I do not understand the documentation for gprof regarding how to compile your program for profiling with gprof. In g++, is it required to compile with the -g option (debugging information) in a addition to the -pg option or not. In each case I get different results, and I would like to see where the bottlenecks in my application are in release mode, not in debug mode, where many optimizations are left out by the compiler (e.g. inlining)
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myahya
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http://stackoverflow.com/questions/1777556/alternatives-to-gprof/1779343#1779343 – Mike Dunlavey May 04 '10 at 11:31
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1`-g` does not mean that optimizations are turned off. `-O` controls opimization. You can compile with both `-g` and `-O2` for example. – Paul Coccoli Oct 08 '14 at 00:59
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The documentation shows that you can do either, noting that you need -g for line by line profiling. So if you want to profile under release conditions, and can accept not doing line-by-line, you should be able to compile without -g.
Matthew Flaschen
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I am only interested in function calls, not line by line profiling. Without the -g option, many functions that are being called do not show up. I do not think this is due to inlining, because many of those methods are big ones (50+ lines of code). – myahya May 03 '10 at 20:16
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1@myahya, I think it very well may be inlining. By default, GCC may inline functions up to 400 internal GCC instructions long (I know these don't map directly to lines of code); see http://bazaar.launchpad.net/~vcs-imports/gcc/trunk/annotate/99780/gcc/params.def#L58. Also, what compilation flags are you using? – Matthew Flaschen May 03 '10 at 21:58