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Why does the order of the loops affect performance when iterating over a 2D array?
...2]
x[0][3]
x[1][0] etc...
Meaning that you're hitting them all in order. Now look at the 1st version. You're doing:
x[0][0]
x[1][0]
x[2][0]
...
Volatile vs. Interlocked vs. lock
...it check against a CPU register (e.g. EAX because that was what m_Var was fetched into from the very beginning) instead of issuing another read to the memory location of m_Var (this may be cached - we don't know and don't care and that's the point of cache coherency of x86/x64). All the posts earlie...
MySQL主从服务器数据一致性的核对与修复 - 数据库(内核) - 清泛网 - 专注C/...
...性的核对与修复我上一次遇到MySQL主从服务器数据一致性问题，想想是几年前的事情了，还依稀记得当时惊慌失措的情景，好在最后借助Maatkit解决了问题。几年...我上一次遇到MySQL主从服务器数据一致性问题，想想是几年前的事...
Optimal number of threads per core
...
If your threads don't do I/O, synchronization, etc., and there's nothing else running, 1 thread per core will get you the best performance. However that very likely not the case. Adding more threads usually helps, but after some point, they cause some performance degradat...
Why use sprintf function in PHP?
...NTO `Users` SET `user`='%s',`password`='%s',`realname`='%s';", $username, $passwd_hash, $realname);
This method does of course have other uses, such as when printing output as HTML, etc.
Edit: For security reasons, when using a technique as above you must sanitise all input variables with mysql_r...
What is a “thread” (really)?
...is loaded in the processor core, the thread is running. The processor is fetching instructions demanded by the thread and updating the thread registers. When a context switch is needed, the processor saves this set of register values into memory and loads a set belonging to a different thread, typ...
OceanBase使用libeasy原理源码分析：客户端 - 数据库(内核) - 清泛网 - 专...
..._list_t session_list_node;
//为了快速根据packet id定位到发送队列中的session，将session加入到发送队列中时，同时，将其加入到一个hash表中，hash表采用链表的方式将同一个bucket的元素连接起来，
//链表元素就是easy_ha...
How to send a correct authorization header for basic authentication
...
You can include the user and password as part of the URL:
http://user:passwd@www.server.com/index.html
see this URL, for more
HTTP Basic Authentication credentials passed in URL and encryption
of course, you'll need the username password, it's not 'Basic hashstring.
hope this helps...
...
What does $$ mean in the shell?
... as root and I create /tmp/yourprogname13395 as a symlink pointing to /etc/passwd -- and you write into it.
This is a bad thing to be doing in a shell script. If you're going to use a temporary file for something, you ought to be using a better language which will at least let you add the "exclusiv...
Programmatically find the number of cores on a machine
...umCPU = sysconf(_SC_NPROCESSORS_ONLN);
FreeBSD, MacOS X, NetBSD, OpenBSD, etc.
int mib[4];
int numCPU;
std::size_t len = sizeof(numCPU);
/* set the mib for hw.ncpu */
mib[0] = CTL_HW;
mib[1] = HW_AVAILCPU; // alternatively, try HW_NCPU;
/* get the number of CPUs from the system */
sysctl(mib, ...