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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Neal Cardwell <ncardwell@google.com>
Cc: David Miller <davem@davemloft.net>,
	netdev@vger.kernel.org, Eric Dumazet <edumazet@google.com>,
	Yuchung Cheng <ycheng@google.com>
Subject: Re: [PATCH net] tcp: fix RTO calculated from cached RTT
Date: Tue, 17 Sep 2013 05:21:02 -0700	[thread overview]
Message-ID: <1379420462.3457.11.camel@edumazet-glaptop> (raw)
In-Reply-To: <1379382260-29303-1-git-send-email-ncardwell@google.com>

On Mon, 2013-09-16 at 21:44 -0400, Neal Cardwell wrote:
> Commit 1b7fdd2ab5852 ("tcp: do not use cached RTT for RTT estimation")
> did not correctly account for the fact that crtt is the RTT shifted
> left 3 bits. Fix the calculation to consistently reflect this fact.
> 
> Signed-off-by: Neal Cardwell <ncardwell@google.com>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Yuchung Cheng <ycheng@google.com>
> ---
>  net/ipv4/tcp_metrics.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

Acked-by: Eric Dumazet <edumazet@google.com>

Instead of rto = 3*crtt, we had rto = 10*crtt, which was indeed
suboptimal ;)

  reply	other threads:[~2013-09-17 12:21 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-17  1:44 [PATCH net] tcp: fix RTO calculated from cached RTT Neal Cardwell
2013-09-17 12:21 ` Eric Dumazet [this message]
2013-09-17 14:32 ` Yuchung Cheng
2013-09-17 23:08   ` David Miller

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