Synchronous Execution is an Illusion, Depending on Who's Looking | Michael Awoniran | SysConf 2026

When engineers write synchronous code, every line appears to run sequentially as written, and that is true only from the engineer’s perspective. However, as we go down the stack, there are lots of nuances to note. In this session, Michael explores what happens when code is executed through four lenses: the engineer, the language runtime, the OS, and the CPU. Each layer has its own view of execution; runs that look sequential are often being scheduled, paused, resumed, interrupted or even reordered.