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

Stephen Hemminger shemminger at osdl.org
Tue Sep 26 14:08:56 PDT 2006

On Tue, 26 Sep 2006 14:39:34 -0400
"David P. Reed" <dpreed at reed.com> wrote:

> 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.

You must live in a world without power management and SMP.
The number of systems that can't get a high resolution synchronized
and stable clock seems to be increasing not decreasing!

> 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.

Stephen Hemminger <shemminger at osdl.org>

More information about the end2end-interest mailing list