From: David Miller <davem@davemloft.net>
To: netdev@vger.kernel.org
Cc: david.stevens@oracle.com, Raghuram.Kothakota@oracle.com,
sowmini.varadhan@oracle.com
Subject: sunvnet and ->xmit_more
Date: Tue, 07 Oct 2014 15:18:49 -0400 (EDT) [thread overview]
Message-ID: <20141007.151849.84417269004453869.davem@davemloft.net> (raw)
David and others working on sunvnet, I just wanted to point out that
in the net-next tree there is a new facility that can improve
performance quite a bit in sunvnet.
Basically in the ->ndo_start_xmit() handler, if you see skb->xmit_more
set then the stack is telling you that it guarentees that another
packet will be given to you immediately when ->ndo_start_xmit()
returns.
This means that, unless you have filled up your TX queue, you can
defer the TX indication to the device.
For example, in the virtio_net driver the test is:
if (__netif_subqueue_stopped(dev, qnum) || !skb->xmit_more)
virtqueue_kick(sq->vq);
The pktgen module also has a new "burst" parameter you can use to test
out this facility directly, and the qdisc layer has heuristics for
dequeueing multiple packets at a time for normal traffic.
Just FYI...
next reply other threads:[~2014-10-07 19:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-07 19:18 David Miller [this message]
2014-10-07 19:29 ` sunvnet and ->xmit_more Sowmini Varadhan
2014-10-07 19:38 ` David Miller
2014-10-07 20:38 ` Raghuram Kothakota
2014-10-07 20:46 ` David Miller
2014-10-07 20:51 ` Sowmini Varadhan
[not found] ` <CACP96tSqmPzwYQKbAfVFc2YmyEOdyRtxeoCSuczx1EZTrF0JMA@mail.gmail.com>
2014-10-08 23:51 ` Sowmini Varadhan
2014-10-07 20:22 ` David L Stevens
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