Re: performance of multithreading gets gradually worse under gdb

Michael Snyder
2011-02-03T20:26:33Z

Markus Alber wrote:
>
> I compiled gdb-6.5 alright and it performs well as usual, without this
> problem.

Good info. What version of gdb were you using when you detected the
problem?

I ran your program stand-alone, then under gdb 7.0, then gdb 7.2CVS.
On my not-so-new system I got the following times:
stand alone: 15m33s
gdb 7.0 16m
gdb 7.2CVS 16m10s

I could not perceive any change in the cycle time from beginning to end.

GDB 7.0 did increase its memory footprint by about 3mb during the run
(3 percent). So that could indicate some leakage, around 15k per cycle.
But I can't see that as the main reason for the slow-down you're
reporting, considering that your system is not memory bound.

GDB 7.2CVS increased its memory footprint by only about 500kb during the
whole run, so you might consider giving that a try. Instructions for
getting the latest development sources are here:

http://sourceware.org/gdb/current/

If you'd be willing to contribute your little sample program, we might
be able to use it for a thread debugging stress test or something.

Michael