How to ensure that my pull request will not break performance?

[dzmitry-lahoda]

I have made changes for one of story. But not sure if that case, may be not so often, #59, will do degrade performance? May be some step by step guide.

[dadhi]

Good question.

• For now you can write the benchmark with BenchmarkDotNet in ..Benchmarks project.
• Ensure the benchmarked case covers affected code path.
• Create benchmark against normal Expression.Compile, and compare both compilation and delegate invocation. Save bm results.
• Change code and repeat bm, compare new and old results.

[dadhi]

Another idea from #115 discussion.

• We may CompileFast the test delegate,
• then decompile it to IL code
• then use this IL to emit and CreateDelegate to get a minimal possible time (assuming singe threaded liniar compilation)
• Compare the original and minimal compilation time so that the delta fits, e.g. 10%