bmbm
bmbm(width = 0)
private
Sometimes benchmark results are skewed because code executed earlier encounters different garbage collection overheads than that run later. #bmbm attempts to minimize this effect by running the tests twice, the first time as a rehearsal in order to get the runtime environment stable, the second time for real. GC.start is executed before the start of each of the real timings; the cost of this is not included in the timings. In reality, though, there’s only so much that #bmbm can do, and the results are not guaranteed to be isolated from garbage collection and other effects.
Because #bmbm takes two passes through the tests, it can calculate the required label width.
require 'benchmark' array = (1..1000000).map { rand } Benchmark.bmbm do |x| x.report("sort!") { array.dup.sort! } x.report("sort") { array.dup.sort } end
Generates:
Rehearsal ----------------------------------------- sort! 11.928000 0.010000 11.938000 ( 12.756000) sort 13.048000 0.020000 13.068000 ( 13.857000) ------------------------------- total: 25.006000sec user system total real sort! 12.959000 0.010000 12.969000 ( 13.793000) sort 12.007000 0.000000 12.007000 ( 12.791000)
#bmbm yields a Benchmark::Job object and returns an array of Benchmark::Tms objects.