Anthony Liguori wrote: > Avi Kivity wrote: >> Anthony Liguori wrote: >>> Howdy, >>> >>> Does anyone know what the state of a pv_ops backend for KVM is? I >>> know Ingo has an implementation that implements CR3 caching but I >>> don't see any branches in Avi's git tree. >>> >>> Perhaps we should try for a simple pv_ops backend for 2.6.23 seeing >>> as how the host infrastructure is there? I'd be willing to do some >>> leg work here... >> >> I think we should aim for a full direct paging implementation, where >> the cr3 cache is just the cherry on top that makes context switches >> proceed at native speed. Jun has a paper on it for OLS and I hope >> patches too. > > That's a bit more ambitious than I was thinking. I would be very > happy with a pv timer, interrupt controller, and some basic CPU > optimizations. I'm still not convinced the perf benefits of direct > paging justify the annoyances that come with it (guests being aware of > pfns).
I thought that with paravirt_ops, all the awareness is limited to the paravirt implementation, and nothing in the core kernel is actually aware of host pfns. pv timer and interrupt controller make a lot of sense, especially if steal timer functionality is included. > This is especially true with NPT/EPT right around the corner. It depends on the workload. It was advanced (by Ingo) that NPT/EPT increase the tlb miss latency, which is important for steady-state workloads, whereas shadow and direct paging do not. It will be interesting to measure this. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
