#!/usr/bin/env ruby

require 'fiber'

# This program shows how the performance of Fiber.transfer degrades as the fiber
# count increases

def run(num_fibers = 100, repeats = 100000000)
	count = 0

	GC.start
	GC.disable

	fibers = []
	num_fibers.times do
		fibers << Fiber.new { loop { Fiber.yield } }
	end

	# Warmup:
	fibers.each do |f|
		f.resume
	end

	t0 = Process.clock_gettime(Process::CLOCK_MONOTONIC)

	while count < repeats
		fibers.each do |f|
			count += 1
			f.resume
		end
	end

	elapsed = Process.clock_gettime(Process::CLOCK_MONOTONIC) - t0

	puts "fibers: #{num_fibers.to_s.ljust(10)} count: #{count.to_s.ljust(10)} rate: #{(count / elapsed).round(2).to_s.ljust(10)}"
rescue Exception => e
	puts "Stopped at #{count} fibers"
	p e
end

run(*ARGV.map(&:to_i))