On 05/20/2010 01:27 AM, Michael S. Tsirkin wrote: > On Wed, May 19, 2010 at 08:04:51PM +0300, Avi Kivity wrote: > >> On 05/18/2010 04:19 AM, Michael S. Tsirkin wrote: >> >>> With PUBLISH_USED_IDX, guest tells us which used entries >>> it has consumed. This can be used to reduce the number >>> of interrupts: after we write a used entry, if the guest has not yet >>> consumed the previous entry, or if the guest has already consumed the >>> new entry, we do not need to interrupt. >>> This imporves bandwidth by 30% under some workflows. >>> >>> Signed-off-by: Michael S. Tsirkin<mst@xxxxxxxxxx> >>> --- >>> >>> Rusty, Dave, this patch depends on the patch >>> "virtio: put last seen used index into ring itself" >>> which is currently destined at Rusty's tree. >>> Rusty, if you are taking that one for 2.6.35, please >>> take this one as well. >>> Dave, any objections? >>> >>> >> I object: I think the index should have its own cacheline, >> > The issue here is that host/guest do not know each > other's cache line size. I guess we could just put it > at offset 128 or something like that ... Rusty? > Not so pretty, but ok. > >> and that it should be documented before merging. >> > I think you meant to object to the virtio patch, not this one. This > patch does not introduce new layout, just implements host support. > virtio spec patch will follow: it is not part of linux tree so > there is no patch dependency. > There is a reviewer dependency. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
