valgrind-macos VS gperftools

> There's a nice synergy between using Mac and Linux - many of the same scripts, commands, and concepts work identically.

I switched to a Mac a few months ago from Windows and I kinda hate the small differences with Linux, I like WSL much better. On top of my head,

- No systemd

- No native docker

- No valgrind (there is https://github.com/LouisBrunner/valgrind-macos though)

I basically have to install a Linux VM on Mac just for this, at which point WSL on Windows is a much better tradeoff IMO.

As far as I know there are only two of us contributing to it - Louis Brunner and myself, both very much part time volunteers.

There is ongoing work here https://github.com/LouisBrunner/valgrind-macos (and I have a repo that is based on the same changes, and a bit more up do date upstream here https://github.com/paulfloyd/macos_valgrind). Anyone that can help with this is most welcome!

BTW, it seems like there is some work ongoing for working Valgrind in later macOS versions: https://github.com/LouisBrunner/valgrind-macos/issues/19

For profiling you are right clang has no -pg that works. But there are options, since clang supports PGO the fprofile flags could be what you need. they will generated a profraw file for you. There is also gperf tools which work for more than just linux. https://github.com/gperftools/gperftools

Because we couldn't identify the issue using the results we got from Callgrind, we reached for another profiler, gperftools. It's a sampling profiler and therefor it has a smaller impact on the application's performance in exchange for less accurate call statistics. After filtering out the unimportant parts and visualizing the rest with pprof, it was evident that something strange was happening with the send function. It took only 71 milliseconds with the previous implementation and more than 900 milliseconds with the new implementation of our Bolt server. It was very suspicious, but based on Callgrind, its cost was almost the same as before. We were confused as the two results seemed to conflict with each other.

gprftools (https://github.com/gperftools/gperftools) can be easily plugged in using LD_PRELOAD and signal, and has nice go implemented visualization tool https://github.com/google/pprof.

Google's tcmalloc