From: Jonathan Morton <chromatix99@gmail.com>
To: Dave Taht <dave.taht@gmail.com>
Cc: bloat-devel@lists.bufferbloat.net, Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [Bloat] Thoughts on Stochastic Fair Blue
Date: Thu, 24 Mar 2011 15:57:23 +0200 [thread overview]
Message-ID: <1EC45925-8DE2-4ABA-83AE-09A8E2290100@gmail.com> (raw)
In-Reply-To: <AANLkTikzQvp07qa9PmEP=ng8hcuNwqGDRomRoC-d7VE3@mail.gmail.com>
On 24 Mar, 2011, at 3:44 pm, Dave Taht wrote:
>> Here is the POC patch I am currently testing, with a probability to
>> "early drop" a packet of one percent per ms (HZ=1000 here), only if
>> packet stayed at least 4 ms on queue.
A fixed time threshold doesn't take into account the wildly varying bandwidths of connections. For example, 4ms will cause almost any queued packet on a 33.6K modem uplink (or a 3G or GSM tether) to be marked, yet with the 128-packet default size for SFQ, a GigE NIC will typically empty the queue before any packets reach the marking threshold.
But perhaps a heuristic such as not marking packets which are the last in their bucket would be okay, and mark everything else when the queue is more than half full.
- Jonathan
next prev parent reply other threads:[~2011-03-24 13:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <AB70D849-EC48-438E-B009-E22223CAF5E2@gmail.com>
[not found] ` <7imxklz5vu.fsf@lanthane.pps.jussieu.fr>
[not found] ` <160809C8-284C-4463-97FE-0E2F03C08589@gmail.com>
[not found] ` <1300973556.3747.9.camel@edumazet-laptop>
2011-03-24 13:44 ` Dave Taht
2011-03-24 13:55 ` Eric Dumazet
2011-03-24 13:57 ` Jonathan Morton [this message]
2011-03-24 14:20 ` Eric Dumazet
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