Tuning guide, -cpu host crashes hosted VM

Tuning guide, -cpu host crashes hosted VM

[Steven Ball]

Howdy all,

I am attempting to evaluate a few different virtualization platforms.  I've been going about this by installing a really basic XP host, and running some benchmarks.  I realize these are synthetic benchmarks, but it at least allows me to see how the virtualization platforms differ.

I attempted to do some tuning with KVM as per the tuning guide, using -cpu host, and as soon as my benchmarking program under XP uses a sse instruction, I get a blue screen crash and reboot.

The host system is a dual proc quad core Xeon E5506 2.13Ghz.

/proc/cpuinfo gives me these flags:

flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm tpr_shadow vnmi flexpriority ept vpid

I'm running Ubuntu 9.10, using their kvm package, which reports:

# kvm --version
QEMU PC emulator version 0.11.0 (qemu-kvm-0.11.0), Copyright (c) 2003-2008 Fabrice Bellard

I've tried using -cpu qemu64,+ssse3,+sse4.1,+sse4.2,+x2apic and it still crashes.  I also get:

CPU feature sse4.1 not found
CPU feature sse4.2 not found

So, any suggestions?  I can live without these extensions, but I'm just trying to compare apples to apples to get a better view of performance.  If there is a better Debian-based distro to be using, or if I should be compiling kvm from source, that is a fine suggestion too, just give an idea of where to start looking ;)

Thanks!

Re: Tuning guide, -cpu host crashes hosted VM

[Avi Kivity]

On 12/16/2009 12:33 AM, Steven Ball wrote:
> Howdy all,
>
> I am attempting to evaluate a few different virtualization platforms.  I've been going about this by installing a really basic XP host, and running some benchmarks.  I realize these are synthetic benchmarks, but it at least allows me to see how the virtualization platforms differ.
>
> I attempted to do some tuning with KVM as per the tuning guide, using -cpu host, and as soon as my benchmarking program under XP uses a sse instruction, I get a blue screen crash and reboot.
>    

Any idea what the instruction is?  You can set Windows to collect a 
crash dump, then use windbg to examine the dump and it will point out 
the offending instruction.

Alternatively, post a pointer to the application and someone may 
reproduce it some day.

-- 
error compiling committee.c: too many arguments to function