From: David Miller <davem@davemloft.net>
To: kys@microsoft.com
Cc: eric.dumazet@gmail.com, haiyangz@microsoft.com,
edumazet@google.com, netdev@vger.kernel.org
Subject: Re: [PATCH net-next] net: increase LL_MAX_HEADER if HYPERV_NET is enabled
Date: Tue, 03 Nov 2015 10:33:19 -0500 (EST) [thread overview]
Message-ID: <20151103.103319.1465681990237533576.davem@davemloft.net> (raw)
In-Reply-To: <BY2PR0301MB16547E3AA4FB1F1AC8DE28ECA02B0@BY2PR0301MB1654.namprd03.prod.outlook.com>
From: KY Srinivasan <kys@microsoft.com>
Date: Tue, 3 Nov 2015 07:59:36 +0000
> I have implemented the scheme we had discussed a few weeks ago. In
> this new implementation our driver is NOT requesting addition
> headroom - rndis header and the per packet state is being maintained
> outside of the skb. What I am seeing is that when I have
> LL_MAX_HEADER set to 220 bytes, even though our driver is not using
> the additional head room, I see about a 10% boost in the peak
> performance (about 34 Gbps on a 40Gbps interface). However, when I
> set the LL_MAX_HEADER value to the current default, the peak
> performance drops back to what we currently have (around 31
> Gbps). In both these cases, there is no reallocation of skb since no
> additional headroom is being requested and yet there is a
> significant difference in performance. I trying to figure out why
> this is the case, your insights will be greatly appreciated.
It probably has something to do with cache line or data alignment.
next prev parent reply other threads:[~2015-11-03 15:33 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-29 21:49 [patch] tcp: attach SYNACK messages to request sockets instead of listener Haiyang Zhang
2015-10-29 22:58 ` Eric Dumazet
2015-10-30 19:38 ` Haiyang Zhang
2015-10-30 20:02 ` Eric Dumazet
2015-10-30 20:18 ` Eric Dumazet
2015-10-30 21:42 ` Haiyang Zhang
2015-10-30 23:52 ` Eric Dumazet
2015-11-01 17:20 ` [PATCH net-next] net: increase LL_MAX_HEADER if HYPERV_NET is enabled Eric Dumazet
2015-11-01 20:58 ` David Miller
2015-11-01 22:36 ` Eric Dumazet
2015-11-01 22:58 ` [PATCH net-next] net: make skb_set_owner_w() more robust Eric Dumazet
2015-11-01 23:18 ` kbuild test robot
2015-11-01 23:27 ` Eric Dumazet
2015-11-01 23:36 ` [PATCH v2 " Eric Dumazet
2015-11-02 20:05 ` Haiyang Zhang
2015-11-02 20:09 ` Eric Dumazet
2015-11-02 20:26 ` David Miller
2015-11-02 21:29 ` David Miller
2015-11-03 7:59 ` [PATCH net-next] net: increase LL_MAX_HEADER if HYPERV_NET is enabled KY Srinivasan
2015-11-03 15:33 ` David Miller [this message]
2015-11-03 16:37 ` Eric Dumazet
2015-11-03 17:34 ` Haiyang Zhang
2015-11-03 18:20 ` David Miller
2015-11-03 18:49 ` Haiyang Zhang
2015-11-03 19:50 ` David Miller
2015-11-03 21:00 ` Haiyang Zhang
2015-11-03 18:09 ` KY Srinivasan
2015-10-30 20:28 ` [patch] tcp: attach SYNACK messages to request sockets instead of listener KY Srinivasan
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