[Qemu-devel] HT problem

[Qemu-devel] HT problem

[Kazu]

Hi,

I have a report that when hyper-threading is on, Linux doesn't boot on
Windows XP. It occurs when linux kernel is loading. But when HT is turned 
off, qemu works fine. Does this occur on Linux host ?

Host: Windows XP SP2
Guest : linux-test image
QEMU version : 0.8.0
ASUS P4P800 Deluxe
Intel Pentium4 3.0GHz
DDR400 512MB x 2

Regards,
Kazu

Re: [Qemu-devel] HT problem

[malc]

On Fri, 23 Dec 2005, Kazu wrote:

> Hi,
>
> I have a report that when hyper-threading is on, Linux doesn't boot on
> Windows XP. It occurs when linux kernel is loading. But when HT is turned 
> off, qemu works fine. Does this occur on Linux host ?
>
> Host: Windows XP SP2
> Guest : linux-test image
> QEMU version : 0.8.0
> ASUS P4P800 Deluxe
> Intel Pentium4 3.0GHz
> DDR400 512MB x 2

No the problem is unique to Windows hosts (running SMP or HT), and is due
to the fact that QEMU is not MT safe and the fact that MM callback is
called on the separate thread. The fact it worked at all (and works on
UP now) is a simple luck. None of the attempts to hack around the issue
was successful so far. TODO lists this as short term item.

P.S. The increased frequency in the call of timeSetEvent (1 now was 10
      before) is what's causing this.

-- 
mailto:malc@pulsesoft.com

Re: [Qemu-devel] HT problem

[Kazu]

Hi, marc.

Friday, December 23, 2005 marc wrote:

> No the problem is unique to Windows hosts (running SMP or HT), and is due
> to the fact that QEMU is not MT safe and the fact that MM callback is
> called on the separate thread. The fact it worked at all (and works on
> UP now) is a simple luck. None of the attempts to hack around the issue
> was successful so far. TODO lists this as short term item.
> 
> P.S. The increased frequency in the call of timeSetEvent (1 now was 10
>      before) is what's causing this.
> 

Thanks. Now I got it.

Regards,
Kazu

Re: [Qemu-devel] HT problem

[malc]

On Fri, 23 Dec 2005, Kazu wrote:

> Hi,
>
> I have a report that when hyper-threading is on, Linux doesn't boot on
> Windows XP. It occurs when linux kernel is loading. But when HT is turned 
> off, qemu works fine. Does this occur on Linux host ?

Jari Komppa made a launcher that sets affinities just right to run QEMU on
Windows HT/MP systems.

The binary and source are available at:

http://sol.gfxile.net/ (http://sol.gfxile.net/files/splauncher.zip)

-- 
mailto:malc@pulsesoft.com

Re: [Qemu-devel] HT problem

[Kazu]

Sunday, January 15, 2006 6:43 AM malc wrote:

> On Fri, 23 Dec 2005, Kazu wrote:
>
>> Hi,
>>
>> I have a report that when hyper-threading is on, Linux doesn't boot on
>> Windows XP. It occurs when linux kernel is loading. But when HT is turned
>> off, qemu works fine. Does this occur on Linux host ?
>
> Jari Komppa made a launcher that sets affinities just right to run QEMU on
> Windows HT/MP systems.
>
> The binary and source are available at:
>
> http://sol.gfxile.net/ (http://sol.gfxile.net/files/splauncher.zip)
>

Great! I asked my friends and got a report that it works on HT system..

Regard,
Kazu