Continuations - Under the Covers
summary
Implementation moves continuation frames into heap stack chunks and uses a lazy copy strategy plus return‑barriers so only new frames are memcopied back to the thread stack, avoiding full-stack copies. GC is extended to treat chunks as objects, allow background bitmap building and later compress chunks, cutting continuation storage by >50% (possibly ~70%). Result: virtual-thread context switching costs drop to near pointer-switch speeds, scales to millions of continuations, and integrates with OpenJDK/loom and JEP 444.
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chapters (9)
- 0:00Introduction to continuations
- 2:33Continuation API
- 4:58Thread state and blocking
- 7:23Stack management models
- 10:44Lazy frame copying
- 13:35GC challenges
- 16:06Stack chunk implementation
- 22:47Optimized suspension
- 30:11Performance and future goals
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