Messages in this thread | | | Date | Thu, 12 May 2011 15:43:40 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH v1 0/5] KVM in-guest performance monitoring |
| |
On Thu, May 12, 2011 at 03:23:39PM +0200, Jan Kiszka wrote: > On 2011-05-12 15:11, Joerg Roedel wrote:
> > Seriously, I think such decisions should be technical only and not > > political like that. The losers of such political decisions are always > > the users because they don't get useful features that are technical > > possible. > > Paravirt remains a workaround, useful until hardware provides a solution > for all guests, and that often in an even more efficient way (like for > MMU virtualization).
Fully agreed. And todays x86 CPUs lack proper support for virtualizing the PMU. That will hopefully change but users want the feature today.
> We do not need to block a PV-PMU for Linux guests (or other OSes that > want to adopt to it), but that will not be a solution for the problem, > that's my point. A PV-PMU may even be useful to demonstrate usefulness > of a virtual PMU the CPU vendors (if they aren't aware of this yet).
Right, if users actually use the virtual PMU this probably increases the priority for proper hardware support.
Joerg
| |