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Rare Earth Juejin Tech Community

Aug 29, 2022 · Mobile Development

Optimizing iOS App Startup by Adjusting GCD Queue QoS and Reducing Main Thread Preemption

By analyzing thread preemption on low‑end iPhones, this article demonstrates how selecting appropriate GCD queue QoS levels—favoring Utility or Background over User‑Initiated—reduces main‑thread contention, improves launch screen rendering by ~100 ms, and accelerates message list first‑load by up to 1.5 s without altering business logic.

QoSconcurrencygcd

0 likes · 10 min read

Optimizing iOS App Startup by Adjusting GCD Queue QoS and Reducing Main Thread Preemption

IT Services Circle

Feb 6, 2022 · Fundamentals

Measuring Water with Two Cups: Logical Analysis and C++ Implementation

This article explains the classic water‑jug interview problem using two cups of 9 L and 15 L, derives the reachable volumes via greatest‑common‑divisor logic, and provides complete C++ code to determine feasibility and output the pouring steps for any target volume.

C++algorithmgcd

0 likes · 6 min read

Measuring Water with Two Cups: Logical Analysis and C++ Implementation

Sohu Tech Products

Nov 25, 2020 · Mobile Development

Deep Dive into GCD Dispatch Queues, sync/async Behavior, and RunLoop Interaction on iOS

This article explores the intricacies of Grand Central Dispatch on iOS, debunking common misconceptions about main thread and main queue execution, analyzing the internal handling of synchronous tasks, and demonstrating how run‑loop activation influences queue‑thread relationships through a series of code experiments.

AsyncMultithreadingRunLoop

0 likes · 14 min read

Deep Dive into GCD Dispatch Queues, sync/async Behavior, and RunLoop Interaction on iOS

Amap Tech

Feb 27, 2020 · Mobile Development

Common Misunderstandings and Pitfalls in iOS Development – Foundation, UIKit, GCD and Best Practices

The article clarifies frequent iOS development misconceptions—from unnecessary observer removal and deprecated NSUserDefaults synchronization to block retain‑cycle tricks, responder‑chain versus hit‑testing differences, GCD queue optimizations, safe main‑queue detection, and proper cancellation of dispatch blocks—offering practical code guidance.

Memory ManagementObjective-CUIKit

0 likes · 17 min read

Common Misunderstandings and Pitfalls in iOS Development – Foundation, UIKit, GCD and Best Practices

JD Retail Technology

Jan 10, 2020 · Mobile Development

Understanding iOS Timers: NSTimer, CADisplayLink, and GCD Dispatch Sources

This article explains the three main iOS timer mechanisms—NSTimer, CADisplayLink, and GCD dispatch sources—detailing their creation methods, differences, common pitfalls such as RunLoop mode and thread issues, and practical solutions for accurate scheduling.

CADisplayLinkNSTimerTimer

0 likes · 14 min read

Understanding iOS Timers: NSTimer, CADisplayLink, and GCD Dispatch Sources

Qunar Tech Salon

Jul 27, 2017 · Mobile Development

Deep iOS Performance Optimization: Time Complexity, GCD, Thread Monitoring, and Method Hooking

This article explains how to analyze and improve iOS app performance by understanding time‑complexity impacts, leveraging GCD for asynchronous work, preventing thread explosion, optimizing I/O and memory usage, and using low‑level techniques such as stack tracing, symbolication, and objc_msgSend hooking.

MethodHookingThreadMonitoringTimeComplexity

0 likes · 22 min read

Deep iOS Performance Optimization: Time Complexity, GCD, Thread Monitoring, and Method Hooking