LNT is great tool for performance measurement. Here is introduction on LLVM Running server is http://llvm.org/perf/db_default/v4/nts/graph?show_moving_average=yes&show_moving_median=yes&moving_window_size=10&plot.0=41.1080.2&submit=Update
To have a good patch for review with extended number of context lines: $ git diff -U600 > your_readable_patch.diff But this patch will likely will fail applying to slightly different source code. Context lines should be stripped: $ combinediff -U 3 ./big.diff /dev/null > small.patch
Very good tool for duplicate code detection. https://conqat.cqse.eu/ This is the must have tool to be used if you suspect your project. Good How-to for C++ http://amr-noaman.blogspot.com/2013/04/detect-exact-and-similar-code.html