Re: Terminally slow (75 seconds) on some steps

Andrew Cagney
2003-07-17T16:34:44Z

> I am trying to debug large program and I am observing unusual slowdown.
> I don't have any breakpoints, I am just running the app. I measured 75
> seconds of wall clock for single click operation that takes fraction of
> second outside debugger. Process time (as viewed by ps) of gdb increased
> by 68 seconds. I get realtime reaction with some operations and this
> delay with some other operations. When single stepping, it seems that
> the more lines must be executed the more time it takes in debugger (but
> this is in 1-5 seconds range).
>
> As if gdb was emulating every instruction. I know this isn't the case.
> However, breakpoints cause interrupts, so maybe gdb is being bogged down
> by some other interrupts, timer maybe? Given that single step can take
> one or more seconds, few timers could quickly accumulate to minute.
>
> I have also this problem that I cannot run the program twice per
> session, so I have to restart gdb and consequently reload symbols. I
> have aging snapshot from 1. April 2002.

Is this a threaded program on GNU/Linux? 5.3 contained a major
performance improvement for threaded debugging.

Also, something from April '02 is seriously old. Try either 5.3, or a
6.0 snap (see http://www.gnu.org/software/gdb/download/)