Thread: Tweaking a C Function I wrote

From:
Adam Palmblad
Date:

I wanted to see if I could squeeze any more performance out of a C set
returning function I wrote.  As such, I looked to a profiler.  Is it
possible to get profile information on the function I wrote?  I've got
postmaster and my function compiled with profiling support, and can find
the gmon.out files... can I actually look at the call tree that occurs
when my function is being executed or will I be limited to viewing calls
to functions in the postmaster binary?

-Adam


From:
Neil Conway
Date:

Adam Palmblad wrote:
> can I actually look at the call tree that occurs when my function is
> being executed or will I be limited to viewing calls to functions in
> the postmaster binary?

You're the one with the gprof data, you tell us :)

It wouldn't surprise me if gprof didn't get profiling data for dlopen'ed
shared libraries (I haven't checked), but I think both oprofile and
callgrind should be able to.

(If you do decide to use gprof and you're on Linux, be sure to compile
Postgres with CFLAGS="-DLINUX_PROFILE", to get valid profiling data.)

-Neil

From:
Tom Lane
Date:

Neil Conway <> writes:
> It wouldn't surprise me if gprof didn't get profiling data for dlopen'ed
> shared libraries (I haven't checked), but I think both oprofile and
> callgrind should be able to.

None of the platforms I use are very good at this :-(.  Consider
building a special backend binary with the functions of interest
statically linked into it...

            regards, tom lane