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From: Johannes Berg <johannes@sipsolutions.net>
To: "Toke Høiland-Jørgensen" <toke@toke.dk>,
	make-wifi-fast@lists.bufferbloat.net,
	linux-wireless@vger.kernel.org
Subject: Re: [Make-wifi-fast] [PATCH v5] mac80211: Move reorder-sensitive TX handlers to after TXQ dequeue.
Date: Thu, 01 Sep 2016 19:59:05 +0200	[thread overview]
Message-ID: <1472752745.9608.8.camel@sipsolutions.net> (raw)
In-Reply-To: <20160901160312.31540-1-toke@toke.dk> (sfid-20160901_180539_629379_96553E29)


> To avoid having to deal with fragmentation on dequeue, the split is
> set to be after the fragmentation handler. This means that some
> reordering of TX handlers is necessary, and some handlers had to be
> made aware of fragmentation due to this reordering.

Come to think of it, that's actually counterproductive.

If a fragment is dropped, or even just if fragments are reordered, the
receiver will not be able to defragment the frame, and will thus drop
it. Therefore, it's all-or-nothing, and we shouldn't transmit any
fragment if we drop/reorder one (*).

So ... I think you'll just have to deal with fragmentation on the
codel/fq/whatever queues and keep fragments together, or do
fragmentation afterwards.

johannes


(*) also, couldn't this mean that we send something completely stupid
like

seq=1,frag=0
seq=2,frag=0
seq=2,frag=1
seq=2,frag=1

if reordering happened?

  reply	other threads:[~2016-09-01 17:59 UTC|newest]

Thread overview: 77+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-17 12:58 [Make-wifi-fast] [PATCH] mac80211: Move crypto IV generation " Toke Høiland-Jørgensen
2016-08-17 13:08 ` Johannes Berg
2016-08-17 13:16   ` Toke Høiland-Jørgensen
2016-08-17 13:18     ` Johannes Berg
2016-08-17 13:23       ` Toke Høiland-Jørgensen
2016-08-17 14:45 ` [Make-wifi-fast] [PATCH v2] " Toke Høiland-Jørgensen
2016-08-17 15:47   ` Noah Causin
2016-08-17 22:33     ` Toke Høiland-Jørgensen
2016-08-19  3:06       ` Noah Causin
2016-08-22 14:24         ` Toke Høiland-Jørgensen
2016-08-23 17:06           ` Noah Causin
2016-08-23 17:51             ` Toke Høiland-Jørgensen
2016-08-17 19:49   ` Johannes Berg
2016-08-17 20:07     ` Dave Taht
2016-08-17 20:43       ` Johannes Berg
2016-08-22 14:47         ` Toke Høiland-Jørgensen
2016-08-26  8:38           ` Johannes Berg
2016-08-26  8:54             ` Toke Høiland-Jørgensen
2016-08-24 16:20   ` [Make-wifi-fast] [PATCH v3] mac80211: Move reorder-sensitive TX handlers " Toke Høiland-Jørgensen
2016-08-24 22:40     ` Noah Causin
2016-08-25 12:45       ` Toke Høiland-Jørgensen
2016-08-26 14:30         ` Toke Høiland-Jørgensen
2016-08-26 14:51           ` Dave Taht
2016-08-30 13:15     ` [Make-wifi-fast] [PATCH v4] " Toke Høiland-Jørgensen
2016-08-30 13:17       ` Toke Høiland-Jørgensen
2016-08-31 21:06       ` Johannes Berg
2016-09-01  8:23         ` Toke Høiland-Jørgensen
2016-09-01  8:34           ` Johannes Berg
2016-09-01  8:38             ` Toke Høiland-Jørgensen
2016-09-01  9:07               ` Johannes Berg
2016-09-01  9:20                 ` Toke Høiland-Jørgensen
2016-09-01  9:27                   ` Johannes Berg
2016-09-01  9:42                     ` Toke Høiland-Jørgensen
2016-09-01 16:03       ` [Make-wifi-fast] [PATCH v5] " Toke Høiland-Jørgensen
2016-09-01 17:59         ` Johannes Berg [this message]
2016-09-01 18:30           ` Toke Høiland-Jørgensen
2016-09-01 18:35             ` Johannes Berg
2016-09-02  2:48         ` Jason Andryuk
2016-09-02  9:27           ` Toke Høiland-Jørgensen
2016-09-02 13:41         ` [Make-wifi-fast] [PATCH v6] " Toke Høiland-Jørgensen
2016-09-02 14:44           ` Toke Høiland-Jørgensen
2016-09-05 11:30           ` [Make-wifi-fast] [PATCH v7] " Toke Høiland-Jørgensen
2016-09-05 16:06             ` Toke Høiland-Jørgensen
2016-09-05 17:00               ` Dave Taht
2016-09-05 17:26                 ` Toke Høiland-Jørgensen
2016-09-05 17:59                   ` Dave Taht
2016-09-05 20:23                     ` Dave Taht
2016-09-05 20:45                       ` Toke Høiland-Jørgensen
2016-09-05 21:02                         ` Dave Taht
2016-09-05 21:25                           ` Toke Høiland-Jørgensen
2016-09-05 21:29                             ` Dave Taht
2016-09-05 21:35                               ` Toke Høiland-Jørgensen
2016-09-05 21:42                                 ` Dave Taht
2016-09-05 22:04                                   ` Dave Taht
2016-09-05 22:01                             ` Toke Høiland-Jørgensen
2016-09-05 22:08                               ` Dave Taht
2016-09-05 22:31                                 ` Dave Taht
2016-09-05 17:49             ` Felix Fietkau
2016-09-05 17:59               ` Toke Høiland-Jørgensen
2016-09-05 18:45                 ` Felix Fietkau
2016-09-06 11:43             ` Toke Høiland-Jørgensen
2016-09-06 11:45               ` Toke Høiland-Jørgensen
2016-09-06 11:44             ` [Make-wifi-fast] [PATCH v8] " Toke Høiland-Jørgensen
2016-09-06 22:04               ` Felix Fietkau
2016-09-12 12:35               ` Johannes Berg
2016-09-12 13:08                 ` Toke Høiland-Jørgensen
2016-09-12 13:19                   ` Johannes Berg
2016-09-22 17:04               ` [Make-wifi-fast] [PATCH v9 0/2] mac80211: TXQ dequeue path rework Toke Høiland-Jørgensen
2016-09-22 17:04               ` [Make-wifi-fast] [PATCH v9 1/2] mac80211: Move ieee802111_tx_dequeue() to later in tx.c Toke Høiland-Jørgensen
2016-09-30 11:13                 ` Johannes Berg
2016-09-22 17:04               ` [Make-wifi-fast] [PATCH v9 2/2] mac80211: Move reorder-sensitive TX handlers to after TXQ dequeue Toke Høiland-Jørgensen
2016-09-30 10:27                 ` Johannes Berg
2016-09-30 12:39                   ` Toke Høiland-Jørgensen
2016-09-30 12:43                     ` Johannes Berg
2016-09-30 12:45                       ` Toke Høiland-Jørgensen
2016-09-30 12:49                 ` Johannes Berg
2016-09-30 14:01                   ` Toke Høiland-Jørgensen

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