[dpdk-dev] [PATCH v3 0/7] virtio_user as an alternative exception path
jianfeng.tan at intel.com
Tue Jan 10 09:46:02 CET 2017
On 1/9/2017 10:06 PM, Bruce Richardson wrote:
> On Wed, Jan 04, 2017 at 03:59:19AM +0000, Jianfeng Tan wrote:
>> - Drop the patch to postpone driver ok sending patch, superseded it
>> with a bug fix to disable all virtqueues and re-init the device.
>> (you might wonder why not just send reset owner msg. Under my test,
>> it causes spinlock deadlock problem when killing the program).
>> - Avoid compiling error on 32-bit system for pointer convert.
>> - Fix a bug in patch "abstract virtio user backend ops", vhostfd is
>> not properly assigned.
>> - Fix a "MQ cannot be used" bug in v2, which is related to strip
>> some feature bits that vhost kernel does not recognize.
>> - Update release note.
>> v2: (Lots of them are from yuanhan's comment)
>> - Add offloding feature.
>> - Add multiqueue support.
>> - Add a new patch to postpone the sending of driver ok notification.
>> - Put fix patch ahead of the whole patch series.
>> - Split original 0001 patch into 0003 and 0004 patches.
>> - Remove the original vhost_internal design, just add those into
>> struct virtio_user_dev for simplicity.
>> - Reword "control" to "send_request".
>> - Reword "host_features" to "device_features".
>> In v16.07, we upstreamed a virtual device, virtio_user (with vhost-user
>> as the backend). The path to go with a vhost-kernel backend has been
>> dropped for bad performance comparing to vhost-user and code simplicity.
>> But after a second thought, virtio_user + vhost-kernel is a good
>> candidate as an exceptional path, such as KNI, which exchanges packets
>> with kernel networking stack.
>> - maintenance: vhost-net (kernel) is upstreamed and extensively used
>> kernel module. We don't need any out-of-tree module like KNI.
>> - performance: as with KNI, this solution would use one or more
>> kthreads to send/receive packets from user space DPDK applications,
>> which has little impact on user space polling thread (except that
>> it might enter into kernel space to wake up those kthreads if
>> - features: vhost-net is born to be a networking solution, which has
>> lots of networking related featuers, like multi queue, tso, multi-seg
>> mbuf, etc.
>> Signed-off-by: Jianfeng Tan <jianfeng.tan at intel.com>
> Sounds great. However, I think we'll need a how-to doc for this to help
> people get it up and running as a KNI replacement for packets to/from
> the kernel. Any plans to draw up such a doc? It would be good to include
> it in this patchset.
I was planning to do that in separate patchset. But I agree with you
that it's better to do that in this patchset.
More information about the dev