On 05/03/2012 03:09 PM, Xiao Guangrong wrote: > Actually, the improvement of lockless is that it can let vcpu to be parallel > as possible. > > From the test result, lockless gains little improvement for unix-migration, > in this case, the vcpus are almost idle (at least not busy). > > The large improvement is from dbench-migration, in this case, all vcpus are > busy accessing memory which is write-protected by dirty-log. If you enable > page-fault/fast-page-fault tracepoints, you can see huge number of page fault > from different vcpu during the migration. > We can kill the page faults completely by using A/D bits in shadow page tables. The latest version of the Intel SDM defines A/D bits for EPT, and NPT has had them from day one. Of course this comes at a cost, instead of traversing a bitmap we have to read all sptes, which are 64x as large. But it's probably worthwhile for large guests and perhaps also for smaller ones. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
