Avi Kivity wrote: > David S. Ahern wrote: >> Avi: >> >> We did not get a chance to do this at the Forum. I'd be interested in >> whatever options you have for reducing the scan time further (e.g., try >> to get scan time down to 1-2 seconds). >> >> > > I'm unlikely to get time to do this properly for at least a week, as > this will be quite difficult and I'm already horribly backlogged. > However there's an alternative option, modifying the source and getting > it upstreamed, as I think RHEL 3 is still maintained. > > The attached patch (untested) should give a 3X boost for kmap_atomics, > by folding the two accesses to set the pte into one, and by dropping the > access that clears the pte. Unfortunately it breaks the ABI, since > external modules will inline the original kmap_atomic() which expects > the pte to be cleared. > > This can be worked around by allocating new fixmap slots for kmap_atomic > with the new behavior, and keeping the old slots with the old behavior, > but we should first see if the maintainers are open to performance > optimizations targeting kvm. > RHEL3 is in Maintenance mode (for an explanation see http://www.redhat.com/security/updates/errata/) which means performance enhancement patches will not make it in.
Also, I'm going to be out of the office for a couple of weeks in July, so I will need to put this aside until mid-August or so. I'll reevaluate options then. david -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
