On Tue, 2011-02-22 at 16:25 +0200, Avi Kivity wrote: > On 02/22/2011 10:12 AM, Xiao Guangrong wrote: > > Sort memslots then search the slot with binary search to speed up the > > slot searching > > > > I'm not sure if a binary search is the right algorithm here. It > introduces a lot of branches which may be mispredicted. > > Options we've discussed are: > > - Sort slots by size, use linear search (so the largest slots are found > quickly) > - Weighted balanced tree > http://en.wikipedia.org/wiki/Weight-balanced_tree, use weight == slot size I've got an implementation using a weight balanced tree working now. I need to do some testing to see if I can detect any performance difference from the current unsorted, linear array. > Both options still make the miss case (mmio) slow. We could cache the > result of a miss in an spte by using a reserved bit, and checking the > page fault error code (or seeing if we get an ept violation or ept > misconfiguration), so if we get repeated mmio on a page, we don't need > to search the slot list/tree. I haven't started on this idea yet. Thanks, Alex -- 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
