Messages in this thread | | | Date | Mon, 28 Feb 2011 11:55:01 -0500 | From | "John W. Linville" <> | Subject | Re: txqueuelen has wrong units; should be time |
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On Mon, Feb 28, 2011 at 05:48:14PM +0100, Eric Dumazet wrote: > Le lundi 28 février 2011 à 11:11 -0500, John W. Linville a écrit : > > On Sun, Feb 27, 2011 at 09:07:53PM +0100, Eric Dumazet wrote: > > > > > Qdisc should return to caller a good indication packet is queued or > > > dropped at enqueue() time... not later (aka : never) > > > > > > Accepting a packet at t0, and dropping it later at t0+limit without > > > giving any indication to caller is a problem. > > > > Can you elaborate on what problem this causes? Is it any worse than > > if the packet is dropped at some later hop? > > > > Is there any API that could report the drop to the sender (at > > least a local one) without having to wait for the ack timeout? > > Should there be? > > > > Not all protocols have ACKS ;) > > dev_queue_xmit() returns an error code, some callers use it.
Well, OK -- I agree it is best if you can return the status at enqueue time. The question becomes whether or not a dropped frame is worse than living with high latency. The answer, of course, still seems to be a bit subjective. But, if the admin has determined that a link should be low latency...?
John -- John W. Linville Someday the world will need a hero, and you linville@tuxdriver.com might be all we have. Be ready. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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