From: Dave Taht <dave.taht@gmail.com>
To: "Toke Høiland-Jørgensen" <toke@toke.dk>
Cc: Felix Fietkau <nbd@nbd.name>,
linux-wireless <linux-wireless@vger.kernel.org>,
Michal Kazior <michal.kazior@tieto.com>,
make-wifi-fast@lists.bufferbloat.net
Subject: Re: [Make-wifi-fast] TCP performance regression in mac80211 triggered by the fq code
Date: Tue, 12 Jul 2016 15:03:42 +0200 [thread overview]
Message-ID: <CAA93jw7eZv+rdZ-q1svG4nQsYVPNM9+hwcWE+-iFLo3p968i1Q@mail.gmail.com> (raw)
In-Reply-To: <87bn23ui87.fsf@toke.dk>
On Tue, Jul 12, 2016 at 2:57 PM, Toke Høiland-Jørgensen <toke@toke.dk> wrote:
> Dave Taht <dave.taht@gmail.com> writes:
>
>>> As for why this would happen... There could be a bug in the dequeue code
>>> somewhere, but since you get better performance from sticking everything
>>> into one queue, my best guess would be that the client is choking on the
>>> interleaved packets? I.e. expending more CPU when it can't stick
>>> subsequent packets into the same TCP flow?
>>
>> I share this concern.
>>
>> The quantum is? I am not opposed to a larger quantum (2 full size
>> packets = 3028 in this case?).
>
> The quantum is hard-coded to 300 bytes in the current implementation
> (see net/fq_impl.h).
don't do that. :)
A single full size packet is preferable, and saves going around the
main dequeue loop 5-6 times per flow on this workload.
My tests on the prior patch set were mostly at the larger quantum.
> -Toke
--
Dave Täht
Let's go make home routers and wifi faster! With better software!
http://blog.cerowrt.org
prev parent reply other threads:[~2016-07-12 13:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <11fa6d16-21e2-2169-8d18-940f6dc11dca@nbd.name>
2016-07-12 12:13 ` Dave Taht
2016-07-12 13:21 ` Felix Fietkau
2016-07-12 14:02 ` Dave Taht
2016-07-13 7:57 ` Dave Taht
2016-07-13 8:53 ` Felix Fietkau
2016-07-13 9:13 ` Dave Taht
2016-07-19 13:10 ` Michal Kazior
[not found] ` <87shvfujl4.fsf@toke.dk>
[not found] ` <CAA93jw6z53P+JCPsjYD-vaY+9vq9ZO-Ob_cXm0AE76uVcM=F9g@mail.gmail.com>
[not found] ` <87bn23ui87.fsf@toke.dk>
2016-07-12 13:03 ` Dave Taht [this message]
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