Benchmarking a full sweep with 0 objects to free in Julia:

  julia> @benchmark GC.gc()
  BenchmarkTools.Trial: 
    memory estimate:  0 bytes
    allocs estimate:  0
    --------------
    minimum time:     64.959 ms (100.00% GC)
    median time:      66.848 ms (100.00% GC)
    mean time:        67.062 ms (100.00% GC)
    maximum time:     73.149 ms (100.00% GC)
    --------------
    samples:          75
    evals/sample:     1

Julia's not a language normally used for real time programs (and it is common to work around the GC / avoid allocating), but it is the language I'm most familiar with.

Julia's GC is generational; relatively few sweeps will be full. But seeing that 65ms -- more than 300 times slower than 200us -- makes me wonder.

Test was on an i9 7900X.