Optimize TestSuite comparison macro compile times. #140
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Majority of the work done in this class is template-independent, so this avoid a lot of needless template instantiations.
Since this is a failure case, it doesn't really matter if it takes 10x more time at runtime. But it definitely adds more work for the compiler, and that's where most of human time is usually spent -- iterating on the test code. So don't.
Same as was done for the generic Comparator, but here it's quite a lot heavier so the impact should be bigger.
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Codecov Report
@@ Coverage Diff @@
## master #140 +/- ##
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Coverage 98.40% 98.40%
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Files 124 125 +1
Lines 9504 9541 +37
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+ Hits 9352 9389 +37
Misses 152 152
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I regularly get angry at how long large tests take to compile. Well, I guess relatively, building a heavy 6000-line
GltfImporterTest.cppin under 5 seconds is an unachievable feat in Some Other Codebases. But still.Profiling using Clang
-ftime-trace, the biggest offenders are:<sstream>include, about 160 ms / 3.5% -- depends on making Debug stream-free, which depends on ... making my own float printers<cmath>, about 40 ms / 1% -- can't really do much about this, and the more I optimize, the more this will stand outTestSuite::Compare::Container<T>::printMessage(), about 500 ms / 10% -- put it into a non-templated base. These are not so many but quite large.TestSuite::Comparator<T>::printMessage()-- put it into a non-templated base. These are tiny but quite many, so the template base might not help as much.Comparison with SpeedScope after adding a non-templated base for both
ComparatorandCompare::Containeris above -- 4.9 seconds before, 4.5 after, time spent inprintMessage()visibly shrinks. Trace files for reference:10% reduction in compile time is still not as significant as I hoped, further investigation needed:
operator<<()seems to be quite heavy, anything to optimize there?