From: Dave Taht <dave.taht@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: codel@lists.bufferbloat.net, bloat <bloat@lists.bufferbloat.net>,
"Dave Täht" <dave.taht@bufferbloat.net>
Subject: Re: [Codel] [PATCH v12] codel: Controlled Delay AQM
Date: Wed, 9 May 2012 09:08:06 -0700 [thread overview]
Message-ID: <CAA93jw5gu2nFwiQ9vmA5_=hnfkoF5B+kJfh+Fpc2m-dp-y5AGQ@mail.gmail.com> (raw)
In-Reply-To: <1336578874.12504.40.camel@edumazet-glaptop>
On Wed, May 9, 2012 at 8:54 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> On Wed, 2012-05-09 at 08:47 -0700, Dave Taht wrote:
>> Doing (or leveraging) the timestamp on actual ingress to the system,
>> rather than entrance to the exiting queue, more accurately will
>> compensate for overall system loading and the overhead of traversing
>> 3+ pages of function calls to get it from the
>> entrance point to the exit, and should result in 'tighter' results.
>
>
> Most qdiscs dont need this timestamp, so it would add overhead in fast
> path.
>
> Also, the delta between 'entering' qdisc layer and entering codel
> enqueue is almost a constant for a given qdisc/filter setup, and less
> than one us :
>
> If you really want to take it into account, replace 'target 5000us' by
> 'target 5001 us'
In the special case of routers and switches with codel on by default,
I think it would help. I can code it up....
>
>
--
Dave Täht
SKYPE: davetaht
US Tel: 1-239-829-5608
http://www.bufferbloat.net
next prev parent reply other threads:[~2012-05-09 16:08 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-07 5:35 [Codel] [PATCH v9] " Dave Täht
2012-05-07 5:50 ` Eric Dumazet
2012-05-07 5:52 ` Dave Taht
2012-05-07 5:51 ` Dave Taht
2012-05-07 13:57 ` [Codel] [PATCH v10] " Eric Dumazet
2012-05-07 16:07 ` [Codel] [PATCH v1 ] sfq: add a Controlled Delay option Eric Dumazet
2012-05-09 13:50 ` [Codel] [PATCH v12] codel: Controlled Delay AQM Eric Dumazet
2012-05-09 13:54 ` [Codel] [PATCH v12 iproute2] " Eric Dumazet
2012-05-09 15:47 ` [Codel] [PATCH v12] " Dave Taht
2012-05-09 15:54 ` Eric Dumazet
2012-05-09 16:08 ` Dave Taht [this message]
2012-05-09 16:14 ` Eric Dumazet
2012-05-09 16:32 ` [Codel] [Bloat] " Josh Hunt
2012-05-09 16:37 ` Eric Dumazet
2012-05-10 17:51 ` [Codel] [PATCH v13 net-next] " Eric Dumazet
2012-05-11 3:36 ` David Miller
2012-05-11 6:01 ` Eric Dumazet
2012-05-14 17:35 ` Simon Barber
2012-05-14 20:08 ` [Codel] [Bloat] " Dave Hart
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