On 17/02/2015 16:02, Igor Mammedov wrote:

quoted

quoted

Not if there are about 6 regions, I think.

When memslots where increased to 509 and look up of them was replaced on
binary search results were on par with linear search for a default 13 memslots VM.

Adding LRU

You mean MRU. :)

cache helped to shave ~40% of cycles for sequential lookup workloads.

It's a bit different for vhost because you can have up to four "things"
being looked up at the same time:

- the s/g list that will end up in the skb

- the avail/used ring

- the virtio buffers

- the virtio indirect buffers

So you probably need multiple MRU caches.  But yes, MRU can help a lot.

Paolo