Re: multiple vcpus in a domain

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Wed, Mar 10, 2021 at 08:11:25PM -0800, John Nemeth wrote:
> On Mar 10, 13:56, Greg Troxel wrote:
> } 
> } I wrote in the HOWTO that as of current NetBSD dom0 supports multiple
> } CPUs, and want to check that this is right.
> } 
> } I think:
> } 
> }    8, 9, current XEN3_DOMU all can have multiple vcpus and use them and
> }    this is basically working fine
> 
>      domU has been multiprocessor since 6.0.
> 
> }    8, 9 XEN3_DOM0 are not built with options MULTIPROCESSOR and if given
> }    >1 vcpu will just ignore all but one
> 
>      This is likely not true.  I ran a test server with dom0
> multiprocessor some time ago.

You've been lukcy then. Some parts of dom0 support is not MP-safe in -9.

> 
> }    current XEN3_DOM0 is built with MULTIPROCESSOR, and detects and uses
> }    multiple vcpus and everything is fine
> 
>      It will use multiple cpus, but I'm not certain that everything
> is fine.  Last I knew, there was still some work to be done on
> this, but I may be out of date here.  I would be very happy to be
> wrong here, since single processor dom0 is likely to be a major
> bottleneck.

dom0 is supposed to be MP-safe in HEAD now.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--