Patchwork [iproute2] document initcwnd

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Submitter Brian Bloniarz
Date May 6, 2010, 1:37 a.m.
Message ID <4BE21D64.4040600@athenacr.com>
Download mbox | patch
Permalink /patch/51775/
State Accepted
Delegated to: stephen hemminger
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Comments

Brian Bloniarz - May 6, 2010, 1:37 a.m.
Stephen Hemminger wrote:
> On Wed, 05 May 2010 16:56:34 -0400
> Brian Bloniarz <bmb@athenacr.com> wrote:
> 
>> dormando wrote:
>>>> This sounds like TCP slow start.
>>>>
>>>> http://en.wikipedia.org/wiki/Slow-start
>>>>
>>>> As far as tunables you might want to play with the initcwnd route
>>>> flag (see "ip route help")
>>> Ah, yes, initcwnd was it. I'm well aware of TCP Congestion control / slow
>>> start / etc. However I couldn't find the damn tunable for it :)
>> Documenting the flag in ip(8) might increase its visibility
>> a little. I don't see it documented in the iproute2 git head,
>> though it shows up on http://linux.die.net/man/8/ip somehow.
>>
>> Stephen, do you know why that is?
> 
> No one sent me an official patch to change it?

Mention initcwnd in ip(8). Text taken from doc/ip-cref.tex.

Signed-off-by: Brian Bloniarz <bmb@athenacr.com>

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stephen hemminger - May 6, 2010, 2:33 a.m.
On Wed, 05 May 2010 21:37:40 -0400
Brian Bloniarz <bmb@athenacr.com> wrote:

> Stephen Hemminger wrote:
> > On Wed, 05 May 2010 16:56:34 -0400
> > Brian Bloniarz <bmb@athenacr.com> wrote:
> > 
> >> dormando wrote:
> >>>> This sounds like TCP slow start.
> >>>>
> >>>> http://en.wikipedia.org/wiki/Slow-start
> >>>>
> >>>> As far as tunables you might want to play with the initcwnd route
> >>>> flag (see "ip route help")
> >>> Ah, yes, initcwnd was it. I'm well aware of TCP Congestion control / slow
> >>> start / etc. However I couldn't find the damn tunable for it :)
> >> Documenting the flag in ip(8) might increase its visibility
> >> a little. I don't see it documented in the iproute2 git head,
> >> though it shows up on http://linux.die.net/man/8/ip somehow.
> >>
> >> Stephen, do you know why that is?
> > 
> > No one sent me an official patch to change it?
> 
> Mention initcwnd in ip(8). Text taken from doc/ip-cref.tex.
> 
> Signed-off-by: Brian Bloniarz <bmb@athenacr.com>

Ok, I will add it with an explicit caution about not doing this on public
networks.
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stephen hemminger - May 19, 2010, 3:31 p.m.
On Wed, 05 May 2010 21:37:40 -0400
Brian Bloniarz <bmb@athenacr.com> wrote:

> Stephen Hemminger wrote:
> > On Wed, 05 May 2010 16:56:34 -0400
> > Brian Bloniarz <bmb@athenacr.com> wrote:
> > 
> >> dormando wrote:
> >>>> This sounds like TCP slow start.
> >>>>
> >>>> http://en.wikipedia.org/wiki/Slow-start
> >>>>
> >>>> As far as tunables you might want to play with the initcwnd route
> >>>> flag (see "ip route help")
> >>> Ah, yes, initcwnd was it. I'm well aware of TCP Congestion control / slow
> >>> start / etc. However I couldn't find the damn tunable for it :)
> >> Documenting the flag in ip(8) might increase its visibility
> >> a little. I don't see it documented in the iproute2 git head,
> >> though it shows up on http://linux.die.net/man/8/ip somehow.
> >>
> >> Stephen, do you know why that is?
> > 
> > No one sent me an official patch to change it?
> 
> Mention initcwnd in ip(8). Text taken from doc/ip-cref.tex.

Applied
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Patch

diff --git a/man/man8/ip.8 b/man/man8/ip.8
index a5d2915..777a0a7 100644
--- a/man/man8/ip.8
+++ b/man/man8/ip.8
@@ -211,7 +211,9 @@  replace " | " monitor " } "
 .B  realms
 .IR REALM " ] [ "
 .B  rto_min
-.IR TIME " ]"
+.IR TIME " ] [ "
+.B  initcwnd
+.IR NUMBER " ]"
 
 .ti -8
 .IR TYPE " := [ "
@@ -1561,6 +1563,13 @@  the clamp for congestion window.  It is ignored if the
 flag is not used.
 
 .TP
+.BI initcwnd " NUMBER " "(2.5.70+ only)"
+Initial congestion window size for connections to this destination.
+Actual window size is this value multiplied by the MSS
+(``Maximal Segment Size'') for same connection. The default is
+zero, meaning to use the values specified in RFC2414.
+
+.TP
 .BI advmss " NUMBER " "(2.3.15+ only)"
 the MSS ('Maximal Segment Size') to advertise to these
 destinations when establishing TCP connections.  If it is not given,