[e2e] Are Packet Trains / Packet Bursts a Problem in TCP?

David P. Reed dpreed at reed.com
Tue Sep 26 11:39:34 PDT 2006


Fred Baker wrote:
>
> As Bob says, systems often have fairly obnoxious timing signals 
> available to them. One might hope that this could get fixed :-(
>
Not that it should matter, but I write network code every day for XP, 
OSX and Linux.  Perhaps the grandees who manage are still living in past 
decades.

The days when end-system clocks had really lousy resolution are gone, 
gone, gone.   While getting resolution below a millisecond is still not 
always possible, all of these platforms, when running on 500 MHz 
processors or better, do just fine with minimal overhead when running 
activities that need to be scheduled with millisecondish granularities.

Of course it's a little harder to do this in user space, one needs to 
know how to manage user space thread priorities.  But in the kernel, 
where networking is usually done, it's no problem.   And in user space 
it's not actually hard, you just need to RTFM.






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