netdev - Re: [PATCH] sch_sfq: revert dont put new flow at the end of flows

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Message-ID: <1331701332.2456.25.camel@edumazet-laptop>
Date:	Tue, 13 Mar 2012 22:02:12 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Dave Taht <dave.taht@...il.com>
Cc:	jdb@...x.dk, David Miller <davem@...emloft.net>,
	netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH] sch_sfq: revert dont put new flow at the end of flows

Le mercredi 14 mars 2012 à 04:52 +0000, Dave Taht a écrit :

> I had some hope for a semi-random alternating queue
> 

I spent some time implementing two queues, one for new flows, one for
old flows. As soon as a new flow uses its initial quantum, its moved at
the tail of 'old flows queue'.

But I always could find a way to starve some flows, even adding some
kind of persistence. Right now, as soon as we empty one flow, we forget
its history.

Next packet coming will create a "new flow" with a full quantum credit,
even if we nearly consume all flow quantum in the last micro second.

Thats definitely not a trivial problem.

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