WeChat Client Technology Team

Jun 17, 2021 · Mobile Development

Why Setting a Low Thread Priority on Android Can Crash the Main Thread

An in‑depth investigation reveals that calling Thread.start() before setPriority() on Android can unintentionally lower the main thread’s priority and increase TimerSlack, causing sleep/wait delays, video stutter, and a major WeChat outage, with root causes traced to timing issues and WebView initialization.