This is the mail archive of the
mailing list for the GDB project.
Re: RFA: patch to remote.c for larger download packet support (part 1)
"J.T. Conklin" wrote:
> >>>>> "Andrew" == Andrew Cagney <firstname.lastname@example.org> writes:
> Andrew> I've the same general concern that J.T. raised. The operation
> Andrew> should be more robust and the user problably better informed.
> Perhaps we're going about this the wrong way. The target 'knows' the
> maximum packet size it can accept. So shouldn't there be a mechanism
> to negotiate the MTU between GDB and the target?
Even with such a mechanism I think that there would still need to be a
way of allowing the user to force the packet size.
A negotiation feature could be introduced as part of a later round of
> I am thinking of something like TCP MSS negotiation, where each side
> of the connection tells the other the maximum packet size it is able
> to receive.
> At present, we assume symmetric packet sizes for transmit and receive
> (remote_write_size is used to limit the size read requests as well as
> writes). I don't know whether or not it is worthwhile to support
> A possible implementation is a new query 'qMtu' (or qMss, qMru, ...),
> where the target responds with the maximum packet size it supports.
> If we decide to support asymetric packet sizes, GDB could tell the
> target with 'QMtu=XXX'. The drawback is that such negotiation would
> increase the time necessary to attach to the target. (Should these
> values include the framing overhead? What does that mean if we keep
> the existing remote protocol but change the framing scheme?)