netdev - Re: [net-next PATCH 2/3] qdisc: bulk dequeue support for qdiscs with TCQ_F

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Date:	Tue, 02 Sep 2014 08:22:42 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Jesper Dangaard Brouer <brouer@...hat.com>
Cc:	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
	Florian Westphal <fw@...len.de>,
	Hannes Frederic Sowa <hannes@...essinduktion.org>,
	Daniel Borkmann <dborkman@...hat.com>
Subject: Re: [net-next PATCH 2/3] qdisc: bulk dequeue support for qdiscs
 with TCQ_F_ONETXQUEUE

On Tue, 2014-09-02 at 16:35 +0200, Jesper Dangaard Brouer wrote:

> This is crazy fast. This measurement is actually "too-high" as
> 10Gbit/s wirespeed is 14,880,952 (11049 pps too fast).
> 
> Signed-off-by: Jesper Dangaard Brouer <brouer@...hat.com>
> ---

This looks buggy, you forgot about GSO.

(You did the test only for first dequeued packet, not the followings)

Make sure you test your patch with something else than pktgen.

Also, our idea was to use a byte count limit (aka BQL)

If we dequeue 8 64KB packets, this patch adds head of line blocking,
which we fought hard.



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