Re: [RFA] Remote UDP support

[Andrew Cagney <ac131313 at cygnus dot com>]

> I didn't see any of these conclusions when I looked.  Oh well.  None of
> them were in the thread with the original patch or the discussion about
> queuing it for 5.1.

Must be earlier.  I'm also digging.

>> - It isn't at all reliable (rather than mostly reliable as across TCP or 
>> serial).  The entire ``T'' stop packet can be lost and neither GDB, nor 
>> the target, would notice.
> 
> 
> Certainly.  I also see a comment about the G packet needing to fit in
> one UDP packet, although I'm not 100% sure that's right.

I suspect the comment relates to a ``be nice'' to some TCP stacks, and 
possibly to the now removed packet sequence number code (never worked).

>> - it wasn't necessary - there are micro tcp implementations around that 
>> implement sufficient TCP for the remote protocol to work
> 
> 
> Still bigger than a polled UDP implementation, and much more
> complicated.  Implementing a tiny UDP stack is simple!  Sure, it isn't
> reliable at all; so use it on small networks and be careful :)

>> One theory put forward was to have GDB print a banner(6) sized warning 
>> (and get confirmation) before accepting the option.
> 
> 
> I have to admit, I don't see the point.  A big warning in the
> documentation, maybe, but such a confirmation query would drive me
> crazy if I actually needed to use this regularly.

That is the point!  I don't want to be around when someone that (shock 
horror :-) fails to read the manual and then complains that the GDB 
remote protocol isn't reliable.  What about a:

set remote 
i-do-not-understand-gdb-remote-protocol-and-foolishly-think-udp-works-so-please-enable-it 
  on

option.

Have you tried running the testsuite across UDP?

enjoy,
Andrew