From: David Miller <davem@davemloft.net>
To: jasowang@redhat.com
Cc: mst@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
virtualization@lists.linux-foundation.org,
eric.dumazet@gmail.com, brouer@redhat.com
Subject: Re: [PATCH net-next V2] tun: introduce tx skb ring
Date: Thu, 16 Jun 2016 17:01:31 -0700 (PDT) [thread overview]
Message-ID: <20160616.170131.1753206993488742551.davem@davemloft.net> (raw)
In-Reply-To: <1465979897-4445-1-git-send-email-jasowang@redhat.com>
From: Jason Wang <jasowang@redhat.com>
Date: Wed, 15 Jun 2016 16:38:17 +0800
> We used to queue tx packets in sk_receive_queue, this is less
> efficient since it requires spinlocks to synchronize between producer
> and consumer.
>
> This patch tries to address this by:
>
> - introduce a new mode which will be only enabled with IFF_TX_ARRAY
> set and switch from sk_receive_queue to a fixed size of skb
> array with 256 entries in this mode.
> - introduce a new proto_ops peek_len which was used for peeking the
> skb length.
> - implement a tun version of peek_len for vhost_net to use and convert
> vhost_net to use peek_len if possible.
>
> Pktgen test shows about 18% improvement on guest receiving pps for small
> buffers:
>
> Before: ~1220000pps
> After : ~1440000pps
>
> The reason why I stick to new mode is because:
>
> - though resize is supported by skb array, in multiqueue mode, it's
> not easy to recover from a partial success of queue resizing.
> - tx_queue_len is a user visible feature.
>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Michael, can you please review this, especially as this is the first
user of your new infrastructure :-)
next prev parent reply other threads:[~2016-06-17 0:01 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-15 8:38 [PATCH net-next V2] tun: introduce tx skb ring Jason Wang
2016-06-15 10:34 ` kbuild test robot
2016-06-15 11:52 ` Jamal Hadi Salim
2016-06-15 11:55 ` Jamal Hadi Salim
2016-06-16 7:08 ` Jason Wang
2016-06-17 0:01 ` David Miller [this message]
2016-06-17 0:41 ` Michael S. Tsirkin
2016-06-17 7:22 ` Jason Wang
2016-06-22 18:18 ` Michael S. Tsirkin
2016-06-23 5:14 ` Jason Wang
2016-06-28 7:09 ` Michael S. Tsirkin
2016-06-30 1:50 ` Jason Wang
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