Perf: Improve performance of multithreaded --check
and undefined-field
diagnostic
#2738
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Recently I am integrating LuaLs into our project's CI and I am looking for ways to speed up the process. The following are 2 simple optimizations that I have found:
Work distribution in multi-threaded
--check
I found this recently added multi-threaded
--check
in #2638. Upon some code reviewing I suspect that the hash function used to distribute work across multi threads is not that perfect, which limits its full potential. I simply changed it to Round Robin (after sorting the file list of course), and this yields another10%
performance gain in my project workspace (500+ lua files). Benchmarks as follow:I would like to mention @emmericp here as this function is originally implemented by him, to see if this small optimization can help shaving off a few more seconds in his project 😄 (great work btw 👍 )
Early break in
undefined-field
diagnosticUpon some profiling, the
undefined-field
check is quite time consuming. By looking into the code I found the early break logic of it can be optimized. The#vm.getDefs(src) > 0
is used to check if there is any definition for a givensrc
object, and there is no need to fetch the full definitions list. We can actually return as soon as the 1st definition is found. This yields a25%
performance gain in this single check within my workspace 🚀"diagnostics.severity": { "undefined-field": "Error!" }
in.luarc.json
then run with--checklevel=Error
NOTE: The following is run in single thread to avoid confusion with the above threaded optimization.