[commit] Run length encoding for gdbserver

[Michael Snyder]

On Thu, 2006-09-21 at 12:12 -0400, Daniel Jacobowitz wrote:
> The remote protocol supports a simple run length encoding mechanism (in only
> one direction - from the stub to the client).  This patch implements it in
> gdbserver.  It doesn't make a huge difference to overall performance, but
> can reduce the amount of data sent in some cases by 50%.

This should be a significant gain for libthread_db debugging, 
where gdb does a lot of large memory reads behind the scenes.

For stack traces it may not make that much difference, since
those reads are usually small.

Does it work for register packets too?

> 
> I realize I didn't leave any room for the equivalent operation in
> the new binary transfer packets in the direction from the client to
> the stub, e.g. for downloading.  I don't think this is a big deal.
> 
> Tested x86_64-pc-linux-gnu and checked in.
>