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From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
	Olivier MATZ <olivier.matz@6wind.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH RFC 11/11] ixgbe/mbuf: add TSO support
Date: Mon, 19 May 2014 14:32:59 +0200	[thread overview]
Message-ID: <1734202.xbDzyIthla@xps13> (raw)
In-Reply-To: <2601191342CEEE43887BDE71AB9772580EFA6ED5@IRSMSX105.ger.corp.intel.com>

Hi,

I'll try so sum it up this interesting discussion about checksum API for TSO.

We know at least 2 checksum methods:
- the standard one
- the special one for ixgbe TSO
In Linux ixgbe, checksum is redone in the driver for TSO case.

We want to compute checksum in the application/stack in order to prevent 
driver from modifying packet data, that could cause cache miss.
But the application cannot always know which checksum method to use because it 
doesn't have to know which driver will process the packet.
So we have to choose which checksum method can be done in the application 
without driver processing. It's not an easy choice.

It seems simpler and reasonnable to choose the standard pseudo-header checksum 
method as it is done in Linux.
Having a stable and generic API is something important we must target.

Thanks
-- 
Thomas

  reply	other threads:[~2014-05-19 12:32 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-09 14:50 [dpdk-dev] [PATCH RFC 00/11] " Olivier Matz
2014-05-09 14:50 ` [dpdk-dev] [PATCH RFC 01/11] igb/ixgbe: fix IP checksum calculation Olivier Matz
2014-05-15 10:40   ` Ananyev, Konstantin
2014-05-09 14:50 ` [dpdk-dev] [PATCH RFC 02/11] mbuf: rename RTE_MBUF_SCATTER_GATHER into RTE_MBUF_REFCNT Olivier Matz
2014-05-09 14:50 ` [dpdk-dev] [PATCH RFC 03/11] mbuf: remove rte_ctrlmbuf Olivier Matz
2014-05-25 21:39   ` Gilmore, Walter E
2014-05-26 12:23     ` Olivier MATZ
2014-05-26 16:40     ` Dumitrescu, Cristian
2014-05-26 22:43     ` Neil Horman
2014-05-27  0:17   ` Stephen Hemminger
2014-05-28  9:45     ` Ananyev, Konstantin
2014-05-09 14:50 ` [dpdk-dev] [PATCH RFC 04/11] mbuf: remove the rte_pktmbuf structure Olivier Matz
2014-05-09 14:50 ` [dpdk-dev] [PATCH RFC 05/11] mbuf: merge physaddr and buf_len in a bitfield Olivier Matz
2014-05-09 15:39   ` Shaw, Jeffrey B
2014-05-09 16:06     ` Olivier MATZ
2014-05-09 16:11       ` Shaw, Jeffrey B
2014-05-14 14:07         ` Ananyev, Konstantin
2014-05-15  9:53           ` Olivier MATZ
2014-05-19  7:27         ` Olivier MATZ
2014-05-19  8:25           ` Richardson, Bruce
2014-05-19  9:30             ` Olivier MATZ
2014-05-19  9:57               ` Richardson, Bruce
2014-05-09 14:50 ` [dpdk-dev] [PATCH RFC 06/11] mbuf: replace data pointer by an offset Olivier Matz
2014-05-12 14:12   ` Thomas Monjalon
2014-05-12 14:36     ` Venkatesan, Venky
2014-05-12 14:41       ` Neil Horman
2014-05-12 15:07         ` Olivier MATZ
2014-05-12 15:59           ` Stephen Hemminger
2014-05-12 16:13             ` Olivier MATZ
2014-05-12 17:13               ` Stephen Hemminger
2014-05-13 13:29                 ` Olivier MATZ
2014-05-12 16:06           ` Venkatesan, Venky
2014-05-12 18:39             ` Neil Horman
2014-05-13 13:54               ` Venkatesan, Venky
2014-05-13 14:09                 ` Thomas Monjalon
2014-05-09 14:50 ` [dpdk-dev] [PATCH RFC 07/11] mbuf: add functions to get the name of an ol_flag Olivier Matz
2014-05-09 14:50 ` [dpdk-dev] [PATCH RFC 08/11] mbuf: change ol_flags to 32 bits Olivier Matz
2014-05-09 14:50 ` [dpdk-dev] [PATCH RFC 09/11] mbuf: rename vlan_macip_len in hw_offload and increase its size Olivier Matz
2014-05-09 14:50 ` [dpdk-dev] [PATCH RFC 10/11] testpmd: modify source address to validate checksum calculation Olivier Matz
2014-05-09 14:50 ` [dpdk-dev] [PATCH RFC 11/11] ixgbe/mbuf: add TSO support Olivier Matz
2014-05-12 14:30   ` Thomas Monjalon
2014-05-15 15:09   ` Ananyev, Konstantin
2014-05-15 15:39     ` Olivier MATZ
2014-05-15 16:30       ` Ananyev, Konstantin
2014-05-16 12:11         ` Olivier MATZ
2014-05-16 17:01           ` Ananyev, Konstantin
2014-05-19 12:32             ` Thomas Monjalon [this message]
2014-05-09 17:04 ` [dpdk-dev] [PATCH RFC 00/11] " Stephen Hemminger
2014-05-09 21:49   ` Olivier MATZ
2014-05-10  0:39     ` Stephen Hemminger
2014-05-19 12:47 ` Thomas Monjalon

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