From: "Toke Høiland-Jørgensen" <toke@toke.dk>
To: Felix Fietkau <nbd@nbd.name>
Cc: make-wifi-fast@lists.bufferbloat.net,
linux-wireless@vger.kernel.org,
Michal Kazior <michal.kazior@tieto.com>,
Dave Taht <dave.taht@gmail.com>
Subject: Re: On the ath9k performance regression with FQ and crypto
Date: Wed, 17 Aug 2016 14:04:01 +0200 [thread overview]
Message-ID: <87lgzv61qm.fsf@toke.dk> (raw)
In-Reply-To: <6d471495-fa0f-f750-a4a4-f467205b94bd@nbd.name> (Felix Fietkau's message of "Wed, 17 Aug 2016 06:18:09 +0200")
Felix Fietkau <nbd@nbd.name> writes:
> I have not done any further tests, but based on your analysis, I think I
> finally understand what's causing this issue:
> The CCMP PN (crypto IV) is assigned in the tx path before a packet is
> put into the txq. It is also used to protect against replay attacks, so
> it is sensitive to reordering. The receiver is simply dropping any
> packet where the PN value is lower than the highest PN received so far.
> To fix this, we will have to move the IV/PN assignment to
> ieee80211_tx_dequeue.
Indeed this seems to be the cause of the problem. Thanks!
Will send a patch once we've run it through another couple rounds of
testing. Looks promising so far :)
-Toke
prev parent reply other threads:[~2016-08-17 12:04 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-16 20:41 On the ath9k performance regression with FQ and crypto Toke Høiland-Jørgensen
2016-08-16 20:47 ` [Make-wifi-fast] " Eric Dumazet
2016-08-16 23:16 ` Dave Täht
2016-08-17 4:18 ` Felix Fietkau
2016-08-17 12:04 ` Toke Høiland-Jørgensen [this message]
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