[libvirt] [PATCH V2 1/9] qemu_migration: Add support for mutil-thread compressed migration enable

[Jiri Denemark]

On Sat, Nov 07, 2015 at 15:06:03 +0000, Feng, Shaohe wrote:
> 
> > However, since we already have VIR_MIGRATE_COMPRESSED flag and I can imagine various other hypervisors could support
> > their own compression methods, I think using flags for selecting the compression method is wrong. So what if we keep just
> > VIR_MIGRATE_COMPRESSED flag and introduce a new migration parameter to let the user select what compression method
> > they want to use (XBZRLE, multithreaded compression, ...) and each of them could be further configurable with additional
> > parameters. Each hypervisor would also advertise a list of supported compression methods via
> > virConnectGetDomainCapabilities. QEMU would have XBZRLE method selected by default for backward compatibility (it would
> > have to be advertised as the default method in virConnectGetDomainCapabilities too).
> >
> 
> Hi, Jiri.
> 
> I have check the domcapabilities.
> There is no any compression info from domcapabilities.
> 
> Do you means we need to add a new element of domainCapabilities as follow:
> <domainCapabilities>
>   <migration>
>     < XBZRLE supported='yes'>
>     </ XBZRLE >
>     < mutil-thread supported='yes'>
>       <method >
>         <value>xz</value>
>       </method >
>       <level >
>         <value>8</value>
>       </ level >
>       <compress-counter>
>         <value>4</value>
>       </ compress-counter >
>       <decompress-counter>
>         <value>2</value>
>       </decompress-counter >
>     </ mutil-thread >
>   </ migration >
> </domainCapabilities>

In general yes, but I was thinking about a bit different schema:

<domcapabilities>
  ...
  <migration>
    <compression>
      <method name='xbzrle' default='yes'>
        <param name='cache'/>
      </method>
      <method name='mt'>
        <param name='level'/>
        <param name='threads'/>
        <param name='dthreads'/>
      </method>
      ...
    </compression>
  </migration>
</domcapabilities>

Jirka