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From: Stephen Hemminger <shemminger@linux-foundation.org>
To: linux-kernel@vger.kernel.org
Subject: Re: [NOT VERY SAFE]     [TCP]: Set initial_ssthresh default to zero in Cubic and BIC.
Date: Sun, 14 Oct 2007 13:34:05 -0700	[thread overview]
Message-ID: <20071014133405.656e899a@freepuppy.rosehill> (raw)
In-Reply-To: <20071014100245.914b784a.komurojun@nifty.com>

On Sun, 14 Oct 2007 10:02:45 +0900
Komuro <komurojun@nifty.com> wrote:

> Dear David
> 
> Actually, tcp_sk(sk)->snd_ssthresh is not initialized,
> if initial_ssthresh is 0.
> 
> The patch should be
> 
>  static void bictcp_init(struct sock *sk)
>  {
>  	bictcp_reset(inet_csk_ca(sk));
> -	if (initial_ssthresh)
> -		tcp_sk(sk)->snd_ssthresh = initial_ssthresh;
> +
> +	tcp_sk(sk)->snd_ssthresh = initial_ssthresh;
>  }
>

In which case it is zero because that is the default value.

If you want to make arguments about sshtresh value, you need to provide
tcp traces of good vs problematic connection and get a good idea of
what the intermediate path and remote host OS is.  Since you are
the first to raise the issue, you will have to provide a lot of evidence
to overcome the developer suspicion that the problem is due to
buggy middle boxes, hardware or the other end.


-- 
Stephen Hemminger <shemminger@linux-foundation.org>


  parent reply	other threads:[~2007-10-14 20:34 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-06  4:26 [PATCH] Simplify yenta code Komuro
2007-10-08 17:47 ` Linas Vepstas
2007-10-13 22:36 ` [NOT VERY SAFE] [TCP]: Set initial_ssthresh default to zero in Cubic and BIC Komuro
2007-10-13 22:52   ` David Miller
2007-10-13 22:54     ` David Miller
2007-10-14  1:02   ` Komuro
2007-10-14  2:38     ` David Miller
2007-10-14  4:30       ` Jeff Garzik
2007-10-14  4:28     ` Komuro
2007-10-14  4:32       ` David Miller
2007-10-14  4:53       ` Komuro
2007-10-14  5:23         ` David Miller
2007-10-15 12:59         ` Komuro
2007-10-15 15:55           ` Stephen Hemminger
2007-10-14 20:34     ` Stephen Hemminger [this message]
2008-03-02 12:07   ` [BUG kernel 2.6.25-rc3 IPV6] ping6 -I eth0 ff02::1 causes system hang Komuro
2008-03-04  7:40     ` Andrew Morton
2008-03-08  4:44     ` Komuro
2008-03-08  5:20       ` Komuro
2008-03-08 11:56       ` David Miller

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