structured-coroutines-runtime/io.github.santimattius.structured.runtime/PoolSignal

PoolSignal

A heuristic hint derived from DispatcherMetrics. Sealed so more signals can be added later. Signals are hints, not proof: they say where to look, not what is wrong.

Example:

when (val signal = metrics.signals().firstOrNull()) {
    is PoolSignal.StarvationSuspected -> alert(signal.label)
    is PoolSignal.LongRunningSegment -> alert(signal.label)
    is PoolSignal.BacklogGrowing, is PoolSignal.PoolSaturated -> alert(signal.label)
    null -> Unit
}

Requires opting in to ExperimentalStructuredCoroutines.

Inheritors

Types

BacklogGrowing

class BacklogGrowing(val label: String, val samples: Int, val from: Long, val to: Long) : PoolSignal

pending never decreased across the last samples pool samples and rose from from to to. Produced by List<TraceEvent.PoolSample>.signals.

LongRunningSegment

class LongRunningSegment(val label: String, val longestRun: Duration) : PoolSignal

A single segment ran for longestRun, at or above the threshold.

PoolSaturated

class PoolSaturated(val label: String, val parallelism: Int, val samples: Int) : PoolSignal

Across the last samples pool samples the dispatcher ran at its parallelism limit while work was waiting. Produced by List<TraceEvent.PoolSample>.signals.

StarvationSuspected

class StarvationSuspected(val label: String, val queueDelayP95: Duration, val pending: Long) : PoolSignal

Work is waiting and waited long: pending is positive and the queue-delay p95 (queueDelayP95, a bucket upper bound) reached the threshold. pending can overcount, see DispatcherMetrics.pending.

Properties

label

abstract val label: String

Label of the dispatcher the signal is about.

PoolSignal

See also

Inheritors

Types

Properties