>From the source code I found the way to modify n_buffers by adjusting the
PKTBUF_BITS. For example, I can set it to 1024 by setting PKTBUF_BITS to
10.
Does the modification have any some side-effects? Why doesn't OVS make it
adjustable?

/* Buffers are identified by a 32-bit opaque ID.  We divide the ID
>  * into a buffer number (low bits) and a cookie (high bits).  The buffer
> number
>  * is an index into an array of buffers.  The cookie distinguishes between
>  * different packets that have occupied a single buffer.  Thus, the more
>  * buffers we have, the lower-quality the cookie... */
> #define PKTBUF_BITS     8
> #define PKTBUF_MASK     (PKTBUF_CNT - 1)
> #define PKTBUF_CNT      (1u << PKTBUF_BITS)
> #define COOKIE_BITS     (32 - PKTBUF_BITS)
> #define COOKIE_MAX      ((1u << COOKIE_BITS) - 1)


2017-03-16 23:07 GMT+08:00 Ben Pfaff <b...@ovn.org>:

> OVS sends a packet to the controller if the flow table tells it to do
> so.  There's nothing in OpenFlow that restricts this on the basis of a
> flow or a response from the controller.
>
> n_buffers is not adjustable.
>
> On Thu, Mar 16, 2017 at 10:22:38PM +0800, Big Strong wrote:
> > @Ben, does it mean ovs would repeatedly send packet in messages as long
> as
> > no response is got from controller? What will happen when a same packet
> > comes to ovs while the old packet in message is still not handled?
> >
> > Another question, is the n_buffers size adjustable using
> > ovs-ofctl/ovs-vsctl command? I want a larger n_buffers rather than the
> > default 256.
> >
> > Regards.
> >
> > 2017-03-16 4:54 GMT+08:00 Ben Pfaff <b...@ovn.org>:
> >
> > > On Wed, Mar 15, 2017 at 01:34:56PM +0800, yiyefuping198425 wrote:
> > > > I'm asking for assistance to fix this issue: ovs send many packets
> of a
> > > table miss flow instead of the first packet.
> > >
> > > That's how OpenFlow works.
> > > _______________________________________________
> > > discuss mailing list
> > > disc...@openvswitch.org
> > > https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
> > >
>
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