[ovs-dev] [PATCH v2] dpif: allow adding ukeys for same flow by different pmds

Ilya Maximets i.maximets at samsung.com
Fri Jan 29 12:03:31 UTC 2016


Hi.

On 29.01.2016 04:02, Daniele Di Proietto wrote:
> Hi guys,
> 
> Sorry for resurrecting this thread, but I think we should reconsider
> this patch at this point.
> 
> Let me explain: I'm still perfectly happy with the fix we applied,
> e4e74c3a2b9a("dpif-netdev: Purge all ukeys when reconfigure pmd."),
> it is necessary to properly collect stats and it works perfectly
> when reconfiguring pmd threads.
> 
> I'm revisiting this, because I'm not that comfortable anymore assuming
> that packets with the exact same flow have to come in from the
> same queue.  Here's a couple of scenarios:
> 
> - With vhost-user multi queue, I'm not sure that anything prevents a
>   guest from sending the same flow to different queues.

Nothing prevents. That is true. But this situation isn't really clear.
Can you imagine situation where normal application in normal mode
sends same flow to different queues and expects no issues?

> - We've encountered the same bug in dpif-netdev when adding/removing
>   ports.  We fixed it by never moving the queues from the original
>   pmd thread, which makes sense, but that's just an example
> - At some point it would be nice to reassign queues among pmd threads
>   without deleting the megaflow cache.

I agree that this two scenarios can be useful. I want to implement
some kind of scheduler for pmd threads to manage port/rxqs assignment.
In this case ability to reassign queues without destroying of threads
will be very nice.

Best regards, Ilya Maximets.



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