Re: [dpdk-dev] [RFC PATCH] vhost: remove lockless enqueue to virt ring

[Tetsuya Mukawa <mukawa@igel.co.jp>]

On 2015/11/05 19:21, Xie, Huawei wrote:
> If no objections, would remove the internal cmpset enqueue, should get
> some improved performance.
>
> No idea why commit message is lost:
> DPDK doesn't support receiving/transmitting packets from/to the same
> port/queue.
> Vhost pmd wraps vhost device as normal dpdk port. dpdkvhost based
> applications/switch
>  also treate virtio port and physical port both as ports, and have
> their  own
> lock implmentation when to enqueue packets to the same port. This patch
> removes
> the internal lockless vhost enqueue implmentation.
> On 11/5/2015 5:38 PM, Huawei Xie wrote:
>> Signed-off-by: Huawei Xie <huawei.xie@intel.com>

Hi Xie,

I think it's a good optimization.
But I  guess the patch will changes behavior of vhost library API.
For example, if someone has already implemented an application based on
the assumption that vhost library has internal lock, I doubt their
application will face an issue with this patch.

If it's correct, we might need to follow below steps.
http://dpdk.org/doc/guides/contributing/versioning.html

Thanks,
Tetsuya