[ovs-dev] [PATCH] netdev-dpdk: Change eth rx burst size.

[Pravin Shelar]

On Thu, Apr 9, 2015 at 2:36 PM, Traynor, Kevin <kevin.traynor at intel.com> wrote:
>
>> -----Original Message-----
>> From: Pravin Shelar [mailto:pshelar at nicira.com]
>> Sent: Thursday, April 9, 2015 9:10 PM
>> To: Traynor, Kevin; Daniele Di Proietto
>> Cc: dev at openvswitch.org
>> Subject: Re: [ovs-dev] [PATCH] netdev-dpdk: Change eth rx burst size.
>>
>> On Wed, Apr 8, 2015 at 8:43 AM, Kevin Traynor <kevin.traynor at intel.com>
>> wrote:
>> > Change eth rx burst size from 192 to 32. This significantly
>> > improves performance for packets that will be forwarded
>> > through dpdkvhost ports, as the max dpdkvhost tx burst
>> > size (32) will not be exceeded. There are negligible
>> > effects in other scenarios.
>> >
>> > Signed-off-by: Kevin Traynor <kevin.traynor at intel.com>
>>
>> Daniele,
>> You mentioned that you are going to fix the issue by handling
>> different burst size of vhost devices. Do you have the fix?
>
> It wasn't clear in the commit message but just to clarify, the
> dpdkvhost max burst size is set in the DPDK vhost library and if
> we try and enqueue >32 packets only 32 will be enqueued. We can
> add a back-off/retry but it will give better performance to
> ensure that the vhost burst size is not exceeded.
>

How about adding for loop in vhost_send() to handle burst of packets
larger than 32?