Re: SMP does not work as expected - was: Re: [Xen-users] Checking for SMP usage in xen stable

["Dirk H. Schulz" <dirk.schulz@xxxxxxxxxxxxx>]

Tom Brown schrieb:

> this is just the normal P4/xeon hyperthreading isn't it? I don't know what
> an IBM x335 is... so I'm just guessing that hyperthreading is available.
>  
Yes, this is a Xeon that can do hyperthreading - but does SMP in Xen 
also work on hyperthreaded single cpus? I thought that hyperthreading is 
different from SMP.
If that works I can distribute CPU power in finer chunks on a dual 
processor hyperthreading machine.
I will test that.

Dirk

> -Tom
>
> On Mon, 7 Nov 2005, Dirk H. Schulz wrote:
>
>  
>
> > Hi folks,
> >
> > I looked somewhat deeper into the smp issue with Xen 2.0.7. I found that
> > smp is used even on machines with only one processor.
> >
> > This is xm list on an IBM x335, a dual processor board with one processor:
> >
> >    Name                  Id    Mem(MB)    CPU        State  Time(s)
> > Console
> >    Domain-0            0    123                0            r----
> > 59931.7
> >    webdynown01    5    511                1            -b---
> > 193.5    9605
> >    webstatown01    1    255                0            -b---
> > 202.9    9601
> >
> > I have configured CPU usage in the domU's config files. So two of one
> > CPUs are used, it seems.
> >
> > This is xm list on a single processor machine:
> >
> >    Name                  Id        Mem(MB)    CPU        State
> > Time(s)  Console
> >    Domain-0            0        123                0
> > r----   5567.2
> >    sync01                 2        95                   0
> >    -b---      1.8    9602
> >
> > So it seems that on dual processor boards smp is somehow simulated if
> > there is just one processor present.
> >
> > Is this a bug, or does it make sense somehow?
> >
> > And now my original question comes up again: How can I - reliably -
> > verify that my xen kernel is running smp code?
> >
> > Dirk
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-users
> >
> >    
> ----------------------------------------------------------------------
> tbrown@xxxxxxxxxxxxx   | Courage is doing what you're afraid to do.
> http://BareMetal.com/  | There can be no courage unless you're scared.
>                       | - Eddie Rickenbacker
>
>  

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