[libvirt] [PATCH 1/1] cpu_map.xml: add cmt/mbm feature to x86

[Ren, Qiaowei]

> -----Original Message-----
> From: Daniel P. Berrange [mailto:berrange at redhat.com]
> Sent: Thursday, June 23, 2016 5:18 PM
> To: Ren, Qiaowei <qiaowei.ren at intel.com>; libvir-list at redhat.com; Peter
> Krempa <pkrempa at redhat.com>
> Subject: Re: [libvirt] [PATCH 1/1] cpu_map.xml: add cmt/mbm feature to x86
> 
> On Fri, Jun 17, 2016 at 11:17:47AM +0200, Jiri Denemark wrote:
> > On Fri, Jun 17, 2016 at 09:25:14 +0200, Jiri Denemark wrote:
> > > On Fri, Jun 17, 2016 at 09:23:56 +0800, Qiaowei Ren wrote:
> > > > Some Intel processor families (e.g. the Intel Xeon processor E5 v3
> > > > family) introduced some PQos (Platform Qos) features, including
> > > > CMT (Cache Monitoring echnology) and MBM (Memory Bandwidth
> > > > Monitoring), to monitor or control shared resource. This patch add
> > > > them into x86 part of cpu_map.xml to be used for applications
> > > > (like OpenStack) based on libvirt to get cpu capabilities.
> > > >
> > > > Signed-off-by: Qiaowei Ren <qiaowei.ren at intel.com>
> > > > ---
> > > >  src/cpu/cpu_map.xml | 11 +++++++++++
> > > >  1 file changed, 11 insertions(+)
> > > >
> > > > diff --git a/src/cpu/cpu_map.xml b/src/cpu/cpu_map.xml index
> > > > 08aded2..2e2cb4f 100644
> > > > --- a/src/cpu/cpu_map.xml
> > > > +++ b/src/cpu/cpu_map.xml
> > > > @@ -320,6 +320,9 @@
> > > >      <feature name='rtm'>
> > > >        <cpuid function='0x00000007' ebx='0x00000800'/>
> > > >      </feature>
> > > > +    <feature name='cmt'>
> > > > +      <cpuid function='0x00000007' ebx='0x00001000'/>
> > > > +    </feature>
> > > >      <feature name='mpx'>
> > > >        <cpuid function='0x00000007' ebx='0x00004000'/>
> > > >      </feature>
> > >
> > > This hunk won't apply since about a week ago. Please, use current
> > > git when sending patches.
> > >
> > > > @@ -353,6 +356,14 @@
> > > >        <cpuid function='0x80000007' edx='0x00000100'/>
> > > >      </feature>
> > > >
> > > > +    <!-- cpuid level 0x0000000f:1 (edx) -->
> > > > +    <feature name='mbm_total'> <!-- LLC Total MBM monitoring -->
> > > > +      <cpuid function='0x0000000f' edx='0x00000002'/>
> > > > +    </feature>
> > > > +    <feature name='mbm_local'> <!-- LLC Local MBM monitoring -->
> > > > +      <cpuid function='0x0000000f' edx='0x00000004'/>
> > > > +    </feature>
> > > > +
> > >
> > > And keep the list of features sorted by CPUID level, i.e., these
> > > features should go after 0x0d and before 0x80000000.
> >
> > Oh and I completely forgot the most important thing: it makes little
> > sense to add CPUID features that QEMU does not support. It will only
> > allow users to see the features in host CPU capabilities. So if the
> > purpose of these patches is to be able to advertise whether the
> > appropriate perf events are supported on current host, CPU features
> > are not the right way of doing that. I think domain capabilities XML
> > would be the right place to advertise what events are supported.
> 
> Nova schedules guests based on the CPU features that the host has, so we really
> do want this to be exposed in the general host capabilities XML description of
> the host CPU. We don't care about running guests with this features - we just
> want to see the host report for them.
> 
> 

Yes, Nova need host report for these features, and I will submit new version for this patch based on latest code according to Jiri's previous comment.

Thanks,
Qiaowei