From: Per Hurtig <per.hurtig@kau•se>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: "Nandita Dukkipati" <nanditad@google•com>,
Netdev <netdev@vger•kernel.org>,
"Anna Brunström" <anna.brunstrom@kau•se>,
mohammad.rajiullah@kau•se, "Neal Cardwell" <ncardwell@google•com>,
"Sergei Shtylyov" <sergei.shtylyov@cogentembedded•com>
Subject: Re: [PATCH] tcp: fixing TLP's FIN recovery
Date: Mon, 09 Jun 2014 17:56:39 +0200 [thread overview]
Message-ID: <5395D937.5060801@kau.se> (raw)
In-Reply-To: <1402326259.3645.374.camel@edumazet-glaptop2.roam.corp.google.com>
On mån 9 jun 2014 17:04:19, Eric Dumazet wrote:
> On Mon, 2014-06-09 at 16:42 +0200, Per Hurtig wrote:
>> Tried to run the script, but I don't have the "common/defaults" and the
>> test scripts from the git repository fails on all TCP tests for Linux.
>> The results I listed in the enclosed packet traces are from two real
>> machines communicating with each other (with fresh net-next kernels and
>> TLP without the zero probe check), so I tend to rely more on those
>> results.
>
> Do not top post on netdev.
>
> We at Google run about 1000 packet drill tests for any functional change
> in TCP stack. This is the only way we can scale.
>
> We are not 'studying by hand' various tcpdumps when a tool can do it
> properly.
>
> Nandita asked you give a pointer to the source code explaining how fast
> retransmit was done for this specific case, but you provided a tcpdump,
> which hardly can be reproduced and be the answer to the question.
>
> So now, we are trying to have a test to reproduce the issue and check
> the fix is complete.
>
> So far, I am not really convinced. It seems the FIN _is_ retransmitted,
> but I do not see the SACK for this RTX is properly handled in time.
>
> Its one thing checking the FIN is retransmitted, its another to check
> that the SACK will trigger sensible behavior.
>
> If you carefully check your tcpdump, you'll see there is the same
> problem, and you missed it, while packetdrill exactly pointed it.
>
> Thanks
>
>
Ok, I guess you mean that the retransmission was not fast enough? But
will the same not happen if the original FIN is not lost and triggers a
SACK (i.e., if the two last data segments are still lost)?
Cheers,
Per
next prev parent reply other threads:[~2014-06-09 15:56 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-06 18:46 tcp: fixing TLP's FIN recovery Per Hurtig
2014-06-06 19:07 ` Eric Dumazet
2014-06-07 11:10 ` [PATCH] " Per Hurtig
2014-06-07 13:56 ` Sergei Shtylyov
2014-06-07 14:34 ` Per Hurtig
2014-06-08 2:58 ` Eric Dumazet
2014-06-08 7:41 ` Per Hurtig
2014-06-08 16:35 ` Eric Dumazet
2014-06-09 7:04 ` Nandita Dukkipati
2014-06-09 7:02 ` Nandita Dukkipati
2014-06-09 13:13 ` Per Hurtig
2014-06-09 14:33 ` Eric Dumazet
2014-06-09 14:39 ` Eric Dumazet
2014-06-09 14:42 ` Per Hurtig
2014-06-09 15:04 ` Eric Dumazet
2014-06-09 15:56 ` Per Hurtig [this message]
2014-06-09 16:15 ` Eric Dumazet
2014-06-09 16:24 ` Eric Dumazet
2014-06-09 18:33 ` Eric Dumazet
2014-06-12 14:21 ` Weiping Pan
2014-06-12 14:32 ` Eric Dumazet
2014-06-12 15:08 ` [PATCH v2 1/1] " Per Hurtig
2014-06-12 15:28 ` Eric Dumazet
2014-06-12 17:36 ` Nandita Dukkipati
2014-06-12 17:46 ` Neal Cardwell
2014-06-12 18:06 ` David Miller
2014-10-07 15:03 ` Josh Hunt
2014-10-07 20:17 ` David Miller
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