ruby中并发并行与全局锁详解

require 'benchmark'

def f1
 puts "sleep 3 seconds in f1n"
 sleep 3
end

def f2
 puts "sleep 2 seconds in f2n"
 sleep 2 
end

Benchmark.bm do |b|
 b.report do
 f1
 f2
 end 
end
## 
## user  system  total  real
## sleep 3 seconds in f1
## sleep 2 seconds in f2
## 0.000000 0.000000 0.000000 ( 5.009620)

# 接上述代码
Benchmark.bm do |b|
 b.report do
 threads = []
 threads << Thread.new { f1 }
 threads << Thread.new { f2 }
 threads.each(&:join)
 end 
end
##
## user  system  total  real
## sleep 3 seconds in f1
## sleep 2 seconds in f2
## 0.000000 0.000000 0.000000 ( 3.005115)

def thread_test
 time = Time.now
 threads = 3.times.map do 
  Thread.new do
  sleep 3 
  end
 end
 puts "不用等3秒就可以看到我:#{Time.now - time}"
 threads.map(&:join)
 puts "现在需要等3秒才可以看到我:#{Time.now - time}"
end
test
## 不用等3秒就可以看到我:8.6e-05
## 现在需要等3秒才可以看到我:3.003699

require 'benchmark'
def multiple_threads
 count = 0
 threads = 4.times.map do 
 Thread.new do
  2500000.times { count += 1}
 end
 end
 threads.map(&:join)
end

def single_threads
 time = Time.now
 count = 0
 Thread.new do
 10000000.times { count += 1}
 end.join
end

Benchmark.bm do |b|
 b.report { multiple_threads }
 b.report { single_threads }
end
##  user  system  total  real
## 0.600000 0.010000 0.610000 ( 0.607230)
## 0.610000 0.000000 0.610000 ( 0.623237)

require 'benchmark'
require 'net/http'

# 模拟网络请求
def multiple_threads
 uri = URI("http://www.baidu.com")
 threads = 4.times.map do 
 Thread.new do
  25.times { Net::HTTP.get(uri) }
 end
 end
 threads.map(&:join)
end

def single_threads
 uri = URI("http://www.baidu.com")
 Thread.new do
 100.times { Net::HTTP.get(uri) }
 end.join
end

Benchmark.bm do |b|
 b.report { multiple_threads }
 b.report { single_threads }
end

 user  system  total  real
0.240000 0.110000 0.350000 ( 3.659640)
0.270000 0.120000 0.390000 ( 14.167703)

@a = 1
r = []
10.times do |e|

Thread.new {
 @c = 1
 @c += @a
 r << [e, @c]
}
end
r
## [[3, 2], [1, 2], [2, 2], [0, 2], [5, 2], [6, 2], [7, 2], [8, 2], [9, 2], [4, 2]]

@a = 1
r = []
10.times do |e|

Thread.new {
 @c = 1
 puts @c
 @c += @a
 r << [e, @c]
}
end
r
## [[2, 2], [0, 2], [4, 3], [5, 4], [7, 5], [9, 6], [1, 7], [3, 8], [6, 9], [8, 10]]