Re: (remote) hellishly slow single stepping over library calls

["Kris Warkentin" <kewarken@qnx.com>]

> Not sure if this is totally related (how does pdebug differ from rsp?)
> but maybe a solution could help avr users too.
>
> Some sort of optimization here would be boon for avr users. In our
> case we use gdb to talk to our avarice program
> (http://sourceforge.net/projects/avarice) which talks to a jtagice box
> which in turn talks to the actual target device via a jtag interface.
> Single stepping is painfully slow: step, wait 1-5 seconds, step, etc.
>
> The bottleneck for us not so much sending info over the wire via rsp,
> but in reading the registers from the device via jtag. If we could
> reduce the number registers that need to be read at each step, I think
> it could speed things up.

Well, once upon a time, we would get one register at a time.  Then we
decided to optimize and get the whole regset since we can supply them to gdb
and then it won't ask for any more.  The only place this really optimizes is
when you're asking for more than one per stop which isn't the case when
single stepping.  Like I said before though, in our case it might not matter
since we have to send a packet anyway and it costs no more to have the whole
regset in there.

You, however, I could see really benefitting from this if the jtag is
relatively slow at fetching registers and you have to do it one at a time.
There isn't any way to tell the jtag to send a whole set I suppose?

cheers,

Kris