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How to determine whether a given Linux is 32 bit or 64 bit?

...wk '{print $2}' Note: you can have a 64-bit CPU with a 32-bit kernel installed. (as ysdx mentions in his/her own answer, "Nowadays, a system can be multiarch so it does not make sense anyway. You might want to find the default target of the compiler") ...
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How to calculate a time difference in C++

...turns the CPU time consumed by the program. So if the program is run in parallel the time returned by the function would be the accumulated of the time spent on all CPUs, rather than the time elapsed cplusplus.com/reference/ctime/clock – Ameer Jewdaki Aug 3 '1...
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Is gettimeofday() guaranteed to be of microsecond resolution?

I am porting a game, that was originally written for the Win32 API, to Linux (well, porting the OS X port of the Win32 port to Linux). ...
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马云、王健林为什么都看中了上海? - 资讯 - 清泛网 - 专注C/C++及内核技术

...”随着国家对于上海是“国际经济、金融、贸易中心”的定位,很多相关机构都陆续落地上海。到1995年,上海的外资金融机构数量已占全国27%,居全国首位。 经过25年的发展,上海国际金融中心的地位也得到了认可。据2014年...
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c/c++如何获取CPU的序列号? - C/C++ - 清泛网 - 专注C/C++及内核技术

c/c++如何获取CPU的序列号?获取CPU序列表的完整实例代码如下:#include "stdafx.h"#include <afx.h>CString GetCpuSerial(){unsigned long st1 = 0;un...获取CPU序列表的完整实例代码如下: #include "stdafx.h" #include <afx.h> CString GetCpuSerial() { unsigne...
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BIO与NIO、AIO的区别(这个容易理解) - 操作系统(内核) - 清泛网 - 专注C/C++及内核技术

...于事件驱动思想来完成的,其主要想解决的是BIO的大并发问题: 在使用同步I/O的网络应用中,如果要同时处理多个客户端请求,或是在客户端要同时和多个服务器进行通讯,就必须使用多线程来处理。也就是说,将每一个客户...
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How does BLAS get such extreme performance?

...e optimization. This boost significantly exceeds the second boost from parallelism and other hardware optimizations. By the way, most (or even all) of the high performance BLAS implementations are NOT implemented in Fortran. ATLAS is implemented in C. GotoBLAS/OpenBLAS is implemented in C and i...
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Android代码优化小技巧 - 更多技术 - 清泛网 - 专注C/C++及内核技术

...尽量避免创建不必要的对象,有下面一些例子来说明这个问题: 如果你需要返回一个String对象,并且你知道它最终会需要连接到一个StringBuffer,请修改你的实现方式,避免直接进行连接操作,应该采用创建一个临时对象来做...
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What does Python's eval() do?

...less until you find a need for it. It is used on sites like codepad.org to allow you to execute scripts in a test environment. eval() can also be used to execute highly-dynamic code, but you should make yourself fully aware of the security and performance risks before using it. ...
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What is the difference between user and kernel modes in operating systems?

... CPU instruction and reference any memory address. Kernel mode is generally reserved for the lowest-level, most trusted functions of the operating system. Crashes in kernel mode are catastrophic; they will halt the entire PC. User Mode In User mode, the executing code has no abili...