Log when active streams reaches and drops below max concurrent streams #974
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Lukasa
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Sep 25, 2020
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One note about calculating max concurrent streams.
Sources/GRPC/GRPCIdleHandler.swift
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| }, uniquingKeysWith: { a, _ in a }) | ||
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| let maxConcurrentStreams = settings.first(where: { $0.parameter == .maxConcurrentStreams }) |
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A quick FYI: if there are multiple instances of a setting in a HTTP/2 settings frame, the last instance of the setting is the one that counts. HTTP2Settings is a RandomAccessCollection so you can do reversed() for free.
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Oh, good catch. Thanks!
Motivation: Reaching max concurrent streams will cause frames on additional streams to be buffered, and can therefore see increased latency. Observing this is difficult. Modifications: - Log any changes in HTTP/2 settings, not just the initial settings - Add a warning log when our active stream count matches max concurrent streams - Add a notice log when our stream count drops below max concurrent streams Result: Better observability when we get close to max concurrent streams.
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Lukasa
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Motivation:
Reaching max concurrent streams will cause frames on additional streams
to be buffered, and can therefore see increased latency. Observing this
is difficult.
Modifications:
streams
streams
Result:
Better observability when we get close to max concurrent streams.