Re: [libvirt] [RFC PATCH 0/2] Introduce RDT memory bandwidth allocation support

Hi Pavel, On 2018年06月06日 13:56, bing.niu wrote: > > > > Then there is the domain XML, for CAT we use this: > > > > <domain> > >    ... > >    <cputune> > >      ... > >      <cachetune vcpus='0-3'> > >        <cache id='0' level='3' type='both' size='3' unit='MiB'/> > >        <cache id='1' level='3' type='both' size='3' unit='MiB'/> > >      </cachetune> > >      ... > >    <cputune> > >    ... > > </domain> > > > > so the possible domain XML could look like this: > > > > <domain> > >    ... > >    <cputune> > >      ... > >      <memory vcpus='0-3'> > >        <socket id='0' bandwidth='30'/> > >        <socket id='1' bandwidth='20'/> > >      </memory> > >      ... > >    <cputune> > >    ... > > </domain> > > > > Again, the element names 'memory' and 'socket' can be named differently. > socket --> node? > > Since the existing virrestrl implementation only care about cache part > during development, So we may need change some names of structure and > functions when enable MBA. How do you think > > > > Pavel > > > Is that possible to support MBA by extending CAT in domain XML? Since each <cachetune> will map to one virresctrlalloc structure and create a rdt_group in resctrl fs. Each rdt_group will have it's own closid. this work perfect if CAT only available. However, if MBA coming in with CAT enabled also, ike this. <domain> ... <cputune> ... <cachetune vcpus='0-3'> <cache id='0' level='3' type='both' size='3' unit='MiB'/> <cache id='1' level='3' type='both' size='3' unit='MiB'/> </cachetune> <memory vcpus='2-3'> <socket id='0' bandwidth='30'/> <socket id='1' bandwidth='20'/> </memory> ... <cputune> ... </domain> we have to make sure those two allocating will not have vcpu overlapped. like this, if (virBitmapOverlaps(def->cachetunes[i]->vcpus, vcpus) || virBitmapOverlaps(def->memroy->vcpus, vcpus)) { virReportError(VIR_ERR_XML_ERROR, "%s", _("Overlapping vcpus in cachetunes")); goto cleanup; that looks like introducing some dependency between CAT and MBA. Is that possible we rename cachetune so that handle CAT MBA together one section?