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From: Yongseok Koh <yskoh@mellanox.com>
To: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Cc: Shahaf Shuler <shahafs@mellanox.com>,
	Thomas Monjalon <thomas@monjalon.net>,
	Ferruh Yigit <ferruh.yigit@intel.com>,
	Andrew Rybchenko <arybchenko@solarflare.com>,
	Olivier Matz <olivier.matz@6wind.com>,  dev <dev@dpdk.org>,
	Slava Ovsiienko <viacheslavo@mellanox.com>
Subject: Re: [dpdk-dev] [PATCH] ethdev: add flow tag
Date: Fri, 5 Jul 2019 18:05:50 +0000	[thread overview]
Message-ID: <6EE319CD-4BBC-47BF-AAE5-2165B8C1D491@mellanox.com> (raw)
In-Reply-To: <20190705135404.GR4512@6wind.com>



> On Jul 5, 2019, at 6:54 AM, Adrien Mazarguil <adrien.mazarguil@6wind.com> wrote:
> 
> On Thu, Jul 04, 2019 at 04:23:02PM -0700, Yongseok Koh wrote:
>> A tag is a transient data which can be used during flow match. This can be
>> used to store match result from a previous table so that the same pattern
>> need not be matched again on the next table. Even if outer header is
>> decapsulated on the previous match, the match result can be kept.
>> 
>> Some device expose internal registers of its flow processing pipeline and
>> those registers are quite useful for stateful connection tracking as it
>> keeps status of flow matching. Multiple tags are supported by specifying
>> index.
>> 
>> Example testpmd commands are:
>> 
>>  flow create 0 ingress pattern ... / end
>>    actions set_tag index 2 value 0xaa00bb mask 0xffff00ff /
>>            set_tag index 3 value 0x123456 mask 0xffffff /
>>            vxlan_decap / jump group 1 / end
>> 
>>  flow create 0 ingress pattern ... / end
>>    actions set_tag index 2 value 0xcc00 mask 0xff00 /
>>            set_tag index 3 value 0x123456 mask 0xffffff /
>>            vxlan_decap / jump group 1 / end
>> 
>>  flow create 0 ingress group 1
>>    pattern tag index is 2 value spec 0xaa00bb value mask 0xffff00ff /
>>            eth ... / end
>>    actions ... jump group 2 / end
>> 
>>  flow create 0 ingress group 1
>>    pattern tag index is 2 value spec 0xcc00 value mask 0xff00 /
>>            tag index is 3 value spec 0x123456 value mask 0xffffff /
>>            eth ... / end
>>    actions ... / end
>> 
>>  flow create 0 ingress group 2
>>    pattern tag index is 3 value spec 0x123456 value mask 0xffffff /
>>            eth ... / end
>>    actions ... / end
>> 
>> Signed-off-by: Yongseok Koh <yskoh@mellanox.com>
> 
> Hi Yongseok,
> 
> Only high level questions for now, while it unquestionably looks useful,
> from a user standpoint exposing the separate index seems redundant and not
> necessarily convenient. Using the following example to illustrate:
> 
> actions set_tag index 3 value 0x123456 mask 0xfffff
> 
> pattern tag index is 3 value spec 0x123456 value mask 0xffffff
> 
> I might be missing something, but why isn't this enough:
> 
> pattern tag index is 3 # match whatever is stored at index 3
> 
> Assuming it can work, then why bother with providing value spec/mask on
> set_tag? A flow rule pattern matches something, sets some arbitrary tag to
> be matched by a subsequent flow rule and that's it. It even seems like
> relying on the index only on both occasions is enough for identification.
> 
> Same question for the opposite approach; relying on the value, never
> mentioning the index.
> 
> I'm under the impression that the index is a hardware-specific constraint
> that shouldn't be exposed (especially since it's an 8-bit field). If so, a
> PMD could keep track of used indices without having them exposed through the
> public API.


Thank you for review, Adrien.
Hope you are doing well. It's been long since we talked each other. :-)

Your approach will work too in general but we have a request from customer that
they want to partition this limited tag storage. Assuming that HW exposes 32bit
tags (those are 'registers' in HW pipeline in mlx5 HW). Then, customers want to
store multiple data even in a 32-bit storage. For example, 16bit vlan tag, 8bit
table id and 8bit flow id. As they want to split one 32bit storage, I thought it
is better to provide mask when setting/matching the value. Even some customer
wants to store multiple flags bit by bit like ol_flags. They do want to alter
only partial bits.

And for the index, it is to reference an entry of tags array as HW can provide
larger registers than 32-bit. For example, mlx5 HW would provide 4 of 32b
storage which users can use for their own sake.
	tag[0], tag[1], tag[2], tag[3]


Thanks,
Yongseok


  reply	other threads:[~2019-07-05 18:05 UTC|newest]

Thread overview: 98+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-03 21:32 [dpdk-dev] [RFC 1/3] ethdev: extend flow metadata Yongseok Koh
2019-06-03 21:32 ` [dpdk-dev] [RFC 2/3] ethdev: add flow modify mark action Yongseok Koh
2019-06-06 10:35   ` Jerin Jacob Kollanukkaran
2019-06-06 18:33     ` Yongseok Koh
2019-06-03 21:32 ` [dpdk-dev] [RFC 3/3] ethdev: add flow tag Yongseok Koh
2019-07-04 23:23   ` [dpdk-dev] [PATCH] " Yongseok Koh
2019-07-05 13:54     ` Adrien Mazarguil
2019-07-05 18:05       ` Yongseok Koh [this message]
2019-07-08 23:32         ` Yongseok Koh
2019-07-09  8:38         ` Adrien Mazarguil
2019-07-11  1:59           ` Yongseok Koh
2019-10-08 12:57             ` Yigit, Ferruh
2019-10-08 13:18               ` Slava Ovsiienko
2019-10-10 16:09     ` [dpdk-dev] [PATCH v2] " Viacheslav Ovsiienko
2019-10-24 13:12       ` [dpdk-dev] [PATCH v3] " Viacheslav Ovsiienko
2019-10-27 16:38         ` Ori Kam
2019-10-27 18:42         ` [dpdk-dev] [PATCH v4] " Viacheslav Ovsiienko
2019-10-27 19:11           ` Ori Kam
2019-10-31 18:57             ` Ferruh Yigit
2019-06-09 14:23 ` [dpdk-dev] [RFC 1/3] ethdev: extend flow metadata Andrew Rybchenko
2019-06-10  3:19   ` Wang, Haiyue
2019-06-10  7:20     ` Andrew Rybchenko
2019-06-11  0:06       ` Yongseok Koh
2019-06-19  9:05         ` Andrew Rybchenko
2019-07-04 23:21 ` [dpdk-dev] [PATCH] " Yongseok Koh
2019-07-10  9:31   ` Olivier Matz
2019-07-10  9:55     ` Bruce Richardson
2019-07-10 10:07       ` Olivier Matz
2019-07-10 12:01         ` Bruce Richardson
2019-07-10 12:26           ` Thomas Monjalon
2019-07-10 16:37             ` Yongseok Koh
2019-07-11  7:44               ` Adrien Mazarguil
2019-07-14 11:46                 ` Andrew Rybchenko
2019-07-29 15:06                   ` Adrien Mazarguil
2019-10-08 12:51                     ` Yigit, Ferruh
2019-10-08 13:17                       ` Slava Ovsiienko
2019-10-10 16:02   ` [dpdk-dev] [PATCH v2] " Viacheslav Ovsiienko
2019-10-18  9:22     ` Olivier Matz
2019-10-19 19:47       ` Slava Ovsiienko
2019-10-21 16:37         ` Olivier Matz
2019-10-24  6:49           ` Slava Ovsiienko
2019-10-24  9:22             ` Olivier Matz
2019-10-24 12:30               ` Slava Ovsiienko
2019-10-24 13:08     ` [dpdk-dev] [PATCH v3] " Viacheslav Ovsiienko
2019-10-27 16:56       ` Ori Kam
2019-10-27 18:40       ` [dpdk-dev] [PATCH v4] " Viacheslav Ovsiienko
2019-10-27 19:10         ` Ori Kam
2019-10-29 16:22         ` Andrew Rybchenko
2019-10-29 17:19           ` Slava Ovsiienko
2019-10-29 18:30             ` Thomas Monjalon
2019-10-29 18:35               ` Slava Ovsiienko
2019-10-30  6:28               ` Andrew Rybchenko
2019-10-30  7:35             ` Andrew Rybchenko
2019-10-30  8:59               ` Slava Ovsiienko
2019-10-30  9:20                 ` Andrew Rybchenko
2019-10-30 10:05                   ` Slava Ovsiienko
2019-10-30 10:03                 ` Slava Ovsiienko
2019-10-30 15:49               ` Olivier Matz
2019-10-31  9:25                 ` Andrew Rybchenko
2019-10-29 16:25         ` Olivier Matz
2019-10-29 16:33           ` Olivier Matz
2019-10-29 17:53             ` Slava Ovsiienko
2019-10-29 17:43           ` Slava Ovsiienko
2019-10-29 19:31         ` [dpdk-dev] [PATCH v5] " Viacheslav Ovsiienko
2019-10-30  8:02           ` Andrew Rybchenko
2019-10-30 14:40             ` Slava Ovsiienko
2019-10-30 14:46               ` Slava Ovsiienko
2019-10-30 15:20                 ` Olivier Matz
2019-10-30 15:57                   ` Thomas Monjalon
2019-10-30 15:58                   ` Slava Ovsiienko
2019-10-30 16:13                     ` Olivier Matz
2019-10-30  8:35           ` Ori Kam
2019-10-30 17:12           ` [dpdk-dev] [PATCH v6 0/2] extend flow metadata feature Viacheslav Ovsiienko
2019-10-30 17:12             ` [dpdk-dev] [PATCH v6 1/2] ethdev: extend flow metadata Viacheslav Ovsiienko
2019-10-31  9:19               ` Andrew Rybchenko
2019-10-31 13:05               ` [dpdk-dev] [PATCH v7 0/2] extend flow metadata feature Viacheslav Ovsiienko
2019-10-31 13:05                 ` [dpdk-dev] [PATCH v7 1/2] ethdev: extend flow metadata Viacheslav Ovsiienko
2019-10-31 15:47                   ` Olivier Matz
2019-10-31 16:13                     ` Slava Ovsiienko
2019-10-31 16:48                   ` [dpdk-dev] [PATCH v8 0/2] extend flow metadata feature Viacheslav Ovsiienko
2019-10-31 16:48                     ` [dpdk-dev] [PATCH v8 1/2] ethdev: extend flow metadata Viacheslav Ovsiienko
2019-11-04  6:13                       ` [dpdk-dev] [PATCH v9 0/2] extend flow metadata feature Viacheslav Ovsiienko
2019-11-04  6:13                         ` [dpdk-dev] [PATCH v9 1/2] ethdev: extend flow metadata Viacheslav Ovsiienko
2019-11-05 14:19                           ` [dpdk-dev] [PATCH v10 0/2] extend flow metadata feature Viacheslav Ovsiienko
2019-11-05 14:19                             ` [dpdk-dev] [PATCH v10 1/2] ethdev: extend flow metadata Viacheslav Ovsiienko
2019-11-05 14:19                             ` [dpdk-dev] [PATCH v10 2/2] ethdev: move egress metadata to dynamic field Viacheslav Ovsiienko
2019-11-06 15:49                             ` [dpdk-dev] [PATCH v10 0/2] extend flow metadata feature Ferruh Yigit
2019-11-04  6:13                         ` [dpdk-dev] [PATCH v9 2/2] ethdev: move egress metadata to dynamic field Viacheslav Ovsiienko
2019-10-31 16:48                     ` [dpdk-dev] [PATCH v8 " Viacheslav Ovsiienko
2019-10-31 17:21                       ` Olivier Matz
2019-11-01 12:34                       ` Andrew Rybchenko
2019-10-31 13:05                 ` [dpdk-dev] [PATCH v7 " Viacheslav Ovsiienko
2019-10-31 13:33                   ` Ori Kam
2019-10-31 15:51                   ` Olivier Matz
2019-10-31 16:07                     ` Slava Ovsiienko
2019-10-30 17:12             ` [dpdk-dev] [PATCH v6 " Viacheslav Ovsiienko
2019-10-31  9:01               ` Andrew Rybchenko
2019-10-31 10:54                 ` Slava Ovsiienko

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