Date: Mon, 04 Jul 2005 22:13:35 +0200 From: Christian Vogt <chvogt@tm.uka.de> To: John-Mark Gurney <gurney_j@resnet.uoregon.edu> Cc: freebsd-net@freebsd.org, TM-RO2 <tm-ro2@tm.uka.de> Subject: Re: tcp_xmit_timer() Message-ID: <42C9986F.4000601@tm.uka.de> In-Reply-To: <20050704191428.GQ727@funkthat.com> References: <42C986BB.4020409@tm.uka.de> <20050704191428.GQ727@funkthat.com>
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Yes, and this (from sys/netinet/tcp_var.h):
#define TCP_RTTVAR_SCALE 16 /* multiplier for rttvar; 2 bits */
#define TCP_RTTVAR_SHIFT 4 /* shift for rttvar; 2 bits */
...should say "...for rttvar; 4 bits frac." in both places.
- Christian
--
Christian Vogt, Institute of Telematics, University of Karlsruhe
www.tm.uka.de/~chvogt/pubkey/
John-Mark Gurney wrote:
> Christian Vogt wrote this message on Mon, Jul 04, 2005 at 20:58
> +0200:
>
>> Hi everybody,
>>
>> just a nit in sys/netinet/tcp_input.c:tcp_xmit_timer(). A comment
>> says:
>>
>> /* * srtt is stored as fixed point with 5 bits after the * binary
>> point (i.e., scaled by 8). The following magic * is equivalent to
>> the smoothing algorithm in rfc793 with * an alpha of .875 (srtt =
>> rtt/8 + srtt*7/8 in fixed * point). Adjust rtt to origin 0. */
>>
>> But it should say "...(i.e., scaled by 32)".
>>
>> Hope this wasn't mentioned before on this list.
>
>
> This isn't the only mismatch: #define TCP_RTT_SHIFT 5
> /* shift for srtt; 3 bits frac. */
>
> Maybe wollman can shed light on this? It looks like he just didn't
> update the comments in both places...
>
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