From: Yuri Chislov <yuri@itinteg•net>
To: David Miller <davem@davemloft•net>
Cc: akpm@linux-foundation•org, netdev@vger•kernel.org,
bugzilla-daemon@bugzilla•kernel.org,
bugme-daemon@bugzilla•kernel.org
Subject: Re: [Bugme-new] [Bug 18952] New: The mount of SYN retries is not equal to /proc/sys/net/ipv4/tcp_syn_retries
Date: Mon, 27 Sep 2010 10:07:06 +0200 [thread overview]
Message-ID: <201009271007.06705.yuri@itinteg.net> (raw)
In-Reply-To: <20100924.200557.229751150.davem@davemloft.net>
It looks like the behavior changed in 2.6.32. 2.6.32 and up, uses some
calculation instead of a direct definition of the retries number, that makes it
harder to achieve the necessary system behavior.
The default behavior of the system changed completely
(the old default connect timeout was ~ 180 seconds, while the new one is ~21
sec).
The new behavior invalidates the kernel documentation and tcp man page.
It's not possible to set a connect timeout > 25 sec in the applications while
using the default values in /proc.
>From my view point is regression.
On Saturday, September 25, 2010 05:05:57 am David Miller wrote:
> tcp_syn_retries is not an exact calculation.
>
> It is input into a calculation which estimates how long that many
> retransmits (with suitable backoff applied) will take, and that time
> estimte in turn determines the time limit for when we'll kill the
> connection attempt.
>
> Feel free to update the documentation in
> Documentation/networking/ip-sysctl.txt to more closely match the
> behavior.
>
> The logic is in net/ipv4/tcp_timer.c:retransmits_timed_out().
next prev parent reply other threads:[~2010-09-27 8:13 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-18952-10286@https.bugzilla.kernel.org/>
2010-09-22 9:02 ` [Bugme-new] [Bug 18952] New: The mount of SYN retries is not equal to /proc/sys/net/ipv4/tcp_syn_retries Andrew Morton
2010-09-25 3:05 ` David Miller
2010-09-27 8:07 ` Yuri Chislov [this message]
2010-09-27 8:10 ` David Miller
2010-09-27 8:35 ` Damian Lukowski
2010-09-27 20:00 ` Damian Lukowski
2010-09-28 4:52 ` David Miller
2010-09-28 7:40 ` Yuri Chislov
2010-09-28 9:47 ` Ilpo Järvinen
2010-09-28 12:08 ` Yuri Chislov
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