First, I gonna post my test result with some code: //test the peformance of the <normal operation> and the <shift operation>. class ShiftOperation { public static void main(String[] args) { long startTime1 = System.nanoTime(); for(long i = 0;…

输入 sudo apt update && sudo apt full-upgrade…

现如今移动设备也早已经进入了多核心 CPU 时代,并且随着时间的推移,CPU 的核心数只会增加不会减少.而作为软件开发者,我们需要做的就是尽可能地提高应用的并发性,来充分利用这些多核心 CPU 的性能.在 iOS 开发中,我们主要可以通过 Operation Queues.Dispatch Queues 和 Dispatch Sources 来提高应用的并发性.本文将主要介绍 Operation Queues 的相关知识,另外两个属于 Grand Central Dispatch(以下正文简称…

FIELD OF THE INVENTION The present invention is related to computing systems, and more particularly to a system and method for adjusting to changes in processor performance. BACKGROUND INFORMATION Designers of mobile computing platforms are faced wit…

https://datatracker.ietf.org/doc/rfc8684/?include_text=1 TCP Extensions for Multipath Operation with Multiple AddressesRFC 8684   Document Type   RFC - Proposed Standard (March 2020; No errata) Obsoletes RFC 6824 Was draft-ietf-mptcp-rfc6824bis (mptc…

这篇博客来源于今年的一个面试题,当我们使用SDWebImgae框架中的sd_setImageWithURL: placeholderImage:方法在tableView或者collectionView里面下载图片的时候,滑动tableView发现它会优先下载展示在屏幕上的cell里面的图片,如果你不用SDWebImage框架如何实现? 我iOS开发到现在大致是实习差不多一年,正式工作八九个月的样子,在此之前虽然经常使用诸如SDWebImgae.AFNetworking.MJRefresh.MJE…

http://queue.acm.org/detail.cfm?id=1854041 The July/August issue of acmqueue is out now acmqueue is free for ACM professional members. Non-members can purchase an annual subscription for $19.99 or a single issue for $6.99. Download the app from iTune…

Stephen Toub Download the Code Sample Asynchronous programming has long been the realm of only the most skilled and masochistic of developers-those with the time, inclination and mental capacity to reason about callback after callback of non-linear c…

1. 进程和线程 1.1 进程 进程:正在运行的应用程序叫进程 进程之间都是独立的,运行在专用且受保护的内存空间中 两个进程之间无法通讯 通俗的理解,手机上同时开启了两个App.这两个App肯定是在不同的进程中的.所以这两个App之间是独立的,内存中的数据不能互相窜来窜去,两个App之间也没有办法进行通讯. 两个App之间没有办法进行通讯?我说的是正常情况下.当然还是有不正常情况啊,例如使用iOS提供的极少数的几种进程间通讯的工具. 1.2 线程 线程:进程想要执行任务,必须要有线程,每个进程至…

Download source - 93.5 KB Introduction Though performance blocking and sluggishness are the tailbacks for any application, we can easily overcome these bottlenecks by using asynchronous programming. But old-style practice for asynchronous programming…