src: use validate_ascii_with_errors for buffer.isAscii by ChALkeR · Pull Request #61122 · nodejs/node

ChALkeR · 2025-12-19T09:36:22Z

Tracking: #61041

Don't expect buffer.isAscii common-case to be ASCII, as that's exposed as a public API for checks.
The error version has better performance on non-ascii as it returns early, which could easily be e.g. >10x.

Refs: #46271 (comment),

But somehow the _errors version is also faster on ASCII, which was supposed to be a common case for validate_ascii?
I'm not sure what's up, might be a simdutf bug? cc @lemire

On another note: v8 is also likely using validate_ascii incorrectly

buffer.isAscii perf:

main:

Test	Size	Throughput	Mean Time
Latin lipsum (ASCII)	84.902 KiB	105.08 GiB/s	0.001 ms
Arabic lipsum	79.771 KiB	103.88 GiB/s	0.001 ms
Chinese lipsum	68.203 KiB	101.78 GiB/s	0.001 ms

PR

Test	Size	Throughput	Mean Time
Latin lipsum (ASCII)	84.902 KiB	117.97 GiB/s	0.001 ms
Arabic lipsum	79.771 KiB	1836.47 GiB/s	0.000 ms
Chinese lipsum	68.203 KiB	1564.76 GiB/s	0.000 ms

codecov · 2025-12-19T11:09:53Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.75%. Comparing base (04946a7) to head (f11c0ab).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #61122      +/-   ##
==========================================
+ Coverage   89.73%   89.75%   +0.01%     
==========================================
  Files         675      675              
  Lines      204648   204649       +1     
  Branches    39330    39326       -4     
==========================================
+ Hits       183651   183681      +30     
+ Misses      13282    13251      -31     
- Partials     7715     7717       +2

Files with missing lines	Coverage Δ
src/node_buffer.cc	`68.01% <100.00%> (+0.03%)`	⬆️

... and 45 files with indirect coverage changes

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
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lemire

Thanks for the ping.

nodejs-github-bot · 2026-01-17T18:54:36Z

CI: https://ci.nodejs.org/job/node-test-pull-request/70860/

gurgunday

lgtm

nodejs-github-bot · 2026-01-27T14:22:51Z

CI: https://ci.nodejs.org/job/node-test-pull-request/71068/

nodejs-github-bot · 2026-01-31T23:05:56Z

CI: https://ci.nodejs.org/job/node-test-pull-request/71146/

nodejs-github-bot · 2026-02-05T14:20:48Z

CI: https://ci.nodejs.org/job/node-test-pull-request/71207/

gurgunday · 2026-02-10T20:06:35Z

Should we just merge this? I can't restart the macOS CI

nodejs-github-bot · 2026-02-10T20:42:11Z

CI: https://ci.nodejs.org/job/node-test-pull-request/71299/

nodejs-github-bot · 2026-02-11T00:49:28Z

Commit Queue failed

- Loading data for nodejs/node/pull/61122
✔  Done loading data for nodejs/node/pull/61122
----------------------------------- PR info ------------------------------------
Title      src: use validate_ascii_with_errors for buffer.isAscii (#61122)
Author     Nikita Skovoroda <chalkerx@gmail.com> (@ChALkeR)
Branch     ChALkeR:chalker/ascii/is/0 -> nodejs:main
Labels     buffer, c++, author ready, needs-ci
Commits    1
 - src: use validate_ascii_with_errors instead of validate_ascii
Committers 1
 - Nikita Skovoroda <chalkerx@gmail.com>
PR-URL: https://github.com/nodejs/node/pull/61122
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Daniel Lemire <daniel@lemire.me>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Gürgün Dayıoğlu <hey@gurgun.day>
------------------------------ Generated metadata ------------------------------
PR-URL: https://github.com/nodejs/node/pull/61122
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Daniel Lemire <daniel@lemire.me>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Gürgün Dayıoğlu <hey@gurgun.day>
--------------------------------------------------------------------------------
   ℹ  This PR was created on Fri, 19 Dec 2025 09:36:22 GMT
   ✔  Approvals: 4
   ✔  - Colin Ihrig (@cjihrig): https://github.com/nodejs/node/pull/61122#pullrequestreview-3599469348
   ✔  - Daniel Lemire (@lemire): https://github.com/nodejs/node/pull/61122#pullrequestreview-3600703637
   ✔  - Rafael Gonzaga (@RafaelGSS) (TSC): https://github.com/nodejs/node/pull/61122#pullrequestreview-3674328458
   ✔  - Gürgün Dayıoğlu (@gurgunday): https://github.com/nodejs/node/pull/61122#pullrequestreview-3708188048
   ✘  Last GitHub CI failed
   ℹ  Last Full PR CI on 2026-02-10T20:42:11Z: https://ci.nodejs.org/job/node-test-pull-request/71299/
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- Querying failures of job/node-test-commit/85408/
✔  Data downloaded
   ✘  1 failure(s) on the last Jenkins CI run
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   ✔  Aborted `git node land` session in /home/runner/work/node/node/.ncu

https://github.com/nodejs/node/actions/runs/21888296181

ChALkeR · 2026-02-11T00:54:20Z

Jenkins CI was fine and didn't need to be restarted (but it apparently does now)
GH CI is stuck, who can restart it?

nodejs-github-bot · 2026-02-11T01:00:33Z

CI: https://ci.nodejs.org/job/node-test-pull-request/71301/

nodejs-github-bot · 2026-02-11T03:43:31Z

CI: https://ci.nodejs.org/job/node-test-pull-request/71303/

nodejs-github-bot · 2026-02-11T08:43:10Z

Commit Queue failed

- Loading data for nodejs/node/pull/61122
✔  Done loading data for nodejs/node/pull/61122
----------------------------------- PR info ------------------------------------
Title      src: use validate_ascii_with_errors for buffer.isAscii (#61122)
Author     Nikita Skovoroda <chalkerx@gmail.com> (@ChALkeR)
Branch     ChALkeR:chalker/ascii/is/0 -> nodejs:main
Labels     buffer, c++, author ready, needs-ci
Commits    1
 - src: use validate_ascii_with_errors instead of validate_ascii
Committers 1
 - Nikita Skovoroda <chalkerx@gmail.com>
PR-URL: https://github.com/nodejs/node/pull/61122
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Daniel Lemire <daniel@lemire.me>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Gürgün Dayıoğlu <hey@gurgun.day>
------------------------------ Generated metadata ------------------------------
PR-URL: https://github.com/nodejs/node/pull/61122
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Daniel Lemire <daniel@lemire.me>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Gürgün Dayıoğlu <hey@gurgun.day>
--------------------------------------------------------------------------------
   ℹ  This PR was created on Fri, 19 Dec 2025 09:36:22 GMT
   ✔  Approvals: 4
   ✔  - Colin Ihrig (@cjihrig): https://github.com/nodejs/node/pull/61122#pullrequestreview-3599469348
   ✔  - Daniel Lemire (@lemire): https://github.com/nodejs/node/pull/61122#pullrequestreview-3600703637
   ✔  - Rafael Gonzaga (@RafaelGSS) (TSC): https://github.com/nodejs/node/pull/61122#pullrequestreview-3674328458
   ✔  - Gürgün Dayıoğlu (@gurgunday): https://github.com/nodejs/node/pull/61122#pullrequestreview-3708188048
   ✘  Last GitHub CI failed
   ℹ  Last Full PR CI on 2026-02-11T03:43:31Z: https://ci.nodejs.org/job/node-test-pull-request/71303/
- Querying data for job/node-test-pull-request/71303/
✔  Build data downloaded
   ✔  Last Jenkins CI successful
--------------------------------------------------------------------------------
   ✔  Aborted `git node land` session in /home/runner/work/node/node/.ncu

https://github.com/nodejs/node/actions/runs/21898227534

mertcanaltin

LGTM

targos · 2026-02-11T08:54:11Z

GitHub CI can't be restarted. I think it's too old.

It has better performance

nodejs-github-bot · 2026-02-11T13:26:44Z

CI: https://ci.nodejs.org/job/node-test-pull-request/71307/

nodejs-github-bot added buffer Issues and PRs related to the buffer subsystem. c++ Issues and PRs that require attention from people who are familiar with C++. needs-ci PRs that need a full CI run. labels Dec 19, 2025

ChALkeR marked this pull request as ready for review December 19, 2025 09:50

ChALkeR changed the title ~~src: use validate_ascii_with_errors instead of validate_asci~~ src: use validate_ascii_with_errors instead of validate_ascii Dec 19, 2025

ChALkeR force-pushed the chalker/ascii/is/0 branch from 1f3f083 to e78cdd1 Compare December 19, 2025 09:53

ChALkeR changed the title ~~src: use validate_ascii_with_errors instead of validate_ascii~~ src: use validate_ascii_with_errors for buffer.isAscii Dec 19, 2025

cjihrig approved these changes Dec 19, 2025

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lemire approved these changes Dec 20, 2025

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lemire mentioned this pull request Dec 20, 2025

Improving the performance of validate_ascii simdutf/simdutf#879

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src: use validate_ascii_with_errors instead of validate_ascii

f11c0ab

It has better performance

ChALkeR force-pushed the chalker/ascii/is/0 branch from e78cdd1 to f11c0ab Compare February 11, 2026 13:14

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