Re: [dpdk-dev] [ [PATCH v2] 01/13] virtio: Introduce config RTE_VIRTIO_INC_VECTOR

[Stephen Hemminger <stephen@networkplumber.org>]

On Fri, 18 Dec 2015 09:52:29 +0000
"Xie, Huawei" <huawei.xie@intel.com> wrote:

> > low level SSE bit twiddling.  
> Hi Stephen:
> We only did SSE twiddling to RX, which almost doubles the performance
> comparing to normal path in virtio/vhost performance test case. Indirect
> and any layout feature enabling are mostly for TX. We also did some
> optimization for single segment and non-offload case in TX, without
> using SSE, which also gives ~60% performance improvement, in Qian's
> result. My optimization is mostly for single segment and non-offload
> case, which i calls simple rx/tx.
> I plan to add virtio/vhost performance benchmark so that we could easily
> measure the performance difference for each patch.
> 
> Indirect and any layout features are useful for multiple segment
> transmitted packet mbufs. I had acked your patch at the first time, and
> thought it is applied. I don't understand why you say it is ignored by
> Intel.

Sorry, did not mean to blame Intel, ... more that why didn't it get in 2.2?

It turns out any layout/indirect helps all transmits because they can then
take a single tx descriptor rather than multiple.