Re: [PATCH 0/2] Better handling of slow remote transfers

[Pedro Alves <palves@redhat.com>]

On 08/12/2015 02:02 PM, Gary Benson wrote:
>>>> > > > I was only OK with trying to make transfers interruptible in the
>>>> > > > branch assuming it was something non-invasive, like a missing
>>>> > > > QUIT here and there.
>>> > > 
>>> > > No, gdbserver sends the data in PBUFSIZ chunks, but GDB reads the
>>> > > data a character at a time.
>> > 
>> > Can you expand on this?  What code is it that reads the data a
>> > character at a time?  What data is gdb getting at when it does that?
> I was looking in getpkt_or_notif_sane_1, but I think maybe I misread
> it.  I'll get back to you on this...

That's the very low level of RSP packets, which as you noted will
have a reasonable cap.  It sounds to me there's a loop somewhere in
a higher layer that is missing a QUIT.  E.g., we have quits
in dwarf2read.c which allow interrupting reading big binaries,
even if locally.  So what is the higher level operation that
gdb is doing when you try to interrupt, but can't?

Thanks,
Pedro Alves