High interrupt usage on IO

["Brad Pitney" <pitney.brad%googlemail.com@localhost>]

Hi,

I am experiencing high interrupt usage on disk read/writes whether it
is under Dom0 or DomU, which results in a rather paltry 2MB/ps writing
when doing a say:
$ dd if=/dev/zero of=tempimg bs=1m count=555
for example.

the discs are IDE (not sata or scsi) I've tried new cables too. Then
again I experience the same thing if I use a flash drive or an IDE
drive connected to USB.

I don't remember seeing this problem before when I was exploring
NetBSD/Xen as a FreeBSD/Jail replacement, then again that was on i386
and not AMD64.

NetBSD frazzle 4.99.54 NetBSD 4.99.54 (MY_XEN3_DOM0) #2: Mon Mar  3
13:26:54 GMT 2008
root@frazzle:/usr/obj/sys/arch/amd64/compile/MY_XEN3_DOM0 amd64

it causes problems on boot (I think) as a most domains end up restarting:

here is some /var/log/message output:
Mar 12 03:21:05 frazzle /netbsd: Copyright (c) 1996, 1997, 1998, 1999,
2000, 2001, 2002, 2003, 2004, 2005,
Mar 12 03:21:05 frazzle /netbsd: 2006, 2007, 2008
Mar 12 03:21:05 frazzle /netbsd: The NetBSD Foundation, Inc.  All
rights reserved.
Mar 12 03:21:05 frazzle /netbsd: Copyright (c) 1982, 1986, 1989, 1991, 1993
Mar 12 03:21:05 frazzle /netbsd: The Regents of the University of
California.  All rights reserved.
Mar 12 03:21:05 frazzle /netbsd:
Mar 12 03:21:05 frazzle /netbsd: NetBSD 4.99.54 (MY_XEN3_DOM0) #2: Mon
Mar  3 13:26:54 GMT 2008
Mar 12 03:21:05 frazzle /netbsd:
root@frazzle:/usr/obj/sys/arch/amd64/compile/MY_XEN3_DOM0
Mar 12 03:21:05 frazzle /netbsd: total memory = 128 MB
Mar 12 03:21:05 frazzle /netbsd: avail memory = 116 MB
Mar 12 03:21:05 frazzle /netbsd: timecounter: Timecounters tick every
10.000 msec
Mar 12 03:21:05 frazzle /netbsd: SMBIOS rev. 2.2 @ 0xf0800 (33 entries)
Mar 12 03:21:05 frazzle /netbsd: mainbus0 (root)
Mar 12 03:21:05 frazzle /netbsd: cpu0 at mainbus0 apid 0: (boot processor)
Mar 12 03:21:05 frazzle /netbsd: ioapic0 at mainbus0 apid 2: pa
0xfec00000, version 14, 24 pins
Mar 12 03:21:05 frazzle /netbsd: hypervisor0 at mainbus0
Mar 12 03:21:05 frazzle /netbsd: vcpu0 at hypervisor0: (uniprocessor)
Mar 12 03:21:05 frazzle /netbsd: vcpu0: AMD Sempron(tm) Processor
3000+, 1799.49 MHz
Mar 12 03:21:05 frazzle /netbsd: vcpu0: features:
e7dbfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR>
Mar 12 03:21:05 frazzle /netbsd: vcpu0: features:
e7dbfbff<PGE,MCA,CMOV,PAT,PSE36,MPC,NOX,MMXX,MMX>
Mar 12 03:21:05 frazzle /netbsd: vcpu0: features:
e7dbfbff<FXSR,SSE,SSE2,LONG,3DNOW2,3DNOW>
Mar 12 03:21:05 frazzle /netbsd: vcpu0: features2: 1<SSE3>
Mar 12 03:21:05 frazzle /netbsd: vcpu0: I-cache 64 KB 64B/line 2-way,
D-cache 64 KB 64B/line 2-way
Mar 12 03:21:05 frazzle /netbsd: vcpu0: L2 cache 128 KB 64B/line 16-way
Mar 12 03:21:05 frazzle /netbsd: vcpu0: ITLB 32 4 KB entries fully
associative, 8 4 MB entries fully associative
Mar 12 03:21:05 frazzle /netbsd: vcpu0: DTLB 32 4 KB entries fully
associative, 8 4 MB entries fully associative
Mar 12 03:21:05 frazzle /netbsd: vcpu0: Initial APIC ID 0
Mar 12 03:21:05 frazzle /netbsd: vcpu0: 8 page colors
Mar 12 03:21:05 frazzle /netbsd: debug virtual interrupt using event channel 1
Mar 12 03:21:05 frazzle /netbsd: xenbus0 at hypervisor0: Xen Virtual
Bus Interface
Mar 12 03:21:05 frazzle /netbsd: xencons0 at hypervisor0: Xen Virtual
Console Driver
Mar 12 03:21:05 frazzle /netbsd: acpi0 at hypervisor0: Advanced
Configuration and Power Interface
Mar 12 03:21:05 frazzle /netbsd: acpi0: using Intel ACPI CA subsystem
version 20070320
Mar 12 03:21:05 frazzle /netbsd: acpi0: X/RSDT: OemId <AWARD
,AWRDACPI,42302e31>, AslId <AWRD,00000000>
Mar 12 03:21:05 frazzle /netbsd: mpacpi: could not get bus number,
assuming bus 0
Mar 12 03:21:05 frazzle /netbsd: acpi0: SCI interrupting at int 9
Mar 12 03:21:05 frazzle /netbsd: acpi0: fixed-feature power button present
Mar 12 03:21:05 frazzle /netbsd: timecounter: Timecounter "ACPI-Safe"
frequency 3579545 Hz quality 900
Mar 12 03:21:05 frazzle /netbsd: ACPI-Safe 24-bit timer
Mar 12 03:21:05 frazzle /netbsd: CPU0 (ACPI Object Type 'Processor'
[0x0c]) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: acpibut0 at acpi0 (PWRB, PNP0C0C):
ACPI Power Button
Mar 12 03:21:05 frazzle /netbsd: MEM (PNP0C01) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: PCI0 (PNP0A03) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: LNKC (PNP0C0F) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: LNKD (PNP0C0F) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: LNKE (PNP0C0F) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: LNKF (PNP0C0F) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: LNKG (PNP0C0F) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: LNKH (PNP0C0F) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: SYSR (PNP0C02) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: PIC (PNP0000) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: DMA1 (PNP0200) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: TMR (PNP0100) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: RTC (PNP0B00) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: SPKR (PNP0800) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: COPR (PNP0C04) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: PS2K (PNP0303) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: FAN (PNP0C0B) at acpi0 not configured
Mar 12 03:21:05 frazzle /netbsd: acpitz0 at acpi0 (THRM): active
cooling level 0: 118.0C critical 120.0C passive 40.0C
Mar 12 03:21:05 frazzle /netbsd: pci0 at hypervisor0 bus 0: configuration mode 1
Mar 12 03:21:05 frazzle /netbsd: pci0: i/o space, memory space enabled
Mar 12 03:21:05 frazzle /netbsd: pchb0 at pci0 dev 0 function 0
Mar 12 03:21:05 frazzle /netbsd: pchb0: vendor 0x1039 product 0x0760 (rev. 0x03)
Mar 12 03:21:05 frazzle /netbsd: agp0 at pchb0: aperture at
0xe8000000, size 0x400000
Mar 12 03:21:05 frazzle /netbsd: ppb0 at pci0 dev 1 function 0: vendor
0x1039 product 0x0002 (rev. 0x00)
Mar 12 03:21:05 frazzle /netbsd: pci1 at ppb0 bus 1
Mar 12 03:21:05 frazzle /netbsd: pci1: i/o space, memory space enabled
Mar 12 03:21:05 frazzle /netbsd: vga0 at pci1 dev 0 function 0: vendor
0x1002 product 0x5159 (rev. 0x00)
Mar 12 03:21:05 frazzle /netbsd: wsdisplay0 at vga0 kbdmux 1: console
(80x25, vt100 emulation)
Mar 12 03:21:05 frazzle /netbsd: wsmux1: connecting to wsdisplay0
Mar 12 03:21:05 frazzle /netbsd: wsdisplay0: screen 1-3 added (80x25,
vt100 emulation)
Mar 12 03:21:05 frazzle /netbsd: direct rendering for vga0 unsupported
Mar 12 03:21:05 frazzle /netbsd: pcib0 at pci0 dev 2 function 0
Mar 12 03:21:05 frazzle /netbsd: pcib0: vendor 0x1039 product 0x0964 (rev. 0x36)
Mar 12 03:21:05 frazzle /netbsd: pciide0 at pci0 dev 2 function 5
Mar 12 03:21:05 frazzle /netbsd: pciide0: vendor 0x1039 product 0x5513
(rev. 0x01)
Mar 12 03:21:05 frazzle /netbsd: pciide0: bus-master DMA support
present, but unused (no driver support)
Mar 12 03:21:05 frazzle /netbsd: pciide0: primary channel wired to
compatibility mode
Mar 12 03:21:05 frazzle /netbsd: pciide0: primary channel interrupting
at ioapic0 pin 14, event channel 3
Mar 12 03:21:05 frazzle /netbsd: atabus0 at pciide0 channel 0
Mar 12 03:21:05 frazzle /netbsd: pciide0: secondary channel wired to
compatibility mode
Mar 12 03:21:05 frazzle /netbsd: pciide0: secondary channel
interrupting at ioapic0 pin 15, event channel 4
Mar 12 03:21:05 frazzle /netbsd: atabus1 at pciide0 channel 1
Mar 12 03:21:05 frazzle /netbsd: auich0 at pci0 dev 2 function 7: SiS
7012 AC-97 Audio
Mar 12 03:21:05 frazzle /netbsd: auich0: interrupting at ioapic0 pin
18, event channel 5
Mar 12 03:21:05 frazzle /netbsd: auich0: ac97: Analog Devices AD1888
codec; headphone, 20 bit DAC, no 3D stereo
Mar 12 03:21:05 frazzle /netbsd: auich0: ac97: ext id
3c7<AMAP,LDAC,SDAC,CDAC,SPDIF,DRA,VRA>
Mar 12 03:21:05 frazzle /netbsd: ohci0 at pci0 dev 3 function 0:
vendor 0x1039 product 0x7001 (rev. 0x0f)
Mar 12 03:21:05 frazzle /netbsd: ohci0: interrupting at ioapic0 pin
20, event channel 6
Mar 12 03:21:05 frazzle /netbsd: ohci0: OHCI version 1.0, legacy support
Mar 12 03:21:05 frazzle /netbsd: usb0 at ohci0: USB revision 1.0
Mar 12 03:21:05 frazzle /netbsd: uhub0 at usb0
Mar 12 03:21:05 frazzle /netbsd: uhub0: vendor 0x1039 OHCI root hub,
class 9/0, rev 1.00/1.00, addr 1
Mar 12 03:21:05 frazzle /netbsd: uhub0: 3 ports with 3 removable, self powered
Mar 12 03:21:05 frazzle /netbsd: ohci1 at pci0 dev 3 function 1:
vendor 0x1039 product 0x7001 (rev. 0x0f)
Mar 12 03:21:05 frazzle /netbsd: ohci1: interrupting at ioapic0 pin
21, event channel 7
Mar 12 03:21:05 frazzle /netbsd: ohci1: OHCI version 1.0, legacy support
Mar 12 03:21:05 frazzle /netbsd: usb1 at ohci1: USB revision 1.0
Mar 12 03:21:05 frazzle /netbsd: uhub1 at usb1
Mar 12 03:21:05 frazzle /netbsd: uhub1: vendor 0x1039 OHCI root hub,
class 9/0, rev 1.00/1.00, addr 1
Mar 12 03:21:05 frazzle /netbsd: uhub1: 3 ports with 3 removable, self powered
Mar 12 03:21:05 frazzle /netbsd: ohci2 at pci0 dev 3 function 2:
vendor 0x1039 product 0x7001 (rev. 0x0f)
Mar 12 03:21:05 frazzle /netbsd: ohci2: interrupting at ioapic0 pin
22, event channel 8
Mar 12 03:21:05 frazzle /netbsd: ohci2: OHCI version 1.0, legacy support
Mar 12 03:21:05 frazzle /netbsd: usb2 at ohci2: USB revision 1.0
Mar 12 03:21:05 frazzle /netbsd: uhub2 at usb2
Mar 12 03:21:05 frazzle /netbsd: uhub2: vendor 0x1039 OHCI root hub,
class 9/0, rev 1.00/1.00, addr 1
Mar 12 03:21:05 frazzle /netbsd: uhub2: 2 ports with 2 removable, self powered
Mar 12 03:21:05 frazzle /netbsd: ehci0 at pci0 dev 3 function 3:
vendor 0x1039 product 0x7002 (rev. 0x00)
Mar 12 03:21:05 frazzle /netbsd: ehci0: interrupting at ioapic0 pin
23, event channel 9
Mar 12 03:21:05 frazzle /netbsd: ehci0: EHCI version 1.0
Mar 12 03:21:05 frazzle /netbsd: ehci0: companion controllers, 3 ports
each: ohci0 ohci1 ohci2
Mar 12 03:21:05 frazzle /netbsd: usb3 at ehci0: USB revision 2.0
Mar 12 03:21:05 frazzle /netbsd: uhub3 at usb3
Mar 12 03:21:05 frazzle /netbsd: uhub3: vendor 0x1039 EHCI root hub,
class 9/0, rev 2.00/1.00, addr 1
Mar 12 03:21:05 frazzle /netbsd: uhub3: 8 ports with 8 removable, self powered
Mar 12 03:21:05 frazzle /netbsd: sip0 at pci0 dev 4 function 0: SiS
900 10/100 Ethernet, rev 0x91
Mar 12 03:21:05 frazzle /netbsd: sip0: interrupting at ioapic0 pin 19,
event channel 10
Mar 12 03:21:05 frazzle /netbsd: sip0: Ethernet address 00:15:58:5a:11:56
Mar 12 03:21:05 frazzle /netbsd: rlphy0 at sip0 phy 1: RTL8201L 10/100
media interface, rev. 1
Mar 12 03:21:05 frazzle /netbsd: rlphy0: 10baseT, 10baseT-FDX,
100baseTX, 100baseTX-FDX, auto
Mar 12 03:21:05 frazzle /netbsd: fxp0 at pci0 dev 9 function 0: i82550
Ethernet, rev 13
Mar 12 03:21:05 frazzle /netbsd: fxp0: interrupting at ioapic0 pin 19,
event channel 10
Mar 12 03:21:05 frazzle /netbsd: fxp0: Ethernet address 00:02:b3:b4:e1:9d
Mar 12 03:21:05 frazzle /netbsd: inphy0 at fxp0 phy 1: i82555 10/100
media interface, rev. 4
Mar 12 03:21:05 frazzle /netbsd: inphy0: 10baseT, 10baseT-FDX,
100baseTX, 100baseTX-FDX, auto
Mar 12 03:21:05 frazzle /netbsd: pchb1 at pci0 dev 24 function 0
Mar 12 03:21:05 frazzle /netbsd: pchb1: vendor 0x1022 product 0x1100 (rev. 0x00)
Mar 12 03:21:05 frazzle /netbsd: pchb2 at pci0 dev 24 function 1
Mar 12 03:21:05 frazzle /netbsd: pchb2: vendor 0x1022 product 0x1101 (rev. 0x00)
Mar 12 03:21:05 frazzle /netbsd: pchb3 at pci0 dev 24 function 2
Mar 12 03:21:05 frazzle /netbsd: pchb3: vendor 0x1022 product 0x1102 (rev. 0x00)
Mar 12 03:21:05 frazzle /netbsd: pchb4 at pci0 dev 24 function 3
Mar 12 03:21:05 frazzle /netbsd: pchb4: vendor 0x1022 product 0x1103 (rev. 0x00)
Mar 12 03:21:05 frazzle /netbsd: isa0 at pcib0
Mar 12 03:21:05 frazzle /netbsd: pckbc0 at isa0 port 0x60-0x64
Mar 12 03:21:05 frazzle /netbsd: pckbd0 at pckbc0 (kbd slot)
Mar 12 03:21:05 frazzle /netbsd: pckbc0: using irq 1 for kbd slot
Mar 12 03:21:05 frazzle /netbsd: wskbd0 at pckbd0: console keyboard,
using wsdisplay0
Mar 12 03:21:05 frazzle /netbsd: itesio0 at isa0 port 0x2e-0x2f: iTE
IT8705F Super I/O (rev 3)
Mar 12 03:21:05 frazzle /netbsd: itesio0: Hardware Monitor registers at 0x290
Mar 12 03:21:05 frazzle /netbsd: timecounter: Timecounter
"clockinterrupt" frequency 100 Hz quality 0
Mar 12 03:21:05 frazzle /netbsd: Xen clock: using event channel 12
Mar 12 03:21:05 frazzle /netbsd: timecounter: Timecounter
"xen_system_time" frequency 1000000000 Hz quality 10000
Mar 12 03:21:05 frazzle /netbsd: auich0: measured ac97 link rate at
25363 Hz, will use 48000 Hz
Mar 12 03:21:05 frazzle /netbsd: audio0 at auich0: full duplex, mmap,
independent
Mar 12 03:21:05 frazzle /netbsd: initializing IPsec... done
Mar 12 03:21:05 frazzle /netbsd: IPsec: Initialized Security
Association Processing.
Mar 12 03:21:05 frazzle /netbsd: xenbus0: using event channel 13
Mar 12 03:21:05 frazzle /netbsd: wd0 at atabus0 drive 0: <WDC WD400EB-11CPF0>
Mar 12 03:21:05 frazzle /netbsd: wd0: drive supports 16-sector PIO
transfers, LBA addressing
Mar 12 03:21:05 frazzle /netbsd: wd0: 38166 MB, 77545 cyl, 16 head, 63
sec, 512 bytes/sect x 78165360 sectors
Mar 12 03:21:05 frazzle /netbsd: wd0: drive supports PIO mode 4, DMA
mode 2, Ultra-DMA mode 5 (Ultra/100)
Mar 12 03:21:05 frazzle /netbsd: wd1 at atabus1 drive 0: <ExcelStor
Technology J360>
Mar 12 03:21:05 frazzle /netbsd: wd1: drive supports 16-sector PIO
transfers, LBA48 addressing
Mar 12 03:21:05 frazzle /netbsd: wd1: 58644 MB, 119150 cyl, 16 head,
63 sec, 512 bytes/sect x 120103200 sectors
Mar 12 03:21:05 frazzle /netbsd: wd1: drive supports PIO mode 4, DMA
mode 2, Ultra-DMA mode 5 (Ultra/100)
Mar 12 03:21:05 frazzle /netbsd: boot device: wd0
Mar 12 03:21:05 frazzle /netbsd: root on wd0a dumps on wd0b
Mar 12 03:21:05 frazzle /netbsd: root file system type: ffs
Mar 12 03:21:05 frazzle /netbsd: fxp0: Microcode loaded: int delay:
1000 usec, max bundle: 6
Mar 12 03:21:05 frazzle /netbsd: wsdisplay0: screen 4 added (80x25,
vt100 emulation)
Mar 12 03:21:06 frazzle savecore: no core dump
Mar 12 03:21:07 frazzle rpc.statd: Starting
Mar 12 03:21:07 frazzle rpc.lockd: Starting
Mar 12 03:21:12 frazzle xenstored: Checking store ...
Mar 12 03:21:12 frazzle xenstored: Checking store complete.
Mar 12 03:21:16 frazzle /netbsd: xvif1.0: Ethernet address 00:bd:c4:13:00:d1
Mar 12 03:21:17 frazzle /netbsd: xbd backend: attach device vnd0d
(size 786432) for domain 1
Mar 12 03:21:17 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/1/0/script (No such file or directory)
Mar 12 03:21:19 frazzle /netbsd: xbd backend 0x1 for domain 1 using
event channel 18, protocol x86_64-abi
Mar 12 03:21:19 frazzle /netbsd: xvif2.0: Ethernet address 00:bd:c4:13:00:d3
Mar 12 03:21:19 frazzle /netbsd: xbd backend: attach device vnd1d
(size 786432) for domain 2
Mar 12 03:21:27 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/2/0/script (No such file or directory)
Mar 12 03:21:30 frazzle /netbsd: xbd backend 0x1 for domain 2 using
event channel 22, protocol x86_64-abi
Mar 12 03:21:31 frazzle /netbsd: xvif3.0: Ethernet address 00:bd:c4:13:00:d6
Mar 12 03:21:31 frazzle /netbsd: xbd backend: attach device vnd2d
(size 786432) for domain 3
Mar 12 03:21:39 frazzle /netbsd: xbd backend: detach device vnd0d for domain 1
Mar 12 03:21:39 frazzle /netbsd: xvif1.0: disconnecting
Mar 12 03:21:40 frazzle /netbsd: xvif4.0: Ethernet address 00:bd:c4:13:00:d1
Mar 12 03:21:41 frazzle /netbsd: xbd backend 0x1 for domain 4 using
event channel 26, protocol x86_64-abi
Mar 12 03:21:41 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/3/0/script (No such file or directory)
Mar 12 03:21:41 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/1/0/state (No such file or directory)
Mar 12 03:21:41 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/vbd/1/1/state (No such file or directory)
Mar 12 03:21:41 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/vif/1/0/state (No such file or directory)
Mar 12 03:21:42 frazzle /netbsd: xbdback backend/vbd/4/1: changing
physical device from 0x0 to 0xe03 not supported
Mar 12 03:21:43 frazzle /netbsd: xbd backend 0x1 for domain 3 using
event channel 28, protocol x86_64-abi
Mar 12 03:21:44 frazzle /netbsd: xvif5.0: Ethernet address 00:bd:c4:13:00:d7
Mar 12 03:21:44 frazzle /netbsd: xbd backend: attach device vnd3d
(size 786432) for domain 5
Mar 12 03:21:49 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/5/0/script (No such file or directory)
Mar 12 03:21:53 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/2/0/script (No such file or directory)
Mar 12 03:21:53 frazzle /netbsd: xbd backend: detach device vnd1d for domain 2
Mar 12 03:21:53 frazzle /netbsd: xvif2.0: disconnecting
Mar 12 03:21:55 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/6/0/script (No such file or directory)
Mar 12 03:21:55 frazzle /netbsd: xvif6.0: Ethernet address 00:bd:c4:13:00:d3
Mar 12 03:21:55 frazzle /netbsd: xbd backend: attach device vnd1d
(size 786432) for domain 6
Mar 12 03:21:56 frazzle /netbsd: xbd backend 0x1 for domain 5 using
event channel 32, protocol x86_64-abi
Mar 12 03:21:56 frazzle /netbsd: xbd backend 0x1 for domain 6 using
event channel 34, protocol x86_64-abi
Mar 12 03:21:59 frazzle /netbsd: xvif7.0: Ethernet address 00:bd:c4:13:00:d9
Mar 12 03:21:59 frazzle /netbsd: xbd backend: attach device vnd4d
(size 786432) for domain 7
Mar 12 03:22:01 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/7/0/script (No such file or directory)
Mar 12 03:22:05 frazzle /netbsd: xvif3.0 GNTTABOP_transfer[0] -1
Mar 12 03:22:05 frazzle /netbsd: xvif3.0: req_prod 256 req_cons 2
rsp_prod 1 rsp_prod_pvt 1 i 1
Mar 12 03:22:06 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/3/0/script (No such file or directory)
Mar 12 03:22:06 frazzle /netbsd: xbd backend: detach device vnd2d for domain 3
Mar 12 03:22:06 frazzle /netbsd: xvif3.0: disconnecting
Mar 12 03:22:08 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/8/0/script (No such file or directory)
Mar 12 03:22:10 frazzle /netbsd: xvif8.0: Ethernet address 00:bd:c4:13:00:d6
Mar 12 03:22:10 frazzle /netbsd: xbd backend: attach device vnd2d
(size 786432) for domain 8
Mar 12 03:22:12 frazzle /netbsd: xbd backend 0x1 for domain 8 using
event channel 38, protocol x86_64-abi
Mar 12 03:22:15 frazzle /netbsd: xbd backend 0x1 for domain 7 using
event channel 40, protocol x86_64-abi
Mar 12 03:22:16 frazzle /netbsd: xvif9.0: Ethernet address 00:bd:c4:13:00:d8
Mar 12 03:22:16 frazzle /netbsd: xbd backend: attach device vnd5d
(size 786432) for domain 9
Mar 12 03:22:18 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/9/0/script (No such file or directory)
Mar 12 03:22:22 frazzle /netbsd: xbd backend 0x1 for domain 9 using
event channel 44, protocol x86_64-abi
Mar 12 03:22:24 frazzle /netbsd: xbd backend: attach device vnd6d
(size 786432) for domain 10
Mar 12 03:22:24 frazzle /netbsd: xvif10.0: Ethernet address 00:bd:c4:13:00:d0
Mar 12 03:22:26 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/10/0/script (No such file or
directory)
Mar 12 03:22:31 frazzle /netbsd: xbd backend 0x1 for domain 10 using
event channel 48, protocol x86_64-abi
Mar 12 03:22:33 frazzle /netbsd: xvif11.0: Ethernet address 00:bd:c4:13:00:d4
Mar 12 03:22:39 frazzle /netbsd: xbd backend: attach device vnd7d
(size 786432) for domain 11
Mar 12 03:22:39 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/11/0/script (No such file or
directory)
Mar 12 03:22:41 frazzle /netbsd: xbd backend 0x1 for domain 11 using
event channel 52, protocol x86_64-abi
Mar 12 03:22:43 frazzle /netbsd: xvif12.0: Ethernet address 00:bd:c4:13:00:d5
Mar 12 03:22:47 frazzle /netbsd: xbd backend: attach device vnd8d
(size 786432) for domain 12
Mar 12 03:22:48 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/12/0/script (No such file or
directory)
Mar 12 03:22:51 frazzle /netbsd: xbd backend 0x1 for domain 12 using
event channel 56, protocol x86_64-abi
Mar 12 03:22:53 frazzle /netbsd: xvif13.0: Ethernet address 00:bd:c4:13:00:ec
Mar 12 03:22:53 frazzle /netbsd: xbd backend: attach device vnd9d
(size 1136640) for domain 13
Mar 12 03:22:55 frazzle /netbsd: xbd backend: attach device vnd10d
(size 1136640) for domain 13
Mar 12 03:22:56 frazzle /netbsd: xbd backend: attach device vnd11d
(size 2275328) for domain 13
Mar 12 03:22:58 frazzle /netbsd: xbd backend: attach device vnd12d
(size 4550656) for domain 13
Mar 12 03:22:59 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/13/0/script (No such file or
directory)
Mar 12 03:23:34 frazzle /netbsd: xbd backend 0x1 for domain 13 using
event channel 60, protocol x86_64-abi
Mar 12 03:23:34 frazzle /netbsd: xbd backend 0x2 for domain 13 using
event channel 61, protocol x86_64-abi
Mar 12 03:23:34 frazzle /netbsd: xbd backend 0x3 for domain 13 using
event channel 62, protocol x86_64-abi
Mar 12 03:23:34 frazzle /netbsd: xbd backend 0x4 for domain 13 using
event channel 63, protocol x86_64-abi
Mar 12 03:24:25 frazzle /netbsd: xvif5.0 GNTTABOP_transfer[0] -1
Mar 12 03:24:25 frazzle /netbsd: xvif5.0: req_prod 256 req_cons 101
rsp_prod 100 rsp_prod_pvt 100 i 1
Mar 12 03:24:29 frazzle /netbsd: xvif5.0 GNTTABOP_transfer[0] -1
Mar 12 03:24:29 frazzle /netbsd: xvif5.0: req_prod 256 req_cons 102
rsp_prod 101 rsp_prod_pvt 101 i 1
Mar 12 03:24:30 frazzle /netbsd: xbd backend: detach device vnd3d for domain 5
Mar 12 03:24:30 frazzle /netbsd: xvif5.0: disconnecting
Mar 12 03:24:33 frazzle /netbsd: xvif14.0: Ethernet address 00:bd:c4:13:00:d7
Mar 12 03:24:35 frazzle /netbsd: xbd backend 0x1 for domain 14 using
event channel 65, protocol x86_64-abi
Mar 12 03:24:39 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/5/0/state (No such file or directory)
Mar 12 03:24:39 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/vbd/5/1/state (No such file or directory)
Mar 12 03:24:39 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/vif/5/0/state (No such file or directory)
Mar 12 03:24:39 frazzle /netbsd: xbdback backend/vbd/14/1: changing
physical device from 0x0 to 0xe33 not supported
Mar 12 03:26:05 frazzle /netbsd: xvif10.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:05 frazzle /netbsd: xvif10.0: req_prod 371 req_cons 144
rsp_prod 143 rsp_prod_pvt 143 i 1
Mar 12 03:26:15 frazzle /netbsd: xvif12.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:15 frazzle /netbsd: xvif12.0: req_prod 256 req_cons 116
rsp_prod 115 rsp_prod_pvt 115 i 1
Mar 12 03:26:15 frazzle /netbsd: xvif11.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:15 frazzle /netbsd: xvif11.0: req_prod 256 req_cons 143
rsp_prod 142 rsp_prod_pvt 142 i 1
Mar 12 03:26:15 frazzle /netbsd: xvif10.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:15 frazzle /netbsd: xvif10.0: req_prod 371 req_cons 145
rsp_prod 144 rsp_prod_pvt 144 i 1
Mar 12 03:26:24 frazzle /netbsd: xvif12.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:24 frazzle /netbsd: xvif12.0: req_prod 256 req_cons 117
rsp_prod 116 rsp_prod_pvt 116 i 1
Mar 12 03:26:24 frazzle /netbsd: xvif11.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:24 frazzle /netbsd: xvif11.0: req_prod 256 req_cons 144
rsp_prod 143 rsp_prod_pvt 143 i 1
Mar 12 03:26:24 frazzle /netbsd: xvif10.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:24 frazzle /netbsd: xvif10.0: req_prod 371 req_cons 146
rsp_prod 145 rsp_prod_pvt 145 i 1
Mar 12 03:26:27 frazzle /netbsd: xvif12.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:27 frazzle /netbsd: xvif12.0: req_prod 256 req_cons 118
rsp_prod 117 rsp_prod_pvt 117 i 1
Mar 12 03:26:27 frazzle /netbsd: xvif11.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:27 frazzle /netbsd: xvif11.0: req_prod 256 req_cons 145
rsp_prod 144 rsp_prod_pvt 144 i 1
Mar 12 03:26:27 frazzle /netbsd: xvif10.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:27 frazzle /netbsd: xvif10.0: req_prod 371 req_cons 147
rsp_prod 146 rsp_prod_pvt 146 i 1
Mar 12 03:26:34 frazzle /netbsd: xvif12.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:34 frazzle /netbsd: xvif12.0: req_prod 256 req_cons 121
rsp_prod 118 rsp_prod_pvt 118 i 3
Mar 12 03:26:34 frazzle /netbsd: xvif12.0 GNTTABOP_transfer[1] -1
Mar 12 03:26:34 frazzle /netbsd: xvif12.0: req_prod 256 req_cons 121
rsp_prod 118 rsp_prod_pvt 118 i 3
Mar 12 03:26:34 frazzle /netbsd: xvif12.0 GNTTABOP_transfer[2] -1
Mar 12 03:26:34 frazzle /netbsd: xvif12.0: req_prod 256 req_cons 121
rsp_prod 118 rsp_prod_pvt 118 i 3
Mar 12 03:26:34 frazzle /netbsd: xvif11.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:34 frazzle /netbsd: xvif11.0: req_prod 256 req_cons 148
rsp_prod 145 rsp_prod_pvt 145 i 3
Mar 12 03:26:34 frazzle /netbsd: xvif11.0 GNTTABOP_transfer[1] -1
Mar 12 03:26:34 frazzle /netbsd: xvif11.0: req_prod 256 req_cons 148
rsp_prod 145 rsp_prod_pvt 145 i 3
Mar 12 03:26:34 frazzle /netbsd: xvif11.0 GNTTABOP_transfer[2] -1
Mar 12 03:26:34 frazzle /netbsd: xvif11.0: req_prod 256 req_cons 148
rsp_prod 145 rsp_prod_pvt 145 i 3
Mar 12 03:26:34 frazzle /netbsd: xvif10.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:34 frazzle /netbsd: xvif10.0: req_prod 371 req_cons 150
rsp_prod 147 rsp_prod_pvt 147 i 3
Mar 12 03:26:34 frazzle /netbsd: xvif10.0 GNTTABOP_transfer[1] -1
Mar 12 03:26:34 frazzle /netbsd: xvif10.0: req_prod 371 req_cons 150
rsp_prod 147 rsp_prod_pvt 147 i 3
Mar 12 03:26:34 frazzle /netbsd: xvif10.0 GNTTABOP_transfer[2] -1
Mar 12 03:26:34 frazzle /netbsd: xvif10.0: req_prod 371 req_cons 150
rsp_prod 147 rsp_prod_pvt 147 i 3
Mar 12 03:26:34 frazzle /netbsd: xvif12.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:34 frazzle /netbsd: xvif12.0: req_prod 256 req_cons 122
rsp_prod 121 rsp_prod_pvt 121 i 1
Mar 12 03:26:34 frazzle /netbsd: xvif11.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:34 frazzle /netbsd: xvif11.0: req_prod 256 req_cons 149
rsp_prod 148 rsp_prod_pvt 148 i 1
Mar 12 03:26:34 frazzle /netbsd: xvif10.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:34 frazzle /netbsd: xvif10.0: req_prod 371 req_cons 151
rsp_prod 150 rsp_prod_pvt 150 i 1
Mar 12 03:26:35 frazzle /netbsd: xvif12.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:35 frazzle /netbsd: xvif12.0: req_prod 256 req_cons 123
rsp_prod 122 rsp_prod_pvt 122 i 1
Mar 12 03:26:35 frazzle /netbsd: xvif11.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:35 frazzle /netbsd: xvif11.0: req_prod 256 req_cons 150
rsp_prod 149 rsp_prod_pvt 149 i 1
Mar 12 03:26:35 frazzle /netbsd: xvif10.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:35 frazzle /netbsd: xvif10.0: req_prod 371 req_cons 152
rsp_prod 151 rsp_prod_pvt 151 i 1
Mar 12 03:26:35 frazzle /netbsd: xvif12.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:35 frazzle /netbsd: xvif12.0: req_prod 256 req_cons 124
rsp_prod 123 rsp_prod_pvt 123 i 1
Mar 12 03:26:35 frazzle /netbsd: xvif11.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:35 frazzle /netbsd: xvif11.0: req_prod 256 req_cons 151
rsp_prod 150 rsp_prod_pvt 150 i 1
Mar 12 03:26:35 frazzle /netbsd: xvif10.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:35 frazzle /netbsd: xvif10.0: req_prod 371 req_cons 153
rsp_prod 152 rsp_prod_pvt 152 i 1
Mar 12 03:26:36 frazzle /netbsd: xvif12.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:36 frazzle /netbsd: xvif12.0: req_prod 256 req_cons 125
rsp_prod 124 rsp_prod_pvt 124 i 1
Mar 12 03:26:36 frazzle /netbsd: xvif11.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:36 frazzle /netbsd: xvif11.0: req_prod 256 req_cons 152
rsp_prod 151 rsp_prod_pvt 151 i 1
Mar 12 03:26:36 frazzle /netbsd: xvif10.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:36 frazzle /netbsd: xvif10.0: req_prod 371 req_cons 154
rsp_prod 153 rsp_prod_pvt 153 i 1
Mar 12 03:26:37 frazzle /netbsd: xvif12.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:37 frazzle /netbsd: xvif12.0: req_prod 256 req_cons 126
rsp_prod 125 rsp_prod_pvt 125 i 1
Mar 12 03:26:37 frazzle /netbsd: xvif11.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:37 frazzle /netbsd: xvif11.0: req_prod 256 req_cons 153
rsp_prod 152 rsp_prod_pvt 152 i 1
Mar 12 03:26:37 frazzle /netbsd: xvif10.0 GNTTABOP_transfer[0] -1
Mar 12 03:26:37 frazzle /netbsd: xvif10.0: req_prod 371 req_cons 155
rsp_prod 154 rsp_prod_pvt 154 i 1
Mar 12 03:26:41 frazzle /netbsd: xbd backend: detach device vnd6d for domain 10
Mar 12 03:26:41 frazzle /netbsd: xvif10.0: disconnecting
Mar 12 03:26:43 frazzle /netbsd: xbd backend: detach device vnd8d for domain 12
Mar 12 03:26:43 frazzle /netbsd: xvif12.0: disconnecting
Mar 12 03:26:43 frazzle /netbsd: xbd backend: detach device vnd7d for domain 11
Mar 12 03:26:43 frazzle /netbsd: xvif11.0: disconnecting
Mar 12 03:26:44 frazzle /netbsd: xvif15.0: Ethernet address 00:bd:c4:13:00:d0
Mar 12 03:26:46 frazzle /netbsd: xbd backend 0x1 for domain 15 using
event channel 50, protocol x86_64-abi
Mar 12 03:26:53 frazzle /netbsd: xvif16.0: Ethernet address 00:bd:c4:13:00:d4
Mar 12 03:26:56 frazzle /netbsd: xbd backend 0x1 for domain 16 using
event channel 67, protocol x86_64-abi
Mar 12 03:27:11 frazzle /netbsd: xvif17.0: Ethernet address 00:bd:c4:13:00:d5
Mar 12 03:27:14 frazzle /netbsd: xbd backend 0x1 for domain 17 using
event channel 71, protocol x86_64-abi
Mar 12 03:27:19 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/12/0/state (No such file or directory)
Mar 12 03:27:20 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/10/0/state (No such file or directory)
Mar 12 03:27:20 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/vbd/10/1/state (No such file or directory)
Mar 12 03:27:20 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/vif/10/0/state (No such file or directory)
Mar 12 03:27:20 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/11/0/state (No such file or directory)
Mar 12 03:27:20 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/vbd/12/1/state (No such file or directory)
Mar 12 03:27:20 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/vif/12/0/state (No such file or directory)
Mar 12 03:27:20 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/vbd/11/1/state (No such file or directory)
Mar 12 03:27:20 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/vif/11/0/state (No such file or directory)
Mar 12 03:27:20 frazzle /netbsd: xbdback backend/vbd/15/1: changing
physical device from 0x0 to 0xe63 not supported
Mar 12 03:27:20 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/16/0/script (No such file or
directory)
Mar 12 03:27:20 frazzle /netbsd: xbdback backend/vbd/16/1: changing
physical device from 0x0 to 0xe73 not supported
Mar 12 03:27:20 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/17/0/script (No such file or
directory)
Mar 12 03:27:20 frazzle /netbsd: xbdback backend/vbd/17/1: changing
physical device from 0x0 to 0xe83 not supported
Mar 12 04:13:45 frazzle /netbsd: umass0 at uhub3 port 2 configuration
1 interface 0
Mar 12 04:13:45 frazzle /netbsd:
Mar 12 04:13:45 frazzle /netbsd: umass0: Super Top USB 2.0  IDE
DEVICE, rev 2.00/2.01, addr 2
Mar 12 04:13:45 frazzle /netbsd: umass0: using SCSI over Bulk-Only
Mar 12 04:13:45 frazzle /netbsd: scsibus0 at umass0: 2 targets, 1 lun per target
Mar 12 04:13:45 frazzle /netbsd: sd0 at scsibus0 target 0 lun 0:
<Maxtor 2, F020J1, 0\0000> disk fixed
Mar 12 04:13:45 frazzle /netbsd: sd0: 19881 MB, 16383 cyl, 16 head, 63
sec, 512 bytes/sect x 40718160 sectors
Mar 12 04:20:37 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/16/0/script (No such file or
directory)
Mar 12 04:20:37 frazzle /netbsd: xvif16.0: disconnecting
Mar 12 04:20:39 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/18/0/script (No such file or
directory)
Mar 12 04:20:40 frazzle /netbsd: xvif18.0: Ethernet address 00:bd:c4:13:00:d4
Mar 12 04:20:40 frazzle /netbsd: xbd backend: attach device vnd7d
(size 786432) for domain 18
Mar 12 04:20:42 frazzle /netbsd: xbd backend 0x1 for domain 18 using
event channel 73, protocol x86_64-abi
Mar 12 04:28:01 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/4/0/script (No such file or directory)
Mar 12 04:28:01 frazzle /netbsd: xvif4.0: disconnecting
Mar 12 04:28:03 frazzle xenbackendd[253]: Failed to read
/local/domain/0/backend/console/19/0/script (No such file or
directory)
Mar 12 04:28:04 frazzle /netbsd: xvif19.0: Ethernet address 00:bd:c4:13:00:d1
Mar 12 04:28:04 frazzle /netbsd: xbd backend: attach device vnd0d
(size 786432) for domain 19
Mar 12 04:28:05 frazzle /netbsd: xbd backend 0x1 for domain 19 using
event channel 75, protocol x86_64-abi

I noticed also if a domain is restarted that networking is not set-up.
I have to manually ifconfig xvif18.0 up && brconig bridge0 add
xvif18.0