From: Chris Friesen <chris.friesen@genband.com>
To: "Srećko Jurić-Kavelj" <srecko.juric-kavelj@fer.hr>
Cc: netdev@vger.kernel.org
Subject: Re: Using jiffies for tcp_time_stamp?
Date: Fri, 25 May 2012 09:58:40 -0600 [thread overview]
Message-ID: <4FBFAC30.8050508@genband.com> (raw)
In-Reply-To: <CAACrLC2CXU-DNeonWQGJTfX53ssm_asK7WQrFuWRBB77cg-YdA@mail.gmail.com>
On 05/22/2012 11:21 AM, Srećko Jurić-Kavelj wrote:
> By looking at the code it's clear that the time stamping is done with
> jiffies, and my kernel has CONFIG_HZ=100.
>
> I understand that this is for performance reasons (and the RTT
> smoothing filter is implemented with bit shifting operations), but
> would using a more precise time stamp have significant impact on
> performance? Since RTT is used to compute RTO, wouldn't there be any
> benefits of having more accurate estimate of this value?
I don't know if it would make any difference to the tcp algorithms, but
certainly on some architectures you can get a fast and accurate hardware
timestamp.
Chris
next prev parent reply other threads:[~2012-05-25 15:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAACrLC39Xdm3vTKUsjz43ZPyEq_vHxR-_Uf56SjSm+kUqxOqZg@mail.gmail.com>
2012-05-22 17:21 ` Using jiffies for tcp_time_stamp? Srećko Jurić-Kavelj
2012-05-25 15:58 ` Chris Friesen [this message]
2012-05-25 16:17 ` Dave Taht
2012-05-25 16:23 ` Srećko Jurić-Kavelj
2012-05-25 16:54 ` Eric Dumazet
2012-05-25 18:35 ` Srećko Jurić-Kavelj
2012-05-25 19:00 ` Eric Dumazet
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