Add gprof profiling support. #7547
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I have updated the title description according to the recent changes. |
Rossmaxx
changed the title
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I was wondering if it makes sense to allow gprof even in Debug mode. At least, it turned out that the results were not so far from the Release mode results. Still, I wonder if we should print a warning if gprof is active in Debug mode, so the user knows that the results may not be representative? |
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I'll merge this in 2 days if no one objects. I choose to merge this with 1 approval because this is a trivial PR and shouldn't have any impact other than the flag |
Still, I wonder if we should print a warning if gprof is active in Debug mode, so the user knows that the results may not be representative? saw this now after I took another look. I could but I choose not to for now. I don't see any need to add a warning, building on debug mode, one should naturally know that the performance won't be good. |
| @@ -664,6 +665,20 @@ elseif(MSVC) | |||
| add_compile_options("/utf-8") | |||
| ENDIF() | |||
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| # gcc builds support gprof for profiling | |||
| if(NOT CMAKE_CXX_COMPILER_ID MATCHES "GNU") | |||
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It's supported by Clang too: https://clang.llvm.org/docs/ClangCommandLineReference.html#cmdoption-clang-pg.
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should modifying the matches string to "GNU|CLANG" suffice or is there any other syntax which I should be looking at?
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I have made the change for now, if it's wrong, just follow up on it and i'll change it.
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@sakertooth can you test for me using clang if this syntax works and you can use gprof?
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I tried to use it, but seems like the functionality is different under clang, or I'm not understanding something.
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I asked gpt (don't judge me for this), here's what it said.
Recent versions of Clang may not fully support gprof. The -pg flag might be accepted but not functional, as gprof is increasingly considered outdated. Instead, Clang recommends using more modern profiling tools like perf, llvm-profdata, or llvm-cov.
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I am thinking of not adding clang support for now. If anyone needs it, we can add it later anyway. I hope everyone agrees with this.
This reverts commit 0256dcf.
Adds gprof support for profiling the builds. Also removed the
-fomit-frame-pointerflag from swh and tap suite as the flag interferes with the-pgflag used here.per https://stackoverflow.com/questions/14666665/trying-to-understand-gcc-option-fomit-frame-pointer , this option makes getting stack traces nearly impossible, and the performance improvements seems to be negligible on 64 bit systems, especially when debugging.
to use gprof:
after building with the
WANT_DEBUG_GPROFflag turned on, run lmms, and after running,gprof ./lmms gmon.out > report.txtfrom the build directory. This will generate a text file with the profiling data. Do note that this method is tested only on GCC, and windows builds might not be supported.