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From: Tim C. <tim...@li...> - 2007-01-25 23:34:54
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Hi,
I am only able to bring up a single cpu on my guest even when I
specify a 4 cpu smp config. My test machine
is a two socket dual core woodcrest with 4GB RAM. I am
using a stock RHEL5 kernel on my guest and 2.6.20-rc5
on my host.
The command I used is:
qemu-kvm -hda vdisk2.img -smp 4 -boot c -m 1024 -no-acpi
I've tried also without -no-acpi with the same result.
Now when I switch to qemu-system-x86_64 without kvm, the guest boots
with all 4 cpus being specified.
>From the boot log, it looks like it is APIC related.
Is this a known problem?
Thanks.
Tim Chen
------------Boot log on guest below----------------
boot log for command
qemu-kvm -hda vdisk2.img -smp 4 -boot c -m 1024 -no-acpi
Linux version 2.6.18-1.3002.el5 (bre...@hs...) (gcc version 4.1.1 20070105 (Red Hat 4.1.1-51)) #1 SMP Tue Jan 9 21:19:58 EST 2007
Command line: ro root=LABEL=/ rhgb quiet
BIOS-provided physical RAM map:
BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
BIOS-e820: 00000000000e8000 - 0000000000100000 (reserved)
BIOS-e820: 0000000000100000 - 0000000040000000 (usable)
BIOS-e820: 00000000fffc0000 - 0000000100000000 (reserved)
DMI not present or invalid.
ACPI: Unable to locate RSDP
No NUMA configuration found
Faking a node at 0000000000000000-0000000040000000
Bootmem setup node 0 0000000000000000-0000000040000000
Intel MultiProcessor Specification v1.4
Virtual Wire compatibility mode.
OEM ID: QEMUCPU Product ID: 0.1 APIC at: 0xFEE00000
Processor #0 6:0 APIC version 17
Processor #1 6:0 APIC version 17
Processor #2 6:0 APIC version 17
Processor #3 6:0 APIC version 17
I/O APIC #4 Version 17 at 0xFEC00000.
Setting APIC routing to physical flat
Processors: 4
Nosave address range: 000000000009f000 - 00000000000a0000
Nosave address range: 00000000000a0000 - 00000000000e8000
Nosave address range: 00000000000e8000 - 0000000000100000
Allocating PCI resources starting at 50000000 (gap: 40000000:bffc0000)
SMP: Allowing 4 CPUs, 0 hotplug CPUs
Built 1 zonelists. Total pages: 257255
Kernel command line: ro root=LABEL=/ rhgb quiet
Initializing CPU#0
PID hash table entries: 4096 (order: 12, 32768 bytes)
Console: colour VGA+ 80x25
Dentry cache hash table entries: 131072 (order: 8, 1048576 bytes)
Inode-cache hash table entries: 65536 (order: 7, 524288 bytes)
Checking aperture...
Memory: 1025624k/1048576k available (2397k kernel code, 22564k reserved, 1222k data, 196k init)
Calibrating delay using timer specific routine.. 5372.61 BogoMIPS (lpj=2686305)
Security Framework v1.0.0 initialized
SELinux: Initializing.
SELinux: Starting in permissive mode
selinux_register_security: Registering secondary module capability
Capability LSM initialized as secondary
Mount-cache hash table entries: 256
CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)
CPU: L2 Cache: 512K (64 bytes/line)
CPU 0/0 -> Node 0
SMP alternatives: switching to UP code
Using IO-APIC 4
activating NMI Watchdog ... done.
Using local APIC timer interrupts.
result 4636414
Detected 4.636 MHz APIC timer.
SMP alternatives: switching to SMP code
Booting processor 1/4 APIC 0x1
Not responding.
Inquiring remote APIC #1...
... APIC #1 ID: failed
... APIC #1 VERSION: failed
... APIC #1 SPIV: failed
SMP alternatives: switching to SMP code
Booting processor 2/3 APIC 0x2
Not responding.
Inquiring remote APIC #2...
... APIC #2 ID: failed
... APIC #2 VERSION: failed
... APIC #2 SPIV: failed
SMP alternatives: switching to SMP code
Booting processor 3/2 APIC 0x3
Not responding.
Inquiring remote APIC #3...
... APIC #3 ID: failed
... APIC #3 VERSION: failed
... APIC #3 SPIV: failed
Brought up 1 CPUs
testing NMI watchdog ... CPU#0: NMI appears to be stuck (0->0)!
-----------------------------------------------------
Boot log for sucessfule brought up of 4 cpus with command:
qemu-system-x86_64 -hda vdisk2.img -smp 4 -boot c -m 1024 -no-acpi
Linux version 2.6.18-1.3002.el5 (bre...@hs...) (gcc version 4.1.1 20070105 (Red Hat 4.1.1-51)) #1 SMP Tue Jan 9 21:19:58 EST 2007
Command line: ro root=LABEL=/ rhgb acpi=off
BIOS-provided physical RAM map:
BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
BIOS-e820: 00000000000e8000 - 0000000000100000 (reserved)
BIOS-e820: 0000000000100000 - 0000000040000000 (usable)
BIOS-e820: 00000000fffc0000 - 0000000100000000 (reserved)
DMI not present or invalid.
No NUMA configuration found
Faking a node at 0000000000000000-0000000040000000
Bootmem setup node 0 0000000000000000-0000000040000000
Intel MultiProcessor Specification v1.4
Virtual Wire compatibility mode.
OEM ID: QEMUCPU Product ID: 0.1 APIC at: 0xFEE00000
Processor #0 6:0 APIC version 17
Processor #1 6:0 APIC version 17
Processor #2 6:0 APIC version 17
Processor #3 6:0 APIC version 17
I/O APIC #4 Version 17 at 0xFEC00000.
Setting APIC routing to physical flat
Processors: 4
Nosave address range: 000000000009f000 - 00000000000a0000
Nosave address range: 00000000000a0000 - 00000000000e8000
Nosave address range: 00000000000e8000 - 0000000000100000
Allocating PCI resources starting at 50000000 (gap: 40000000:bffc0000)
SMP: Allowing 4 CPUs, 0 hotplug CPUs
Built 1 zonelists. Total pages: 257255
Kernel command line: ro root=LABEL=/ rhgb acpi=off
Initializing CPU#0
PID hash table entries: 4096 (order: 12, 32768 bytes)
Console: colour VGA+ 80x25
Dentry cache hash table entries: 131072 (order: 8, 1048576 bytes)
Inode-cache hash table entries: 65536 (order: 7, 524288 bytes)
Checking aperture...
Memory: 1025624k/1048576k available (2397k kernel code, 22564k reserved, 1222k data, 196k init)
Calibrating delay using timer specific routine.. 5481.21 BogoMIPS (lpj=2740609)
Security Framework v1.0.0 initialized
SELinux: Initializing.
SELinux: Starting in permissive mode
selinux_register_security: Registering secondary module capability
Capability LSM initialized as secondary
Mount-cache hash table entries: 256
starting audispd
CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)
CPU: L2 Cache: 512K (64 bytes/line)
CPU 0/0 -> Node 0
SMP alternatives: switching to UP code
Using IO-APIC 4
activating NMI Watchdog ... done.
Using local APIC timer interrupts.
result 62501278
Detected 62.501 MHz APIC timer.
SMP alternatives: switching to SMP code
Booting processor 1/4 APIC 0x1
Initializing CPU#1
calibrate_delay_direct() failed to get a good estimate for loops_per_jiffy.
Probably due to long platform interrupts. Consider using "lpj=" boot option.
CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)
CPU: L2 Cache: 512K (64 bytes/line)
CPU 1/0 -> Node 0
QEMU Virtual CPU version 0.8.2 stepping 03
CPU 1: Syncing TSC to CPU 0.
CPU 1: synchronized TSC with CPU 0 (last diff -108 cycles, maxerr 5205480 cycles)
SMP alternatives: switching to SMP code
Booting processor 2/4 APIC 0x2
Initializing CPU#2
calibrate_delay_direct() failed to get a good estimate for loops_per_jiffy.
Probably due to long platform interrupts. Consider using "lpj=" boot option.
CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)
CPU: L2 Cache: 512K (64 bytes/line)
CPU 2/0 -> Node 0
QEMU Virtual CPU version 0.8.2 stepping 03
CPU 2: Syncing TSC to CPU 0.
CPU 2: synchronized TSC with CPU 0 (last diff 1312276 cycles, maxerr 7810648 cycles)
SMP alternatives: switching to SMP code
Booting processor 3/4 APIC 0x3
Initializing CPU#3
calibrate_delay_direct() failed to get a good estimate for loops_per_jiffy.
Probably due to long platform interrupts. Consider using "lpj=" boot option.
CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)
CPU: L2 Cache: 512K (64 bytes/line)
CPU 3/0 -> Node 0
QEMU Virtual CPU version 0.8.2 stepping 03
CPU 3: Syncing TSC to CPU 0.
CPU 3: synchronized TSC with CPU 0 (last diff 2613452 cycles, maxerr 10414152 cycles)
Brought up 4 CPUs
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From: Matthew H. <ma...@ca...> - 2007-01-26 06:07:21
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Tim Chen wrote: > Now when I switch to qemu-system-x86_64 without kvm, the guest boots > with all 4 cpus being specified. > >>From the boot log, it looks like it is APIC related. > Is this a known problem? Boot the /host/ kernel with 'noapic nolapic' and see if that makes a difference for you. There is a performance impact under load, but it made a world of difference for me when I had issues which were similarly kvm specific. Matt |
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From: Tim C. <tim...@li...> - 2007-01-26 17:50:17
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On Fri, 2007-01-26 at 06:06 +0000, Matthew Hall wrote: > > Boot the /host/ kernel with 'noapic nolapic' and see if that makes a > difference for you. There is a performance impact under load, but it > made a world of difference for me when I had issues which were similarly > kvm specific. Unfortunately, that did not solve the problem and I see the same error in my boot log as previously reported. Tim |
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From: Avi K. <av...@qu...> - 2007-01-26 17:59:17
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Tim Chen wrote: > Hi, > > I am only able to bring up a single cpu on my guest even when I > specify a 4 cpu smp config. My test machine > is a two socket dual core woodcrest with 4GB RAM. I am > using a stock RHEL5 kernel on my guest and 2.6.20-rc5 > on my host. > > The command I used is: > qemu-kvm -hda vdisk2.img -smp 4 -boot c -m 1024 -no-acpi > > I've tried also without -no-acpi with the same result. > > kvm only supports uniprocessor guests at this time. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. |
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From: Matthew H. <ma...@ca...> - 2007-01-26 19:02:59
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Avi Kivity wrote: > kvm only supports uniprocessor guests at this time. Out of interest, if/when kvm supports smp guests aswell as hosts would the guest be presented with a multiple virtual or physical cpu's? Ie. If the guest has multiple virtual cpu's the process would only run as a single task which would then affine to a single cpu on a multiple cpu host. So could kvm let an smp guest share the physical cpu's the host has? Matt |
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From: Avi K. <av...@qu...> - 2007-01-27 08:27:25
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Matthew Hall wrote: > Avi Kivity wrote: > >> kvm only supports uniprocessor guests at this time. >> > > Out of interest, if/when when. > kvm supports smp guests aswell as hosts would > the guest be presented with a multiple virtual or physical cpu's? > Ie. If the guest has multiple virtual cpu's the process would only run > as a single task which would then affine to a single cpu on a multiple > cpu host. > > So could kvm let an smp guest share the physical cpu's the host has? > kvm maps a guest vcpu to a host thread. In turn, the host scheduler maps host threads to host cpus, so the mapping of vcpus to cpus depends on resource availability: if you have enough cpus, the scheduler will assign each vcpu to a separate cpu. The user will also be able to affect the mapping by binding vcpu threads to specific processors. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. |
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From: Tim C. <tim...@li...> - 2007-01-26 18:45:35
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On Fri, 2007-01-26 at 19:58 +0200, Avi Kivity wrote: > > > kvm only supports uniprocessor guests at this time. > Thanks for the clarification. Is SMP support for guests expected soon? The FAQ is a bit misleading: http://kvm.qumranet.com/kvmwiki/FAQ It says "Does kvm support SMP hosts? Yes". I misinterpreted it meaning that SMP support for guests is available. Tim |
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From: Avi K. <av...@qu...> - 2007-01-27 08:40:33
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Tim Chen wrote: > On Fri, 2007-01-26 at 19:58 +0200, Avi Kivity wrote: > >> >> >> kvm only supports uniprocessor guests at this time. >> >> > > Thanks for the clarification. Is SMP support for guests > expected soon? > For the next few weeks I plan to focus on stability, correctness, and a stable userspace interface. I will accept patches outside these areas, though. > The FAQ is a bit misleading: > http://kvm.qumranet.com/kvmwiki/FAQ > > It says "Does kvm support SMP hosts? Yes". > I misinterpreted it meaning that SMP > support for guests is available. > I added an entry for smp guests. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. |
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