Open MPI logo

Hardware Locality Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Hardware Locality Development mailing list

Subject: Re: [hwloc-devel] hwloc with Xen system support - v2
From: Brice Goglin (Brice.Goglin_at_[hidden])
Date: 2014-02-13 05:52:14


Le 13/02/2014 02:48, Andrew Cooper a écrit :
> That's fantastic! I was expecting to have to attempt to code this up myself.
>
> I hereby present v4 of the series, available from:
>
> http://xenbits.xen.org/gitweb/?p=people/andrewcoop/hwloc.git;a=shortlog;h=refs/heads/hwloc-xen-topology-v4
> http://xenbits.xen.org/gitweb/?p=people/andrewcoop/xen.git;a=shortlog;h=refs/heads/hwloc-support-experimental-v2
>
> Where the hwloc-xen-topology-v4 branch is now based on x86-common rather
> than master.
>
> hwloc-support-experimental-v2 in the Xen tree now contains two changes.
> In addition to the *_bounced() functions, there is a new SYSCTL
> hypercall for Xen to allow the toolstack to request execution of an
> arbitrary cpuid instruction on a specific processor. It seems to work
> in each of the usecases I had before, and now provides substantially
> more information.
>
> I suspect that the new cpuid function call needs to be properly guarded
> by the configure script; While the previous code was common to all Xen
> architectures, the cpuid sysctl is very definitely x86 specific.
>

I just *rebased* and repushed the x86-common branch. You now need to
#ifdef HWLOC_HAVE_X86_CPUID before calling the cpuid function. I have
also cleaned the namespace (to avoid possible conflicts with non-x86
cpuid-similar functions in the future). So you should replace "x86" with
"x86_cpuid" in the function name and in the flags.

Let me know if you see anything to change before I merge this into the
master branch.

Where are you on your side? Your code looks fine to me, but there was
some discussion about switching to another xen lib, and some possible
issue with the API/ABI changing without version numbers to check against.

Do you want to merge something in hwloc soon? I am thinking of releasing
hwloc v1.9 within one month or two. I am not against releasing the hwloc
Xen backend as long as we do not cause failures to build for many
people. If it's too hard, we could also keep it disabled by default
until hwloc v1.10?

Brice