[ovs-dev] [PATCH] ofproto: fix interactions between flow monitors and barriers

Ben Pfaff blp at nicira.com
Tue Feb 11 20:35:10 UTC 2014

On Wed, Feb 05, 2014 at 07:04:05PM +0900, YAMAMOTO Takashi wrote:
> Following OpenFlow 1.4 semantics, make barriers wait for
> flow monitor replies.  This should fix a race in
> "ofproto - flow monitoring pause and resume" test.
> Signed-off-by: YAMAMOTO Takashi <yamamoto at valinux.co.jp>

I still don't understand this.  You cite the following:

     * OpenFlow 1.4.0 p.110:
     *    A OFPMP_FLOW_MONITOR multipart reply can not cross a barrier
     *    handshake.  The switch must always send the OFPMP_FLOW_MONITOR
     *    multipart reply for a given flow table change before the reply
     *    to a OFPT_BARRIER_REQUEST request that follows the request
     *    responsible for the flow table change.

but can you elaborate on your thought process here?  After all, when
we're paused we're not sending any flow table changes at all.

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