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Is a LINQ statement faster than a 'foreach' loop?
...parison.
Re PLINQ; parallelism may reduce the elapsed time, but the total CPU time will usually increase a little due to the overheads of thread management etc.
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C语言结构体里的成员数组和指针 - C/C++ - 清泛网 - 专注C/C++及内核技术
...问0x4的内存地址，不crash才怪。于是，你一定会有如下的问题：
1）为什么不是 13行if语句出错？f.a被初始化为空了嘛，用空指针访问成员变量为什么不crash？
2）为什么会访问到了0x4的地址？靠，4是怎么出来的？
3）代码中的...
What exactly are “spin-locks”?
...lly short, because your thread now has to wait for a preemption to receive CPU time again.
Besides, kernel objects are not available in every state of the kernel, such as in an interrupt handler or when paging is not available etc.
Spinlocks don't cause preemption but wait in a loop ("spin") till th...
What's the Android ADB shell “dumpsys” tool and what are its benefits?
...m information in a simple string representation.
Possibility to use dumped CPU, RAM, Battery, storage stats for a
pretty charts, which will allow you to check how your application
affects the overall device!
What information can we retrieve from dumpsys shell command and how we can use it
If you ...
那些我印象深刻的建议和教诲 - 杂谈 - 清泛网 - 专注C/C++及内核技术
...弱点，真是人生的一大考验。有些人采取鸵鸟政策，假装问题不存在；有些人一看苗头不对就转移，避开心虚；还有些人打肿脸充胖子，掩盖心虚。总之，都是在躲，都是不健康的应对。
真正健康的方式是什么？是努力戒除情...
How to make execution pause, sleep, wait for X seconds in R?
...(x)
{
p1 <- proc.time()
Sys.sleep(x)
proc.time() - p1 # The cpu usage should be negligible
}
testit(3.7)
Yielding
> testit(3.7)
user system elapsed
0.000 0.000 3.704
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What is the purpose of XORing a register with itself? [duplicate]
...it the fastest way it knows. A bit operation like XOR might take only one CPU cycle, whereas a copy (from one register to another) can take a small handful.
Often compiler writers will even have different behaviors given different target CPU architectures.
...
裁员！裁员！创业者们的2016“寒冬大逃杀” - 资讯 - 清泛网 - 专注IT技能提升
...候，“什么时候盈利”忽然成了几乎每个投资人都会问的问题，但在之前的三轮融资都没有人提过。当时大家关心的都是订单量、GMV和增速。
“无论公司当下有没有收入，从财务模型上看，都是要在收敛的、亏损是在变小的。...
John Carmack's Unusual Fast Inverse Square Root (Quake III)
...ng result, until required accuracy is met. This is exactly how it works in CPU/FPU! But it seems that only one iteration was enough, which was also a blessing for the speed. CPU/FPU does as many iterations as needed to reach the accuracy for the floating point number in which the result is stored an...
How do you determine the ideal buffer size when using FileInputStream?
...mum buffer size is related to a number of things: file system block size, CPU cache size and cache latency.
Most file systems are configured to use block sizes of 4096 or 8192. In theory, if you configure your buffer size so you are reading a few bytes more than the disk block, the operations wit...