Re: RFA: patch to remote.c for larger download packet support (part 1)

["Frank Ch. Eigler" <fche at cygnus dot com>]

Hi -

On Tue, Oct 05, 1999 at 02:24:31PM -0700, J.T. Conklin wrote:
> Frank> The following patches are one step in loosening the remote
> Frank> protocols' packet size limiting code, so that downloads to
> Frank> versatile targets across reliable channels may be quicker.
> Frank> This is done by making remote_write_bytes() and putpkt() be
> Frank> able to accept packets up to "remotewritesize" bytes in length.
> 
> How much faster do you expect this to be?  [...] Is it just the
> packet latency caused by a stop-and-wait protocol?  
> Assuming that the delay is in the transport layer itself, [...]

Yes, it's the latency that's a killer, for some transports, on some hosts.
My main focus is a cygwin host and a TCP-connected target.  This change,
plus a friend in generic_load(), gives 1+ order of magnitude improvement
in throughput.


> As for the patch, if a user sets remotewritesize to a value larger
> than the maximum packet size supported by the target's debug agent,
> putpkt_binary() will fail and getpkt() will time out.  

Yup.  Definitely an "expert user" option.


> But since neither error is caught, the user has no reason to believe that the
> write did not succeed.   [...]

There was no change to this part.  To whatever extent download errors have
been reported in the past, they still would be.


- FChE

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