Ruby：使用join和ThreadsWait等待所有线程完成。all_等待-有什么区别？

考虑以下示例：

threads = []

(0..10).each do |_|
  threads << Thread.new do
    # do async staff there
    sleep Random.rand(10)
  end
end

使用

ThreadsWait

：

ThreadsWait.all_waits(threads)

这两种方法有什么区别吗

我知道

ThreadsWait

类还有其他有用的方法。 并特别询问

all_waits

方法。

明确说明

all_waits

将在每个线程执行后执行任何传递的块

join

不提供类似的服务

require "thwait"

threads = [Thread.new { 1 }, Thread.new { 2 }]

ThreadsWait.all_waits(threads) do |t|
  puts "#{t} complete."
end # will return nil

# output:
# #<Thread:0x00000002773268> complete.
# #<Thread:0x00000002772ea8> complete.

除此之外，

all_wait

方法最终调用

join_nowait

方法，该方法通过调用

join

来处理每个线程

如果没有任何块，我可以想象直接使用

join

会更快，因为您将减少所有

ThreadsWait

方法。所以我试了一下：

require "thwait"
require "benchmark"

loops = 100_000
Benchmark.bm do |x|
  x.report do
    loops.times do
      threads = [Thread.new { 2 * 1000 }, Thread.new { 4 * 2000 }]
      threads.each(&:join)
    end
  end

  x.report do
    loops.times do
      threads = [Thread.new { 2 * 1000 }, Thread.new { 4 * 2000 }]
      ThreadsWait.all_waits(threads)
    end
  end
end

# results:
# user       system     total       real
# 4.030000   5.750000   9.780000  ( 5.929623 )
# 12.810000  17.060000  29.870000 ( 17.807242 )

threads.each do |t|
  t.join
  puts "#{t} complete."
end # will return threads

require "thwait"
require "benchmark"

loops = 100_000
Benchmark.bm do |x|
  x.report do
    loops.times do
      threads = [Thread.new { 2 * 1000 }, Thread.new { 4 * 2000 }]
      threads.each(&:join)
    end
  end

  x.report do
    loops.times do
      threads = [Thread.new { 2 * 1000 }, Thread.new { 4 * 2000 }]
      ThreadsWait.all_waits(threads)
    end
  end
end

# results:
# user       system     total       real
# 4.030000   5.750000   9.780000  ( 5.929623 )
# 12.810000  17.060000  29.870000 ( 17.807242 )