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I need to gprof a library in our system to examine the function calls and see if we can optimize it any more. Basically, what I have is

Executable A which uses a shared Library myLib.so

I want to gprof the myLib.so. When I compile myLib.so source using -pg option, it produces a .so file just fine.

But, recompiling the Executable A against that library is not producing the *.gmon file for some reason. What needs to be done? Should I link the myLib statically? If so, please tell me how. I am a newbie, so pardon my ignorance. I am learning everyday

thanks in advance.

f4.
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ramsci
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2 Answers2

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You can do better than gprof.

You could use a good sampling profiler like RotateRight/Zoom, or you could try this technique. Also lsstack serves well. pstack does too, but is more work for you.

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Mike Dunlavey
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  • Used to be a big fan of RotateRight's Zoom profiler. Haven't needed to use it in years. Today I needed it, but the web site says development stopped in 2015. That's too bad. – Stéphane Feb 28 '20 at 22:56
  • @Stéphane: Sounds like they've got one foot on a banana peel. – Mike Dunlavey Feb 29 '20 at 01:52
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I have the same issue, but I think the best thing to do is to create a small C/C++ program that uses the library with some test calls, compile it with the library using -pg, and profile that. That way you nicely isolate the profiling issues of the library from other stuff, too.

As http://sourceware.org/binutils/docs/gprof/Implementation.html and https://stackoverflow.com/a/7290284/885650 point out, you need -pg when linking, as it adds extra code everywhere.

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j13r
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