From: Neal Cardwell <ncardwell@google.com>
To: Teodor Milkov <tm@del.bg>
Cc: Netdev <netdev@vger.kernel.org>, Yuchung Cheng <ycheng@google.com>
Subject: Re: [PATCH net] tcp: restrict F-RTO to work-around broken middle-boxes
Date: Mon, 19 Feb 2018 13:05:41 -0500 [thread overview]
Message-ID: <CADVnQymMwZ3=GMB4wfzAJpE2tth__UnHunAhaDFPUsO9MeTpgA@mail.gmail.com> (raw)
In-Reply-To: <33316bd2-da03-0dbb-bd41-4ff44eb81402@del.bg>
On Mon, Feb 19, 2018 at 11:17 AM, Teodor Milkov <tm@del.bg> wrote:
> On 19.02.2018 15:38, Neal Cardwell wrote:
>>
>> On Sun, Feb 18, 2018 at 4:02 PM, Teodor Milkov <tm@del.bg> wrote:
>>>
>>> Hello,
>>>
>>> I've numerous reports from Windows users that after kernel upgrade from
>>> 4.9
>>> to 4.14 they experienced major slow downs and transfer stalls.
>>>
>>> After some digging, I found that the slowness starts with this commit:
>>>
>>> tcp: extend F-RTO to catch more spurious timeouts (89fe18e44)
>>>
>>>
>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=89fe18e44f7ee5ab1c90d0dff5835acee7751427
>>>
>>> Which is partially reverted later with this one:
>>>
>>> tcp: restrict F-RTO to work-around broken middle-boxes (cc663f4d4)
>>>
>>>
>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cc663f4d4c97b7297fb45135ab23cfd508b35a77
>>>
>>> But, still, we had stalls until I fully reverted 89fe18e44.
>>
>> Thanks for the report. Do you have any other details that might help
>> evaluate this issue?
>
>
> I'm sorry I didn't provide more info. It was long session.
>
>> Any packet traces, by any chance?
>
>
> I'll try and obtain one.
Great! Yes, if you could obtain a sender-side tcpdump that captured
one of these slow-down/stalls, that would be fantastic. It would be
great to be able to understand what's going on.
We only need headers, so something like the following would be fine:
tcpdump -c2000000 -w /tmp/test.pcap -s 120 -i $ETH_DEVICE port $PORT
Then if you could post on a web server or Google drive, etc, that'd be great.
Thanks for all the additional details!
neal
next prev parent reply other threads:[~2018-02-19 18:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-07 18:42 [PATCH net] tcp: restrict F-RTO to work-around broken middle-boxes Yuchung Cheng
2017-04-07 18:45 ` David Miller
2018-02-18 21:02 ` Teodor Milkov
2018-02-19 13:38 ` Neal Cardwell
2018-02-19 16:17 ` Teodor Milkov
2018-02-19 18:05 ` Neal Cardwell [this message]
2018-02-21 12:38 ` Teodor Milkov
2018-02-21 16:57 ` Neal Cardwell
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