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From: David Miller <davem@davemloft.net>
To: ecree@solarflare.com
Cc: netdev@vger.kernel.org, tom@herbertland.com
Subject: Re: Checksum offload queries
Date: Tue, 08 Dec 2015 12:06:54 -0500 (EST)	[thread overview]
Message-ID: <20151208.120654.2127200076257822677.davem@davemloft.net> (raw)
In-Reply-To: <5666EC4B.40800@solarflare.com>

From: Edward Cree <ecree@solarflare.com>
Date: Tue, 8 Dec 2015 14:42:19 +0000

> I'm afraid I still don't see it.

You assume that nothing in the stack mangles the packet and would
benefit from having the 1's complement to work with in order to
assist with checksum adjustments etc.

So we want 1's complement, all the time.

All of the headers get touched anyways as each layer of the stack
demuxes the packet.  Therefore there is _ZERO_ cost to use 1's
complement to validate checksums in input.

It's always superior.

  parent reply	other threads:[~2015-12-08 17:06 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-07 15:39 Checksum offload queries Edward Cree
2015-12-07 17:29 ` Tom Herbert
2015-12-07 17:52   ` Tom Herbert
2015-12-08 16:03   ` Edward Cree
2015-12-08 16:43     ` Tom Herbert
2015-12-08 18:03       ` Edward Cree
2015-12-08 17:09     ` David Miller
2015-12-08 17:24       ` Edward Cree
2015-12-08 17:28         ` David Miller
2015-12-07 19:38 ` David Miller
2015-12-08 14:42   ` Edward Cree
2015-12-08 17:04     ` Tom Herbert
2015-12-09  1:56       ` Thomas Graf
2015-12-09 16:08         ` Tom Herbert
2015-12-09 22:29           ` Thomas Graf
2015-12-09 22:51             ` Tom Herbert
2015-12-09 23:13               ` Thomas Graf
2015-12-08 17:06     ` David Miller [this message]
2015-12-09 12:14       ` Edward Cree
2015-12-09 16:01         ` Tom Herbert
2015-12-09 17:28           ` Edward Cree
2015-12-09 17:31             ` David Laight
2015-12-09 18:00             ` Tom Herbert
2015-12-09 22:21               ` Thomas Graf
2015-12-09 22:42                 ` Tom Herbert
2015-12-09 22:44                   ` Thomas Graf
2015-12-10 15:49               ` Edward Cree
2015-12-10 16:26                 ` Tom Herbert
2015-12-10 20:28                   ` Edward Cree
2015-12-10 21:02                     ` Rustad, Mark D
2015-12-14 15:11                     ` [RFC PATCH net-next 0/2] Local checksum offload for VXLAN Edward Cree
2015-12-14 15:13                       ` [PATCH 1/2] net: udp: local checksum offload for encapsulation Edward Cree
2015-12-14 17:16                         ` Tom Herbert
2015-12-15 18:07                           ` Edward Cree
2015-12-14 15:13                       ` [PATCH 2/2] net: vxlan: enable local checksum offload on HW_CSUM devices Edward Cree
2015-12-11 23:50             ` Checksum offload queries Tom Herbert
2015-12-12 16:41               ` Sowmini Varadhan
2015-12-12 17:24                 ` Tom Herbert

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