Hi, On 09/09/2016 05:39 AM, Zhihong Wang wrote: > This patch set optimizes the vhost enqueue function. > > It implements the vhost logic from scratch into a single function designed > for high performance and good maintainability, and improves CPU efficiency > significantly by optimizing cache access, which means: > > * Higher maximum throughput can be achieved for fast frontends like DPDK > virtio pmd. > > * Better scalability can be achieved that each vhost core can support > more connections because it takes less cycles to handle each single > frontend. > > This patch set contains: > > 1. A Windows VM compatibility fix for vhost enqueue in 16.07 release. > > 2. A baseline patch to rewrite the vhost logic. > > 3. A series of optimization patches added upon the baseline. > > The main optimization techniques are: > > 1. Reorder code to reduce CPU pipeline stall cycles. > > 2. Batch update the used ring for better efficiency. > > 3. Prefetch descriptor to hide cache latency. > > 4. Remove useless volatile attribute to allow compiler optimization. > > Code reordering and batch used ring update bring most of the performance > improvements. > > In the existing code there're 2 callbacks for vhost enqueue: > > * virtio_dev_merge_rx for mrg_rxbuf turned on cases. > > * virtio_dev_rx for mrg_rxbuf turned off cases. > > The performance of the existing code is not optimal, especially when the > mrg_rxbuf feature turned on. Besides, having 2 callback paths increases > maintenance efforts. > > Also, there's a compatibility issue in the existing code which causes > Windows VM to hang when the mrg_rxbuf feature turned on. > > --- > Changes in v5: > > 1. Rebase to the latest branch. > > 2. Rename variables to keep consistent in naming style. > > 3. Small changes like return value adjustment and vertical alignment. > > 4. Add details in commit log. Just tried to apply your series without success. Apparently, it is not based directly on master branch, as it lacks some SHA-1 information.
Could you rebase it against master please? Thanks, Maxime
