From: John Heffner <jheffner@psc.edu>
To: Andi Kleen <andi@firstfloor.org>
Cc: David Miller <davem@davemloft.net>,
ilpo.jarvinen@helsinki.fi, lachlan.andrew@gmail.com,
netdev@vger.kernel.org, quetchen@caltech.edu
Subject: Re: SACK scoreboard
Date: Tue, 08 Jan 2008 23:27:08 -0500 [thread overview]
Message-ID: <47844D1C.1060706@psc.edu> (raw)
In-Reply-To: <p73sl17pwfy.fsf@bingen.suse.de>
Andi Kleen wrote:
> David Miller <davem@davemloft.net> writes:
>> The big problem is that recovery from even a single packet loss in a
>> window makes us run kfree_skb() for a all the packets in a full
>> window's worth of data when recovery completes.
>
> Why exactly is it a problem to free them all at once? Are you worried
> about kernel preemption latencies?
>
> -Andi
I also wonder how much of a problem this is (for now, with window sizes
of order 10000 packets. My understanding is that the biggest problems
arise from O(N^2) time for recovery because every ack was expensive.
Have current tests shown the final ack to be a major source of problems?
-John
next prev parent reply other threads:[~2008-01-09 4:27 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <aa7d2c6d0711261023m3d2dd850o76a8f44aef022f39@mail.gmail.com>
[not found] ` <001001c83063$9adbc9d0$d5897e82@csp.uiuc.edu>
2007-11-28 23:47 ` [PATCH] tcp-illinois: incorrect beta usage Stephen Hemminger
2007-11-29 0:25 ` Lachlan Andrew
2007-11-29 0:43 ` Stephen Hemminger
2007-11-29 5:26 ` Shao Liu
2007-12-03 22:52 ` [RFC] TCP illinois max rtt aging Stephen Hemminger
2007-12-03 23:06 ` Lachlan Andrew
2007-12-03 23:59 ` Shao Liu
2007-12-04 0:32 ` Stephen Hemminger
2007-12-04 1:23 ` Lachlan Andrew
2007-12-04 8:37 ` Ilpo Järvinen
2007-12-07 3:27 ` Lachlan Andrew
2007-12-07 11:05 ` Ilpo Järvinen
2007-12-07 12:41 ` David Miller
2007-12-07 13:05 ` Ilpo Järvinen
2007-12-07 18:27 ` Ilpo Järvinen
2007-12-08 1:32 ` David Miller
2007-12-11 11:59 ` [RFC PATCH net-2.6.25 uncompilable] [TCP]: Avoid breaking GSOed skbs when SACKed one-by-one (Was: Re: [RFC] TCP illinois max rtt aging) Ilpo Järvinen
2007-12-11 12:32 ` [RFC PATCH net-2.6.25 uncompilable] [TCP]: Avoid breaking GSOed skbs when SACKed one-by-one David Miller
2007-12-12 0:14 ` Lachlan Andrew
2007-12-12 15:11 ` David Miller
2007-12-12 23:35 ` Lachlan Andrew
2007-12-12 23:38 ` David Miller
2007-12-13 0:00 ` Stephen Hemminger
2007-12-15 9:51 ` SACK scoreboard (Was: Re: [RFC PATCH net-2.6.25 uncompilable] [TCP]: Avoid breaking GSOed skbs when SACKed one-by-one) Ilpo Järvinen
2008-01-08 7:36 ` SACK scoreboard David Miller
2008-01-08 12:12 ` Ilpo Järvinen
2008-01-09 7:58 ` David Miller
2008-01-08 16:51 ` John Heffner
2008-01-08 22:44 ` David Miller
2008-01-09 1:34 ` Lachlan Andrew
2008-01-09 6:35 ` David Miller
2008-01-09 2:25 ` Andi Kleen
2008-01-09 4:27 ` John Heffner [this message]
2008-01-09 6:41 ` David Miller
2008-01-09 14:56 ` John Heffner
2008-01-09 18:14 ` SANGTAE HA
2008-01-09 18:23 ` John Heffner
2008-01-09 12:55 ` Ilpo Järvinen
2008-01-09 6:39 ` David Miller
2008-01-09 7:03 ` Andi Kleen
2008-01-09 7:16 ` David Miller
2008-01-09 9:47 ` Evgeniy Polyakov
2008-01-09 14:02 ` Andi Kleen
2007-11-29 14:12 ` [PATCH] tcp-illinois: incorrect beta usage Herbert Xu
2008-01-09 6:04 SACK scoreboard linux
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