Re: [PATCH] Make remote transfers interruptible

[Sandra Loosemore <sandra at codesourcery dot com>]

On 08/12/2015 08:30 AM, Gary Benson wrote:
> Hi Sandra,
>
> Sandra Loosemore wrote:
> > On 08/05/2015 09:28 AM, Gary Benson wrote:
> > > This commit makes it possible to interrupt slow remote file transfers.
> > >
> > > gdb/ChangeLog:
> > >
> > > 	* gdb_bfd.c (gdb_bfd_iovec_fileio_pread): Add QUIT call.
> >
> > It still does not work for me.  :-(
>
> Could you please try this newer version and see if it allows you to
> interrupt the remote transfers?

This version still doesn't make the transfer interruptable with ^C. 
*But*, with this patch, the startup time is reduced from 4 minutes to 19 
seconds.  Huh?  Is it really transferring the entire file contents, or 
was the time being used for some GDB-side operation that is quadratic or 
exponential in the size of the read requested rather than the actual 
byte transfer?  Independently of the ^C issue, I think we need to better 
understand what is going on here and better tune the code on both sides 
of the RSP for large file transfers.  Even if a user asks for 
target-side libraries explicitly, 4 minutes to transfer one library 
doesn't provide a good user experience, and 19 seconds isn't so great 
either when you consider that some interactive applications link with 
dozens of GUI or multimedia libraries and not just glibc.

-Sandra