Skip to content

Commit 41f0a2e

Browse files
rahul2393rahul2393
authored
feat(grpc-gcp): move scale-up to background worker (#14206)
With dynamic scaling enabled, **maybeDynamicUpscale()** ran synchronously on the caller thread during channel selection, before the stream was counted. It scaled on the pool-wide average only, one channel per trigger, with no cooldown — so a burst could add channels one RPC at a time while the caller waited on channel construction, and a single hot channel never triggered growth if the average stayed low. **Change** - Signal after accounting. **activeStreamsCountIncr()** evaluates the trigger once the stream is reserved: the selected channel above maxRpcPerChannel, or the pool average above it, signals scale-up. Channel selection itself no longer scales. - Single background worker. A one-slot signal (AtomicBoolean pending/running) coalesces bursts; the worker runs on the shared background executor, loops while signals arrive, and catches **Throwable** so one failure can't stop future scale-ups. The scale-down timer body gets the same guard. - Bounded, load-sized growth. Desired size = **ceil(totalActiveStreams / midpoint(minRpc, maxRpc))**, added channels capped at **maxScaleUpPercent** of the active pool (floor 2) and by maxSize. A scaleUpCooldown (default 10s) is claimed before channel construction so signals arriving mid-build are throttled. READY channels awaiting shutdown are reused before new ones are built. - Construction outside the lock. Delegate channels are built without holding the pool monitor; publication rechecks shutdown and headroom under the lock and closes surplus channels. - Inactive channels excluded from round-robin, fallback, extrema (getMin/MaxActiveStreams) and picker scans; the legacy watermark scale-up no longer computes getMaxActiveStreams() on the hot path when dynamic scaling is enabled. - Shutdown ordering: shuttingDown is set under the pool lock as the first step of shutdown()/shutdownNow(), so a channel cannot be published after shutdown begins. removedChannelRefs is now a concurrent set, safe for the worker and the unsynchronized readers (isShutdown, isTerminated, awaitTermination, stats logging).
1 parent d7e2be2 commit 41f0a2e

7 files changed

Lines changed: 912 additions & 86 deletions

File tree

0 commit comments

Comments
 (0)