http: implement slab allocation for HTTP header parsing #61375

mertcanaltin · 2026-01-13T20:01:58Z

fix: // TODO(bnoordhuis) Use slab allocation, O(n) allocs is bad.

before:

http/bench-parser-fragmented.js n=100000 len=8 frags=2: 951,629.0928924936
http/bench-parser-fragmented.js n=100000 len=16 frags=2: 677,295.1203426437
http/bench-parser-fragmented.js n=100000 len=8 frags=4: 759,881.7857984888
http/bench-parser-fragmented.js n=100000 len=16 frags=4: 509,278.74034996366
http/bench-parser-fragmented.js n=100000 len=8 frags=8: 680,706.0381048893
http/bench-parser-fragmented.js n=100000 len=16 frags=8: 466,898.1840452692

after:
52% faster HTTP header parsing

http/bench-parser-fragmented.js n=100000 len=8 frags=2: 1,231,534.676937666
http/bench-parser-fragmented.js n=100000 len=16 frags=2: 890,580.6675901335
http/bench-parser-fragmented.js n=100000 len=8 frags=4: 1,117,723.8010822271
http/bench-parser-fragmented.js n=100000 len=16 frags=4: 789,398.1180369954
http/bench-parser-fragmented.js n=100000 len=8 frags=8: 869,642.0937523921
http/bench-parser-fragmented.js n=100000 len=16 frags=8: 711,293.8345939534

nodejs-github-bot · 2026-01-13T20:02:04Z

Review requested:

@nodejs/http
@nodejs/net

Copilot

Pull request overview

This pull request implements slab allocation for HTTP header parsing to optimize performance by reducing heap allocations. The implementation addresses a TODO comment about O(n) allocations being inefficient and achieves a reported 52% performance improvement in HTTP header parsing benchmarks.

Changes:

Added a 128-byte fixed-size buffer (slab) to each StringPtr instance for caching small strings
Modified Save() and Update() methods to use slab allocation before falling back to heap allocation
Added using_slab_ flag to track slab usage state alongside existing on_heap_ flag

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codecov · 2026-01-13T21:19:02Z

Codecov Report

❌ Patch coverage is 88.70968% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.51%. Comparing base (daeafc0) to head (3d643fe).
⚠️ Report is 188 commits behind head on main.

Files with missing lines	Patch %	Lines
src/node_http_parser.cc	88.70%	1 Missing and 6 partials ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##             main   #61375    +/-   ##
========================================
  Coverage   88.51%   88.51%            
========================================
  Files         704      704            
  Lines      208776   209024   +248     
  Branches    40301    40361    +60     
========================================
+ Hits       184803   185028   +225     
+ Misses      15966    15963     -3     
- Partials     8007     8033    +26

Files with missing lines	Coverage Δ
src/node_http_parser.cc	`84.72% <88.70%> (-0.08%)`	⬇️

... and 74 files with indirect coverage changes

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Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 1 comment.

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src/node_http_parser.cc

addaleax · 2026-01-15T16:42:18Z

src/node_http_parser.cc

+  bool on_heap_ = false;
+  bool using_slab_ = false;
+  size_t size_ = 0;
+  char slab_[kSlabSize];


This overall seems like we're re-inventing MaybeStackBuffer here – I think we could just re-use that?

Thanks! , I've refactored this to use MaybeStackBuffer as the backing store for a allocator.

new benchmark result :

asis (main):

./out/Release/node benchmark/http/bench-parser.js

http/bench-parser.js n=100000 len=4: 1,728,678.1850683796 http/bench-parser.js n=100000 len=8: 1,395,311.5272280464 http/bench-parser.js n=100000 len=16: 981,492.7277523204 http/bench-parser.js n=100000 len=32: 641,907.2347759664

./out/Release/node benchmark/http/bench-parser-fragmented.js

http/bench-parser-fragmented.js n=100000 frags=2 len=8: 1,092,175.0170709684 http/bench-parser-fragmented.js n=100000 frags=4 len=8: 883,046.0674095292 http/bench-parser-fragmented.js n=100000 frags=8 len=8: 772,164.5013385202 http/bench-parser-fragmented.js n=100000 frags=2 len=16: 766,964.5365185371 http/bench-parser-fragmented.js n=100000 frags=4 len=16: 640,379.4448008832 http/bench-parser-fragmented.js n=100000 frags=8 len=16: 520,572.0305757982

new:

./out/Release/node benchmark/http/bench-parser.js

http/bench-parser.js n=100000 len=4: 1,764,556.6527588428 http/bench-parser.js n=100000 len=8: 1,500,760.6980788389 http/bench-parser.js n=100000 len=16: 1,095,013.3922327897 http/bench-parser.js n=100000 len=32: 646,285.1635436564

./out/Release/node benchmark/http/bench-parser-fragmented.js

http/bench-parser-fragmented.js n=100000 frags=2 len=8: 1,361,774.7618279774 http/bench-parser-fragmented.js n=100000 frags=4 len=8: 1,263,148.5873261988 http/bench-parser-fragmented.js n=100000 frags=8 len=8: 1,056,199.0301452405 http/bench-parser-fragmented.js n=100000 frags=2 len=16: 1,021,757.915898309 http/bench-parser-fragmented.js n=100000 frags=4 len=16: 923,235.2934387976 http/bench-parser-fragmented.js n=100000 frags=8 len=16: 826,609.3826364499

src/node_http_parser.cc

mertcanaltin · 2026-01-15T18:09:11Z

uh sorry, I'm forget send benchmark file

nodejs-github-bot · 2026-01-20T17:17:37Z

CI: https://ci.nodejs.org/job/node-test-pull-request/70923/

nodejs-github-bot · 2026-01-20T21:18:30Z

CI: https://ci.nodejs.org/job/node-test-pull-request/70931/

src/node_http_parser.cc

…Update methods

addaleax

Sorry for the delay, I'm currently on PTO – this PR LGTM, thank you for all the effort here! ✨

nodejs-github-bot · 2026-02-04T11:20:24Z

CI: https://ci.nodejs.org/job/node-test-pull-request/71195/

mcollina

lgtm

nodejs-github-bot · 2026-02-04T14:11:03Z

Landed in 5e818c9

PR-URL: #61375 Reviewed-By: Yagiz Nizipli <[email protected]> Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Matteo Collina <[email protected]>

This MR contains the following updates: | Package | Update | Change | |---|---|---| | [node](https://nodejs.org) ([source](https://github.com/nodejs/node)) | patch | `25.6.0` → `25.6.1` | MR created with the help of [el-capitano/tools/renovate-bot](https://gitlab.com/el-capitano/tools/renovate-bot). **Proposed changes to behavior should be submitted there as MRs.** --- ### Release Notes <details> <summary>nodejs/node (node)</summary> ### [`v25.6.1`](https://github.com/nodejs/node/releases/tag/v25.6.1): 2026-02-10, Version 25.6.1 (Current), @aduh95 [Compare Source](nodejs/node@v25.6.0...v25.6.1) ##### Notable Changes - \[[`47df4328d7`](nodejs/node@47df4328d7)] - **build,deps**: replace `cjs-module-lexer` with `merve` (Yagiz Nizipli) [#61456](nodejs/node#61456) ##### Commits - \[[`47df4328d7`](nodejs/node@47df4328d7)] - **build,deps**: replace cjs-module-lexer with merve (Yagiz Nizipli) [#61456](nodejs/node#61456) - \[[`a727054503`](nodejs/node@a727054503)] - **deps**: upgrade npm to 11.9.0 (npm team) [#61685](nodejs/node#61685) - \[[`c78c49ed6b`](nodejs/node@c78c49ed6b)] - **deps**: update amaro to 1.1.7 (Node.js GitHub Bot) [#61730](nodejs/node#61730) - \[[`4790816d9b`](nodejs/node@4790816d9b)] - **deps**: update minimatch to 10.1.2 (Node.js GitHub Bot) [#61732](nodejs/node#61732) - \[[`8c71740e8a`](nodejs/node@8c71740e8a)] - **deps**: update undici to 7.21.0 (Node.js GitHub Bot) [#61683](nodejs/node#61683) - \[[`e559ef6ab1`](nodejs/node@e559ef6ab1)] - **deps**: update googletest to [`56efe39`](nodejs/node@56efe39) (Node.js GitHub Bot) [#61605](nodejs/node#61605) - \[[`300de2bb5a`](nodejs/node@300de2bb5a)] - **deps**: update amaro to 1.1.6 (Node.js GitHub Bot) [#61603](nodejs/node#61603) - \[[`e71e9505ef`](nodejs/node@e71e9505ef)] - **dns**: fix Windows SRV ECONNREFUSED by adjusting c-ares fallback detection (notvivek12) [#61453](nodejs/node#61453) - \[[`439b816bc7`](nodejs/node@439b816bc7)] - **doc**: clarify EventEmitter error handling in threat model (Matteo Collina) [#61701](nodejs/node#61701) - \[[`c1c6641f23`](nodejs/node@c1c6641f23)] - **doc**: mention default option for test runner env (Steven) [#61659](nodejs/node#61659) - \[[`41ec451f98`](nodejs/node@41ec451f98)] - **doc**: fix --inspect security warning section (Tim Perry) [#61675](nodejs/node#61675) - \[[`bb90ef2356`](nodejs/node@bb90ef2356)] - **doc**: document `url.format(urlString)` as deprecated under DEP0169 (René) [#61644](nodejs/node#61644) - \[[`513df82e6f`](nodejs/node@513df82e6f)] - **doc**: update to Visual Studio 2026 manual install (Mike McCready) [#61655](nodejs/node#61655) - \[[`9409d30736`](nodejs/node@9409d30736)] - **doc**: deprecation add more codemod (Augustin Mauroy) [#61642](nodejs/node#61642) - \[[`75a7a67151`](nodejs/node@75a7a67151)] - **doc**: fix grammatical error in README.md (ayj8201) [#61653](nodejs/node#61653) - \[[`821e59e884`](nodejs/node@821e59e884)] - **doc**: correct tools README Boxstarter link (Mike McCready) [#61638](nodejs/node#61638) - \[[`4998f539a0`](nodejs/node@4998f539a0)] - **doc**: update `server.dropMaxConnection` link (YuSheng Chen) [#61584](nodejs/node#61584) - \[[`9383ac4ab7`](nodejs/node@9383ac4ab7)] - **http**: implement slab allocation for HTTP header parsing (Mert Can Altin) [#61375](nodejs/node#61375) - \[[`e90eb1d561`](nodejs/node@e90eb1d561)] - **meta**: persist sccache daemon until end of build workflows (René) [#61639](nodejs/node#61639) - \[[`ade36ac367`](nodejs/node@ade36ac367)] - **meta**: bump github/codeql-action from 4.31.9 to 4.32.0 (dependabot\[bot]) [#61622](nodejs/node#61622) - \[[`26638bd67f`](nodejs/node@26638bd67f)] - **meta**: bump step-security/harden-runner from 2.14.0 to 2.14.1 (dependabot\[bot]) [#61621](nodejs/node#61621) - \[[`eaa9a96cb6`](nodejs/node@eaa9a96cb6)] - **meta**: bump actions/setup-python from 6.1.0 to 6.2.0 (dependabot\[bot]) [#61627](nodejs/node#61627) - \[[`fd98187828`](nodejs/node@fd98187828)] - **meta**: bump cachix/cachix-action (dependabot\[bot]) [#61626](nodejs/node#61626) - \[[`820c1d021c`](nodejs/node@820c1d021c)] - **meta**: bump actions/setup-node from 6.1.0 to 6.2.0 (dependabot\[bot]) [#61625](nodejs/node#61625) - \[[`72a4136bd5`](nodejs/node@72a4136bd5)] - **meta**: bump actions/cache from 5.0.1 to 5.0.3 (dependabot\[bot]) [#61624](nodejs/node#61624) - \[[`e3ef6cb3bc`](nodejs/node@e3ef6cb3bc)] - **meta**: bump peter-evans/create-pull-request from 8.0.0 to 8.1.0 (dependabot\[bot]) [#61623](nodejs/node#61623) - \[[`020a836202`](nodejs/node@020a836202)] - **meta**: bump actions/stale from 10.1.0 to 10.1.1 (dependabot\[bot]) [#61620](nodejs/node#61620) - \[[`0df72f07c8`](nodejs/node@0df72f07c8)] - **meta**: bump actions/checkout from 6.0.1 to 6.0.2 (dependabot\[bot]) [#61619](nodejs/node#61619) - \[[`d147c08b83`](nodejs/node@d147c08b83)] - **module**: do not invoke resolve hooks twice for imported cjs (Joyee Cheung) [#61529](nodejs/node#61529) - \[[`a2843f8556`](nodejs/node@a2843f8556)] - **net**: defer synchronous destroy calls in internalConnect (RajeshKumar11) [#61658](nodejs/node#61658) - \[[`7fb7030781`](nodejs/node@7fb7030781)] - **repl**: fix flaky test-repl-programmatic-history (Matteo Collina) [#61614](nodejs/node#61614) - \[[`d4c9b5cf5b`](nodejs/node@d4c9b5cf5b)] - **sqlite**: avoid extra copy for large text binds (Ali Hassan) [#61580](nodejs/node#61580) - \[[`aa1b3661d9`](nodejs/node@aa1b3661d9)] - **sqlite**: use DictionaryTemplate for run() result (Mert Can Altin) [#61432](nodejs/node#61432) - \[[`9c8ad7e881`](nodejs/node@9c8ad7e881)] - **src**: elide heap allocation in structured clone implementation (Anna Henningsen) [#61703](nodejs/node#61703) - \[[`c4ecfef93d`](nodejs/node@c4ecfef93d)] - **src**: use simdutf for one-byte string UTF-8 write in stringBytes (Mert Can Altin) [#61696](nodejs/node#61696) - \[[`28905b9734`](nodejs/node@28905b9734)] - **src**: consolidate C++ ReadFileSync/WriteFileSync utilities (Joyee Cheung) [#61662](nodejs/node#61662) - \[[`e90cec2f69`](nodejs/node@e90cec2f69)] - **test**: restraint version replacement pattern in snapshots (Chengzhong Wu) [#61748](nodejs/node#61748) - \[[`adce20c0a1`](nodejs/node@adce20c0a1)] - 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**test**: unify assertSnapshot common patterns (Chengzhong Wu) [#61590](nodejs/node#61590) - \[[`17122e521b`](nodejs/node@17122e521b)] - **test\_runner**: fix test enqueue when test file has syntax error (Edy Silva) [#61573](nodejs/node#61573) - \[[`bad3f02dd9`](nodejs/node@bad3f02dd9)] - **tools**: enforce removal of `lts-watch-*` labels on release proposals (Antoine du Hamel) [#61672](nodejs/node#61672) - \[[`a8f33fd6bd`](nodejs/node@a8f33fd6bd)] - **tools**: use ubuntu-slim runner in meta GitHub Actions (Tierney Cyren) [#61663](nodejs/node#61663) - \[[`c843e447ca`](nodejs/node@c843e447ca)] - **tools**: test `--shared-merve` in `test-shared` workflow (Antoine du Hamel) [#61649](nodejs/node#61649) - \[[`2fedc03f96`](nodejs/node@2fedc03f96)] - **tools**: update OpenSSL to 3.5.5 in `test-shared` (Antoine du Hamel) [#61551](nodejs/node#61551) - \[[`1c1db94670`](nodejs/node@1c1db94670)] - **tools,win**: upgrade install additional tools to Visual Studio 2026 (Mike McCready) [#61562](nodejs/node#61562) </details> --- ### Configuration 📅 **Schedule**: Branch creation - 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http: implement slab allocation for HTTP header parsing

20bde47

nodejs-github-bot added c++ Issues and PRs that require attention from people who are familiar with C++. http_parser Issues and PRs related to the HTTP Parser dependency or the http_parser binding. needs-ci PRs that need a full CI run. labels Jan 13, 2026

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mertcanaltin added 2 commits January 15, 2026 21:13

benchmark: add fragmented HTTP header parsing benchmark

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implement shared slab allocation

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mertcanaltin added 3 commits January 21, 2026 20:26

rename Allocate call

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optimize StringPtrAllocator memory management

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refactor StringPtr and Parser to use allocator parameter in Save and …

3d643fe

…Update methods

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aduh95 pushed a commit that referenced this pull request Feb 8, 2026

http: implement slab allocation for HTTP header parsing

9383ac4

PR-URL: #61375 Reviewed-By: Yagiz Nizipli <[email protected]> Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Matteo Collina <[email protected]>

github-actions bot mentioned this pull request Feb 8, 2026

2026-02-10, Version 25.6.1 (Current) #61739

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aduh95 pushed a commit that referenced this pull request Feb 10, 2026

http: implement slab allocation for HTTP header parsing

76b0af1

PR-URL: #61375 Reviewed-By: Yagiz Nizipli <[email protected]> Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Matteo Collina <[email protected]>

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http: implement slab allocation for HTTP header parsing #61375

http: implement slab allocation for HTTP header parsing #61375

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