[ros-dev] Loopback problem

Phillip Susi psusi at cfl.rr.com
Wed Dec 21 21:31:36 CET 2005


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.

> You might want to cut them some slack, their code needs to be
> cross-platform. TCP/IP is available on every platform they support,
> otherwise a browser doesn't make much sense :-)
> 

Yes, but shared memory is also available on every platform ;)

> No, it is our job to make ReactOS behave like Windows, not the job of the
> app vendors to change their code to suite ReactOS.
> 

Yes, that is true, but mozilla is still poorly behaved so it would be 
nice to let them know so they can improve on it eventually.  Correctly 
implementing TCP_NODELAY should provide a decent work around to this 
poor behavior, but it would be much better if they would send the whole 
block of data at once instead of one byte at a time.


> 
> My test program does not set that flag and still works ok on Windows.
> 

It may still be slow, just not AS slow due to the lower timeout.  If 
that is the case then you should see a significant speed up by enabling 
TCP_NODELAY.  You should also see that behavior on bsd or linux systems. 
   Lowering the timeout will reduce the effects, but it will only be 
hiding the real problems.




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