2024年3月28日发(作者：校青曼)
本文由我司收集整编，推荐下载，如有疑问，请与我司联系
多线程C程序在OS X上比Linux慢得多。
I wrote this for an OS class assignment that I’ve already completed and handed in. I
posted this question yesterday, but due to “Academic Honesty” regulations I took it off
until after the submission deadline.
我为一个OS类作业写了这个，我已经完成并交了。我昨天发布了这个问题，但
由于“学术诚信”的规定，我在提交截止日期后才将其删除。
The object was to learn how to use critical sections. There is a data array with 100
monotonously increasing numbers, 0...99, and 40 threads that randomly swap two
elements 2,000,000 times each. Once a second a Checkergoes through and makes sure that
there is only one of each number (which means that no parallel access happened).
目的是学习如何使用关键部分。有一个带有100个单调递增数字的数据数组，
0…99和40个线程，每个线程随机交换两个元素200万次。每秒钟检查一次，确保
每个数字中只有一个(这意味着没有并行访问发生)。
Here were the Linux times:
以下是Linux时代:
real 0m5.102suser 0m5.087ssys 0m0.000s and the OS X times
OS X乘以
real 6m54.139suser 0m41.873ssys 6m43.792s I run a vagrant box with
ubuntu/trusty64 on the same machine that is running OS X. It is a quad-core i7 2.3Ghz (up
to 3.2Ghz) 2012 rMBP.
我在运行OS x的同一台机器上运行一个带有ubuntu/trusty64的移动盒子。它是一
个四核i7 2.3Ghz(最高3.2Ghz) 2012 rMBP。
If I understand correctly, sys is system overhead, which I have no control over, and
even then, 41s of user time suggests that perhaps the threads are running serially.
如果我理解正确的话，sys是系统开销，我无法控制系统开销，即使这样，41s的
用户时间也表明线程可能是连续运行的。
2024年3月28日发(作者：校青曼)
本文由我司收集整编，推荐下载，如有疑问，请与我司联系
多线程C程序在OS X上比Linux慢得多。
I wrote this for an OS class assignment that I’ve already completed and handed in. I
posted this question yesterday, but due to “Academic Honesty” regulations I took it off
until after the submission deadline.
我为一个OS类作业写了这个，我已经完成并交了。我昨天发布了这个问题，但
由于“学术诚信”的规定，我在提交截止日期后才将其删除。
The object was to learn how to use critical sections. There is a data array with 100
monotonously increasing numbers, 0...99, and 40 threads that randomly swap two
elements 2,000,000 times each. Once a second a Checkergoes through and makes sure that
there is only one of each number (which means that no parallel access happened).
目的是学习如何使用关键部分。有一个带有100个单调递增数字的数据数组，
0…99和40个线程，每个线程随机交换两个元素200万次。每秒钟检查一次，确保
每个数字中只有一个(这意味着没有并行访问发生)。
Here were the Linux times:
以下是Linux时代:
real 0m5.102suser 0m5.087ssys 0m0.000s and the OS X times
OS X乘以
real 6m54.139suser 0m41.873ssys 6m43.792s I run a vagrant box with
ubuntu/trusty64 on the same machine that is running OS X. It is a quad-core i7 2.3Ghz (up
to 3.2Ghz) 2012 rMBP.
我在运行OS x的同一台机器上运行一个带有ubuntu/trusty64的移动盒子。它是一
个四核i7 2.3Ghz(最高3.2Ghz) 2012 rMBP。
If I understand correctly, sys is system overhead, which I have no control over, and
even then, 41s of user time suggests that perhaps the threads are running serially.
如果我理解正确的话，sys是系统开销，我无法控制系统开销，即使这样，41s的
用户时间也表明线程可能是连续运行的。