From: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
To: Andi Kleen <ak@suse.de>
Cc: "Vladimir B. Savkin" <master@sectorb.msk.ru>,
Jesper Dangaard Brouer <hawk@diku.dk>,
Harry Edmon <harry@atmos.washington.edu>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: Network performance degradation from 2.6.11.12 to 2.6.16.20
Date: Mon, 18 Sep 2006 20:28:47 +0400 [thread overview]
Message-ID: <20060918162847.GA4863@ms2.inr.ac.ru> (raw)
In-Reply-To: <200609181754.37623.ak@suse.de>
Hello!
> Hmm, not sure how that could happen. Also is it a real problem
> even if it could?
As I said, the problem is _occasionally_ theoretical.
This would happen f.e. if packet socket handler was installed
after IP handler. Then tcpdump would get packet after it is processed
(acked/replied/forwarded). This would be disasterous, the results
are unparsable.
I recall, the issue was discussed, and that time it looked more
reasonable to solve problems of this kind taking timestamp once
before it is seen by all the rest of stack. Who could expect that
PIT nightmare is going to return? :-)
> Then it has to use the ACPI pmtmr which is really really slow.
> The overhead of that thing is so large that you can clearly see it in
> the network benchmark.
I see. Thank you.
Alexey
next prev parent reply other threads:[~2006-09-18 16:29 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-06-16 16:01 Harry Edmon
2006-06-17 22:35 ` Andrew Morton
2006-06-17 23:23 ` Harry Edmon
2006-06-17 23:56 ` Andrew Morton
2006-06-18 3:16 ` Stephen Hemminger
2006-06-18 23:23 ` Harry Edmon
2006-06-19 13:54 ` Harry Edmon
2006-06-20 2:11 ` Herbert Xu
2006-06-19 14:47 ` Jesper Dangaard Brouer
2006-06-19 15:24 ` Andi Kleen
2006-06-19 17:34 ` Chris Friesen
2006-06-19 20:39 ` Andi Kleen
2006-06-19 18:24 ` Jesper Dangaard Brouer
2006-06-25 21:51 ` Harry Edmon
2006-06-26 4:20 ` Bill Fink
2006-06-25 22:22 ` Willy Tarreau
2006-06-26 5:23 ` Andi Kleen
2006-07-04 11:41 ` Jesper Dangaard Brouer
2006-07-04 11:54 ` Andi Kleen
2006-07-10 10:55 ` Jesper Dangaard Brouer
2006-09-16 12:08 ` Vladimir B. Savkin
2006-09-18 8:35 ` Andi Kleen
2006-09-18 9:03 ` Vladimir B. Savkin
2006-09-18 9:58 ` Andi Kleen
2006-09-18 10:29 ` Vladimir B. Savkin
2006-09-18 11:27 ` Andi Kleen
2006-09-18 15:38 ` Alexey Kuznetsov
2006-09-18 15:54 ` Andi Kleen
2006-09-18 16:28 ` Alexey Kuznetsov [this message]
2006-09-18 16:50 ` Andi Kleen
2006-09-18 21:03 ` Alexey Kuznetsov
2006-09-18 21:22 ` David Miller
2006-09-18 21:46 ` Alexey Kuznetsov
2006-09-19 5:55 ` Andi Kleen
2006-09-19 20:31 ` Thomas Graf
2006-09-19 20:43 ` Andi Kleen
2006-09-19 5:52 ` Andi Kleen
2006-09-18 21:18 ` Vladimir B. Savkin
2006-09-18 22:00 ` Alexey Kuznetsov
2006-09-18 21:57 ` David Lang
2006-09-19 19:40 ` David Miller
2006-09-19 19:44 ` Stephen Hemminger
2006-09-18 22:03 ` Vladimir B. Savkin
2006-09-19 19:41 ` David Miller
2006-09-19 19:47 ` David Miller
2006-09-22 15:35 ` Alexey Kuznetsov
2006-09-22 15:43 ` Andi Kleen
2006-09-22 16:51 ` Rick Jones
2007-03-06 13:25 ` Packet timestamps (was: Re: Network performance degradation from 2.6.11.12 to 2.6.16.20) Vladimir B. Savkin
2007-03-06 14:38 ` Eric Dumazet
2007-03-06 14:43 ` Vladimir B. Savkin
2007-03-06 15:16 ` Eric Dumazet
2007-03-06 18:15 ` Vladimir B. Savkin
2006-09-18 21:08 ` Network performance degradation from 2.6.11.12 to 2.6.16.20 Vladimir B. Savkin
2006-09-18 14:09 ` David Miller
2006-09-18 14:29 ` Andi Kleen
2006-09-18 15:19 ` Alan Cox
2006-09-18 15:19 ` Andi Kleen
2006-06-19 16:40 ` Harry Edmon
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