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From: "Ward, David - 0663 - MITLL" <david.ward@ll.mit.edu>
To: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	Bruce Osler <brosler@cisco.com>, Cyril Chemparathy <cyril@ti.com>
Subject: Re: [PATCH 4/4] net_sched: gred: actually perform idling in WRED mode
Date: Thu, 13 Sep 2012 15:38:26 -0400	[thread overview]
Message-ID: <50523632.60703@ll.mit.edu> (raw)
In-Reply-To: <50522106.40404@mojatatu.com>

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On 13/09/12 14:08, Jamal Hadi Salim wrote:
> On 12-09-13 11:22 AM, David Ward wrote:
>> gred_dequeue() and gred_drop() do not seem to get called when the
>> queue is empty, meaning that we never start idling while in WRED
>> mode. And since qidlestart is not stored by gred_store_wred_set(),
>> we would never stop idling while in WRED mode if we ever started.
>> This messes up the average queue size calculation that influences
>> packet marking/dropping behavior.
>>
>> Now, we start WRED mode idling as we are removing the last packet
>> from the queue. Also we now actually stop WRED mode idling when we
>> are enqueuing a packet.
>>
>> Cc: Bruce Osler <brosler@cisco.com>
>> Signed-off-by: David Ward <david.ward@ll.mit.edu>
> This is one is not so obvious. Iam assuming you vetted it via some tests.
> In which case:
> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
>
> cheers,
> jamal
>

Before applying this patch, the average queue size (as seen with "tc -s 
qdisc") remained constant forever after I stopped sending any packets 
through the interface -- it didn't taper off as you would expect.  After 
the patch, the average queue size will now taper off if packets are not 
being sent.

David


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  reply	other threads:[~2012-09-13 19:38 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-13 15:22 [PATCH 1/4] net_sched: gred: correct comment about qavg calculation in RIO mode David Ward
2012-09-13 15:22 ` [PATCH 2/4] net_sched: gred: eliminate redundant DP prio comparisons David Ward
2012-09-13 18:00   ` Jamal Hadi Salim
2012-09-13 20:10     ` David Miller
2012-09-13 15:22 ` [PATCH 3/4] net_sched: gred: fix qave reporting via netlink David Ward
2012-09-13 18:01   ` Jamal Hadi Salim
2012-09-13 20:10     ` David Miller
2012-09-13 15:22 ` [PATCH 4/4] net_sched: gred: actually perform idling in WRED mode David Ward
2012-09-13 18:08   ` Jamal Hadi Salim
2012-09-13 19:38     ` Ward, David - 0663 - MITLL [this message]
2012-09-13 20:10       ` David Miller
2012-09-13 20:37       ` Jamal Hadi Salim
2012-09-13 17:59 ` [PATCH 1/4] net_sched: gred: correct comment about qavg calculation in RIO mode Jamal Hadi Salim
2012-09-13 20:10   ` David Miller

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