[Tinyos-devel] Multihop constants

polastre at EECS.Berkeley.EDU polastre at EECS.Berkeley.EDU
Tue Jun 29 15:19:17 PDT 2004

Changing the table size requires quite a bit of familiarity with the code; whereas changing the queue length does not (I think most of us know what happens if we change the queue size).

We have about 9.5 million different #ifndef statements for defining things.  If you're proposing adding more of these in a header file, that's fine.  But at some point we have stop hacking these constants into a header file and find a better way to build applications (which is really what the Comm + UART discussion was getting at) than using -Dblah -Dblah2 -Dblah97...


----- Original Message -----
From: Philip Levis <pal at eecs.berkeley.edu>
Date: Tuesday, June 29, 2004 3:14 pm
Subject: Re: [Tinyos-devel] Multihop constants

> On Tuesday, June 29, 2004, at 02:54 PM, polastre at eecs.berkeley.edu 
> wrote:
> > Some of them are modifyable through an interface (like the time 
> > between route update messages).  It may just be an issue that 
> more of 
> > them should be modifiable through that interface.
> >
> Sure, you can change some of them at runtime... but I'm wondering 
> why 
> the default constants can't be modified, if there's any reason for 
> their being enums. Runtime configuration is useful, of course, but 
> it's 
> nice to also be able to configure things at compile time. 
> Additionally, 
> run-time requires state (RAM). It seems kind of wasteful, for 
> example, 
> to store  a tree root address in RAM.
> > Things like table size are kind of odd to specify.
> Not when the default is 16 entries! I thought you wanted to cut 
> down 
> RAM consumption. The defaults for multihop lead to about 1.3K of 
> RAM 
> usage, just for routing. You can configure the QueuedSend queue 
> length 
> and multihop forwarding queue length at the command line, but not 
> the 
> neighbor table size or tree root.
> Phil
> -------
> "We shall not cease from exploration
> And the end of all our exploring
> Will be to arrive where we started
> And know the place for the first time."
> - T. S. Eliot,  'Little Gidding'

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