemu-system-i38 qemu-system-i386 [.] 0x00000000000e37f4
0.67% qemu-system-i38 qemu-system-i386 [.] 0x00000000000aca40
0.66% qemu-system-i38 qemu-system-i386 [.] 0x00000000000acadf
0.60% qemu-system-i38 qemu-system-i386 [.] 0x00000000000acad7
0.59% qemu-system-i38 [vdso] [.] __vdso_clock_gettime
0.59% qemu-system-i38 qemu-system-i386 [.] 0x0000000000342b88
0.57% qemu-system-i38 [vdso] [.] __vdso_gettimeofday
0.52% qemu-system-i38 [kernel.kallsyms] [k] pvclock_clocksource_read
0.49% qemu-system-i38 qemu-system-i386 [.] 0x00000000000a9e45
0.46% qemu-system-i38 [kernel.kallsyms] [k] do_sys_poll
0.37% qemu-system-i38 [kernel.kallsyms] [k] hrtimer_init
0.36% qemu-system-i38 [kernel.kallsyms] [k] __fget
0.34% qemu-system-i38 [kernel.kallsyms] [k] ktime_get_ts
Terry Glanfield
2015-05-10 00:44:53 UTC
Permalink
Hi Dave,

With -enable-kvm I get.

Could not access KVM kernel module: No such file or directory
failed to initialize KVM: No such file or directory

Where to next? I'm willing to help diagnose it in whatever way I can.

Regards,
Terry.
Post by Dave Gosselin
Try supplying the -enable-kvm option to your qemu arguments. If it
doesn't work then the support may not be compiled in to qemu or the
driver may not be loaded into the kernel. Let me know.
Dave Gosselin
Sent from my iPhone
Post by Terry Glanfield
Hi,
I'm running a freshly installed Windows 7 domU on an up-to-date Debian
jessie machine running Xen 4.4.1-9. When the Windows machine is idle,
I'm seeing upwards of 10% CPU usage from the qemu-system-i386 instance.
Other Linux and FreeBSD machines register negligable CPU usage (<0.5%).
The server is an HP Proliant DL360 G7.
PV drivers don't seem to make any difference.
Data from perf attacthed to the process might give the best clues.
Any information as to why this processes is comsuming so much CPU would
be much appreciated.
Regards,
Terry.
Dave Gosselin
2015-05-10 13:48:58 UTC
Permalink
Hi Terry,

It appears that the kernel driver hasn't been started. You can do this
manually, before starting qemu, by running this as the root user:
modprobe kvm

You can confirm that the modprobe command started via the lsmod
command: lsmod | grep -i kvm
If you see any entries, it's loaded; if the command returns with
nothing, then it did not load.

Afterwards, you can run qemu but you may have to run it as root for it
to take advantage of the KVM module you just started.

Dave
Post by Terry Glanfield
Hi Dave,
With -enable-kvm I get.
Could not access KVM kernel module: No such file or directory
failed to initialize KVM: No such file or directory
Where to next? I'm willing to help diagnose it in whatever way I can.
Regards,
Terry.
Post by Dave Gosselin
Try supplying the -enable-kvm option to your qemu arguments. If it
doesn't work then the support may not be compiled in to qemu or the
driver may not be loaded into the kernel. Let me know.
Dave Gosselin
Sent from my iPhone
Post by Terry Glanfield
Hi,
I'm running a freshly installed Windows 7 domU on an up-to-date Debian
jessie machine running Xen 4.4.1-9. When the Windows machine is idle,
I'm seeing upwards of 10% CPU usage from the qemu-system-i386 instance.
Other Linux and FreeBSD machines register negligable CPU usage (<0.5%).
The server is an HP Proliant DL360 G7.
PV drivers don't seem to make any difference.
Data from perf attacthed to the process might give the best clues.
Any information as to why this processes is comsuming so much CPU would
be much appreciated.
Regards,
Terry.
Terry Glanfield
2015-05-10 15:14:43 UTC
Permalink
Hi Dave,

You do know that I'm running a Xen hypervisor and not KVM?

I'm not wedded to Xen and would consider using KVM if it's more likely
to solve my problem, but it would be good to get the Xen solution
working properly.

Regards,
Terry.
Post by Dave Gosselin
Hi Terry,
It appears that the kernel driver hasn't been started. You can do
modprobe kvm
You can confirm that the modprobe command started via the lsmod
command: lsmod | grep -i kvm
If you see any entries, it's loaded; if the command returns with
nothing, then it did not load.
Afterwards, you can run qemu but you may have to run it as root for it
to take advantage of the KVM module you just started.
Dave
Post by Terry Glanfield
Hi Dave,
With -enable-kvm I get.
Could not access KVM kernel module: No such file or directory
failed to initialize KVM: No such file or directory
Where to next? I'm willing to help diagnose it in whatever way I can.
Regards,
Terry.
Post by Dave Gosselin
Try supplying the -enable-kvm option to your qemu arguments. If it
doesn't work then the support may not be compiled in to qemu or the
driver may not be loaded into the kernel. Let me know.
Dave Gosselin
Sent from my iPhone
Post by Terry Glanfield
Hi,
I'm running a freshly installed Windows 7 domU on an up-to-date Debian
jessie machine running Xen 4.4.1-9. When the Windows machine is idle,
I'm seeing upwards of 10% CPU usage from the qemu-system-i386 instance.
Other Linux and FreeBSD machines register negligable CPU usage (<0.5%).
The server is an HP Proliant DL360 G7.
PV drivers don't seem to make any difference.
Data from perf attacthed to the process might give the best clues.
Any information as to why this processes is comsuming so much CPU would
be much appreciated.
Regards,
Terry.
Jakob Bohm
2015-05-12 11:55:11 UTC
Permalink
(top posting to keep thread consistent)

Then you should remember to pass the qemu options to
start the VM as a XEN DomU, not as a software VM inside
your current (Dom0) VM.

I think (from reading qemu --help) that you may need
to do that via something called xend, there is probably
a manual somewhere.
Post by Terry Glanfield
Hi Dave,
You do know that I'm running a Xen hypervisor and not KVM?
I'm not wedded to Xen and would consider using KVM if it's more likely
to solve my problem, but it would be good to get the Xen solution
working properly.
Regards,
Terry.
Post by Dave Gosselin
Hi Terry,
It appears that the kernel driver hasn't been started. You can do
modprobe kvm
You can confirm that the modprobe command started via the lsmod
command: lsmod | grep -i kvm
If you see any entries, it's loaded; if the command returns with
nothing, then it did not load.
Afterwards, you can run qemu but you may have to run it as root for it
to take advantage of the KVM module you just started.
Dave
Post by Terry Glanfield
Hi Dave,
With -enable-kvm I get.
Could not access KVM kernel module: No such file or directory
failed to initialize KVM: No such file or directory
Where to next? I'm willing to help diagnose it in whatever way I can.
Regards,
Terry.
Post by Dave Gosselin
Try supplying the -enable-kvm option to your qemu arguments. If it
doesn't work then the support may not be compiled in to qemu or the
driver may not be loaded into the kernel. Let me know.
Dave Gosselin
Sent from my iPhone
Post by Terry Glanfield
Hi,
I'm running a freshly installed Windows 7 domU on an up-to-date Debian
jessie machine running Xen 4.4.1-9. When the Windows machine is idle,
I'm seeing upwards of 10% CPU usage from the qemu-system-i386 instance.
Other Linux and FreeBSD machines register negligable CPU usage (<0.5%).
The server is an HP Proliant DL360 G7.
PV drivers don't seem to make any difference.
Data from perf attacthed to the process might give the best clues.
Any information as to why this processes is comsuming so much CPU would
be much appreciated.
Regards,
Terry.
Enjoy

Jakob
--
Jakob Bohm, CIO, Partner, WiseMo A/S. https://www.wisemo.com
Transformervej 29, 2860 Søborg, Denmark. Direct +45 31 13 16 10
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WiseMo - Remote Service Management for PCs, Phones and Embedded
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