[GDB 7.6/GCC 4.8.0] Slowdown in GDB macro processing for cores?

Paul Smith psmith@gnu.org
Tue May 28 17:33:00 GMT 2013


On Tue, 2013-05-28 at 10:10 -0700, Doug Evans wrote:
> And I can't offhand explain why you *only* see the slowdown with a
> core file and not with a live executable.

Well, just because we haven't found a way to make it happen with live
debugging doesn't mean it couldn't :-).

Since it only seems to happen with cores generated in a specific way
(that is, not all core dumps show the issue), I assume that whatever
thing is happening in this core file is not happening with live
debugging, or at least we haven't found a way to trigger it.

> I wasn't aware of the problems with the 12/11/16 patch you found.
> I've submitted a minor improvement - IMO the real fix will involve a
> lot more effort - gdb's symbol handling is obtuse enough that it's
> easy to introduce performance regressions or even overlook basic
> performance problems.

I'll try the latest Git to see if it makes a difference.

> Is it possible to send me the binary+core+scripts+session-log?
> [Assuming it's legally possible, there are a few services I know of
> for sending large files.]

I think it should be OK: sending the core and binary, plus the macro, is
enough to show the problem.  I'll check and let you know.



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