[ros-dev] Loopback problem

Joseph Galbraith galb at vandyke.com
Wed Dec 21 22:27:11 CET 2005


Phillip Susi wrote:
> Ge van Geldorp wrote:
>> I'm not arguing that delayed ACK is incorrect, but 2.5 sec???
>> Searching the
>> Internet, 200ms seems a much more accepted value. This is also the value
>> used by the MS stack:
>> http://www.microsoft.com/technet/itsolutions/network/deploy/depovg/tcpip2k.m
>>
>> spx (under "Delayed Acknowledgements").
> 
> That does sound like a more reasonable value, but if nagling is
> disabled, it should not matter.

If an app is going to send one byte at a time, disabling
the nagle algorithm is _exactly_ the _wrong_ thing to do!

The nagle algorithm exists precisely so that applications can
send one byte at a time and not have sucky performance.

Now if an app is _always_ going to do

  send();
  recv();

(i.e., there is going to be one call to send followed by a call
to recv, disabling nagle might be appropriate.)

But any app that does:

  send();
  send();
  .
  .
  .
  send();
  recv();

Should not disable the nagel algorithm except in rare (I can't
think of any) circumstances.

Thanks,

Joseph



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