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stream: use the ring buffer for WHATWG stream request queues - #64431

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mcollina:webstream-perf-round8
Jul 13, 2026
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stream: use the ring buffer for WHATWG stream request queues#64431
nodejs-github-bot merged 1 commit into
nodejs:mainfrom
mcollina:webstream-perf-round8

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@mcollinamcollina commented Jul 11, 2026

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The [[queue]] backing the controllers is now a ring buffer, but the read/write request queues (readRequests, readIntoRequests, writeRequests) were left as plain arrays consumed with ArrayPrototypeShift. Back them with the same Queue, materialized lazily from the shared empty queue so acquiring a reader or constructing a writer allocates no request storage until a read/write parks.

pipe-to: +4.7% to +9.4% (all 16 configs, ***)
readable-read type=byob: +2.3% (**)
parked reader.read() loop: +15%, writer.write() loop: +11% (local harness)

Follow-up to #64312.

@nodejs-github-botnodejs-github-bot added needs-ci PRs that need a full CI run. web streams labels Jul 11, 2026
@mcollina
mcollinaforce-pushed the webstream-perf-round8 branch from e8dd939 to e203888CompareJuly 11, 2026 20:48
@mertcanaltin

mertcanaltin commented Jul 11, 2026

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Need a signature for first commit message.

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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.23%. Comparing base (8a3b11c) to head (e65f9be).
⚠️ Report is 17 commits behind head on main.

Additional details and impacted files
@@ Coverage Diff @@## main #64431 +/- ##
==========================================
- Coverage 90.24% 90.23% -0.01% 
==========================================
Files 741 741 Lines 241384 241391 +7 Branches 45480 45487 +7 ==========================================
- Hits 217844 217827 -17 - Misses 15097 15129 +32 + Partials 8443 8435 -8 
Files with missing linesCoverage Δ
lib/internal/webstreams/readablestream.js98.19% <100.00%> (+<0.01%)⬆️
lib/internal/webstreams/util.js97.71% <100.00%> (+<0.01%)⬆️
lib/internal/webstreams/writablestream.js99.50% <100.00%> (+<0.01%)⬆️

... and 40 files with indirect coverage changes

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  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
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The [[queue]] backing the controllers became a ring buffer, but the
read and write request queues (readRequests, readIntoRequests,
writeRequests) were left as plain arrays consumed with
ArrayPrototypeShift, which is O(n) and, even for the single pending
request of the await-each regime, far slower than an indexed head
advance. Back them with the same Queue, materialized lazily from the
shared empty queue so acquiring a reader or constructing a writer
allocates no request storage until a read or write actually parks.
pipe-to: +4.7% to +9.4% (all 16 configs, ***)
readable-read type=byob: +2.3% (**)
parked read loop: +15%, write loop: +11% (local harness)
Follow-up to nodejs#64312.
Signed-off-by: Matteo Collina <hello@matteocollina.com>
@mcollina
mcollinaforce-pushed the webstream-perf-round8 branch from e203888 to e65f9beCompareJuly 12, 2026 10:48
@mcollinamcollina added the request-ci Add this label to start a Jenkins CI on a PR. label Jul 12, 2026
@github-actionsgithub-actionsBot removed the request-ci Add this label to start a Jenkins CI on a PR. label Jul 12, 2026
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mcollina requested a review from aduh95July 13, 2026 07:47
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Benchmark GHA (webstreams): https://github.com/nodejs/node/actions/runs/29233460863

Results

[!WARNING]
Do not take GHA benchmark results as face value, always confirm them
using a dedicated machine, e.g. Jenkins CI.

Benchmark results:

 confidence improvement accuracy (*) (**) (***)
webstreams/creation.js kind='ReadableStream.tee' n=50000 0.64 % ±6.98% ±9.19% ±11.80%
webstreams/creation.js kind='ReadableStream' n=50000 0.75 % ±7.98% ±10.51% ±13.49%
webstreams/creation.js kind='ReadableStreamBYOBReader' n=50000 3.30 % ±6.13% ±8.08% ±10.36%
webstreams/creation.js kind='ReadableStreamDefaultReader' n=50000 1.63 % ±7.61% ±10.03% ±12.86%
webstreams/creation.js kind='TransformStream' n=50000 -0.51 % ±7.00% ±9.23% ±11.84%
webstreams/creation.js kind='WritableStream' n=50000 -0.63 % ±7.84% ±10.33% ±13.26%
webstreams/js_transfer.js n=10000 payload='ReadableStream' -0.43 % ±9.64% ±12.71% ±16.30%
webstreams/js_transfer.js n=10000 payload='TransformStream' 0.77 % ±9.28% ±12.23% ±15.70%
webstreams/js_transfer.js n=10000 payload='WritableStream' 0.83 % ±9.45% ±12.46% ±15.98%
webstreams/pipe-to.js highWaterMarkW=1024 highWaterMarkR=1024 n=500000 * 7.38 % ±7.34% ±9.68% ±12.42%
webstreams/pipe-to.js highWaterMarkW=1024 highWaterMarkR=2048 n=500000 * 8.21 % ±7.21% ±9.51% ±12.20%
webstreams/pipe-to.js highWaterMarkW=1024 highWaterMarkR=4096 n=500000 * 7.71 % ±7.29% ±9.61% ±12.33%
webstreams/pipe-to.js highWaterMarkW=1024 highWaterMarkR=512 n=500000 7.03 % ±7.25% ±9.56% ±12.27%
webstreams/pipe-to.js highWaterMarkW=2048 highWaterMarkR=1024 n=500000 * 7.39 % ±7.26% ±9.57% ±12.28%
webstreams/pipe-to.js highWaterMarkW=2048 highWaterMarkR=2048 n=500000 * 8.57 % ±7.26% ±9.57% ±12.28%
webstreams/pipe-to.js highWaterMarkW=2048 highWaterMarkR=4096 n=500000 * 7.49 % ±7.15% ±9.43% ±12.10%
webstreams/pipe-to.js highWaterMarkW=2048 highWaterMarkR=512 n=500000 * 7.74 % ±7.29% ±9.61% ±12.33%
webstreams/pipe-to.js highWaterMarkW=4096 highWaterMarkR=1024 n=500000 * 7.58 % ±7.30% ±9.62% ±12.35%
webstreams/pipe-to.js highWaterMarkW=4096 highWaterMarkR=2048 n=500000 * 9.04 % ±7.43% ±9.80% ±12.57%
webstreams/pipe-to.js highWaterMarkW=4096 highWaterMarkR=4096 n=500000 * 9.27 % ±7.45% ±9.82% ±12.61%
webstreams/pipe-to.js highWaterMarkW=4096 highWaterMarkR=512 n=500000 * 8.51 % ±7.42% ±9.78% ±12.55%
webstreams/pipe-to.js highWaterMarkW=512 highWaterMarkR=1024 n=500000 * 7.52 % ±7.21% ±9.51% ±12.20%
webstreams/pipe-to.js highWaterMarkW=512 highWaterMarkR=2048 n=500000 * 8.04 % ±7.35% ±9.68% ±12.42%
webstreams/pipe-to.js highWaterMarkW=512 highWaterMarkR=4096 n=500000 * 8.19 % ±7.32% ±9.64% ±12.38%
webstreams/pipe-to.js highWaterMarkW=512 highWaterMarkR=512 n=500000 6.34 % ±7.18% ±9.46% ±12.14%
webstreams/readable-async-iterator.js type='bytes' n=100000 4.92 % ±9.89% ±13.04% ±16.73%
webstreams/readable-async-iterator.js type='normal' n=100000 0.64 % ±7.19% ±9.47% ±12.15%
webstreams/readable-read-buffered.js bufferSize=1 n=100000 -0.84 % ±6.44% ±8.48% ±10.89%
webstreams/readable-read-buffered.js bufferSize=10 n=100000 -0.49 % ±5.97% ±7.87% ±10.10%
webstreams/readable-read-buffered.js bufferSize=100 n=100000 -1.56 % ±6.02% ±7.94% ±10.18%
webstreams/readable-read-buffered.js bufferSize=1000 n=100000 -0.08 % ±6.24% ±8.23% ±10.56%
webstreams/readable-read.js type='byob' n=100000 0.48 % ±7.52% ±9.91% ±12.72%
webstreams/readable-read.js type='normal' n=100000 ** 7.82 % ±5.83% ±7.69% ±9.87%
Be aware that when doing many comparisons the risk of a false-positive
result increases. In this case, there are 33 comparisons, you can thus
expect the following amount of false-positive results:
1.65 false positives, when considering a 5% risk acceptance (*, **, ***),
0.33 false positives, when considering a 1% risk acceptance (**, ***),
0.03 false positives, when considering a 0.1% risk acceptance (***)

[!WARNING]
Do not take GHA benchmark results as face value, always confirm them
using a dedicated machine, e.g. Jenkins CI.

@aduh95aduh95 added author ready PRs that have at least one approval, no pending requests for changes, and a CI started. commit-queue Add this label to land a pull request using GitHub Actions. labels Jul 13, 2026
@nodejs-github-botnodejs-github-bot removed the commit-queue Add this label to land a pull request using GitHub Actions. label Jul 13, 2026
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nodejs-github-bot merged commit ace91de into nodejs:mainJul 13, 2026
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@mcollina
mcollina deleted the webstream-perf-round8 branch July 15, 2026 15:32
aduh95 pushed a commit that referenced this pull request Jul 21, 2026
The [[queue]] backing the controllers became a ring buffer, but the
read and write request queues (readRequests, readIntoRequests,
writeRequests) were left as plain arrays consumed with
ArrayPrototypeShift, which is O(n) and, even for the single pending
request of the await-each regime, far slower than an indexed head
advance. Back them with the same Queue, materialized lazily from the
shared empty queue so acquiring a reader or constructing a writer
allocates no request storage until a read or write actually parks.
pipe-to: +4.7% to +9.4% (all 16 configs, ***)
readable-read type=byob: +2.3% (**)
parked read loop: +15%, write loop: +11% (local harness)
Follow-up to #64312.
Signed-off-by: Matteo Collina <hello@matteocollina.com>
PR-URL: #64431
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
aduh95 pushed a commit that referenced this pull request Jul 21, 2026
The [[queue]] backing the controllers became a ring buffer, but the
read and write request queues (readRequests, readIntoRequests,
writeRequests) were left as plain arrays consumed with
ArrayPrototypeShift, which is O(n) and, even for the single pending
request of the await-each regime, far slower than an indexed head
advance. Back them with the same Queue, materialized lazily from the
shared empty queue so acquiring a reader or constructing a writer
allocates no request storage until a read or write actually parks.
pipe-to: +4.7% to +9.4% (all 16 configs, ***)
readable-read type=byob: +2.3% (**)
parked read loop: +15%, write loop: +11% (local harness)
Follow-up to #64312.
Signed-off-by: Matteo Collina <hello@matteocollina.com>
PR-URL: #64431
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
RafaelGSS pushed a commit that referenced this pull request Jul 29, 2026
The [[queue]] backing the controllers became a ring buffer, but the
read and write request queues (readRequests, readIntoRequests,
writeRequests) were left as plain arrays consumed with
ArrayPrototypeShift, which is O(n) and, even for the single pending
request of the await-each regime, far slower than an indexed head
advance. Back them with the same Queue, materialized lazily from the
shared empty queue so acquiring a reader or constructing a writer
allocates no request storage until a read or write actually parks.
pipe-to: +4.7% to +9.4% (all 16 configs, ***)
readable-read type=byob: +2.3% (**)
parked read loop: +15%, write loop: +11% (local harness)
Follow-up to #64312.
Signed-off-by: Matteo Collina <hello@matteocollina.com>
PR-URL: #64431
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
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