Ruby garbage collect

Question

When would you use this garbage collection method in your Ruby program(s)?

GC.start

Answer 1

When Benchmarking

I'm benchmarking some code that creates a lot of objects, and I noticed that my benchmarks vary wildly. I determined that the spikes were from garbage collection running during my benchmark.

Controlling the process manually gives me more consistent benchmarks.

def without_gc
  GC.start # start out clean
  GC.disable
  begin
    yield
  ensure
    GC.enable
  end
end

without_gc do
  Benchmark.measure { some_code }
end

That said, GC.start will cause significant slowdowns if you run it repeatedly.