stream: add fast paths for webstreams read and pipeTo#61807
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mcollina wants to merge 1 commit intonodejs:mainfrom
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stream: add fast paths for webstreams read and pipeTo#61807mcollina wants to merge 1 commit intonodejs:mainfrom
mcollina wants to merge 1 commit intonodejs:mainfrom
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Qard
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Codecov Report❌ Patch coverage is
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## main #61807 +/- ##
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- Coverage 89.75% 89.71% -0.05%
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Files 674 675 +1
Lines 204416 204884 +468
Branches 39285 39377 +92
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+ Hits 183472 183807 +335
- Misses 13227 13338 +111
- Partials 7717 7739 +22
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jasnell
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Comparing batchCount to hwm is only valid if controller[kState].sizeAlgorithm is the default size algorithm (i.e. each chunk has size 1). I don't think we can assume that?
We should add a test that uses a custom size algorithm.
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Why || 1? An HWM of 0 is valid.
Add internal fast paths to improve webstreams performance without changing the public API or breaking spec compliance. 1. ReadableStreamDefaultReader.read() fast path: When data is already buffered in the controller's queue, return PromiseResolve() directly without creating a DefaultReadRequest object. This is spec-compliant because read() returns a Promise, and resolved promises still run callbacks in the microtask queue. 2. pipeTo() batch read fast path: When data is buffered, batch reads directly from the controller queue up to highWaterMark without creating PipeToReadableStreamReadRequest objects per chunk. Respects backpressure by checking desiredSize after each write. Benchmark results: - pipeTo: ~11% faster (***) - buffered read(): ~17-20% faster (***) Co-Authored-By: Malte Ubl <malte@vercel.com>
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Add internal fast paths to improve webstreams performance without changing the public API or breaking spec compliance.
ReadableStreamDefaultReader.read() fast path: When data is already buffered in the controller's queue, return PromiseResolve() directly without creating a DefaultReadRequest object. This is spec-compliant because read() returns a Promise, and resolved promises still run callbacks in the microtask queue.
pipeTo() batch read fast path: When data is buffered, batch reads directly from the controller queue up to highWaterMark without creating PipeToReadableStreamReadRequest objects per chunk. Respects backpressure by checking desiredSize after each write.
Benchmark results:
This was done in partnership with Vercel to improve the performance of React and Next.js, and from a conversation on X with @cramforce.