Turbopack: selective read for module_chunk_groups in ChunkGroupInfo #88559

sokra · 2026-01-14T20:08:52Z

What?

Use selective reads for module chunk groups from chunk group info

This is a preparation to make chunking be less dependent on module graph changes.

sokra · 2026-01-14T20:09:09Z

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nextjs-bot · 2026-01-14T20:09:16Z

Allow CI Workflow Run

approve CI run for commit: 123468b

Note: this should only be enabled once the PR is ready to go and can only be enabled by a maintainer

turbopack/crates/turbopack-core/src/chunk/chunking/production.rs

turbopack/crates/turbopack-core/src/module_graph/module_batches.rs

nextjs-bot · 2026-01-14T20:36:04Z

Stats from current PR

✅ No significant changes detected

📊 All Metrics

📖 Metrics Glossary

Dev Server Metrics:

Listen = TCP port starts accepting connections
First Request = HTTP server returns successful response
Cold = Fresh build (no cache)
Warm = With cached build artifacts

Build Metrics:

Fresh = Clean build (no .next directory)
Cached = With existing .next directory

Change Thresholds:

Time: Changes < 50ms AND < 10%, OR < 2% are insignificant
Size: Changes < 1KB AND < 1% are insignificant
All other changes are flagged to catch regressions

⚡ Dev Server

Metric	Canary	PR	Change	Trend
Cold (Listen)	455ms	456ms	✓	▁▁▁▁█
Cold (Ready in log)	436ms	436ms	✓	▂▁▂▂█
Cold (First Request)	1.196s	1.110s	✓	▄▂▄▄█
Warm (Listen)	456ms	457ms	✓	▁▁▁▁█
Warm (Ready in log)	445ms	442ms	✓	▁▁▁▁█
Warm (First Request)	337ms	335ms	✓	▁▂▁▁█

📦 Dev Server (Webpack) (Legacy)

📦 Dev Server (Webpack)

Metric	Canary	PR	Change	Trend
Cold (Listen)	455ms	456ms	✓	▁▁▁▁▁
Cold (Ready in log)	439ms	439ms	✓	▁▁▇▆▁
Cold (First Request)	1.841s	1.810s	✓	▁▁▅▅▂
Warm (Listen)	456ms	455ms	✓	▁▁▁▁▁
Warm (Ready in log)	439ms	439ms	✓	▁▁▅▅▁
Warm (First Request)	1.833s	1.830s	✓	▁▁▅▅▁

⚡ Production Builds

Metric	Canary	PR	Change	Trend
Fresh Build	4.319s	4.308s	✓	▁▃▁▁█
Cached Build	4.274s	4.346s	✓	▁▃▁▁█

📦 Production Builds (Webpack) (Legacy)

📦 Production Builds (Webpack)

Metric	Canary	PR	Change	Trend
Fresh Build	14.009s	14.050s	✓	▁▁▃▃▄
Cached Build	14.115s	14.122s	✓	▂▁▃▃▃
node_modules Size	458 MB	458 MB	✓	▁▁▁▁▁

📦 Bundle Sizes

Bundle Sizes

⚡ Turbopack

Client

Main Bundles: **430 kB** → **430 kB** ✅ -81 B

82 files with content-based hashes (individual files not comparable between builds)

Server

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	790 B	785 B	✓
Total	790 B	785 B	✅ -5 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	449 B	450 B	✓
Total	449 B	450 B	⚠️ +1 B

📦 Webpack

Client

Main Bundles

	Canary	PR	Change
2086.HASH.js gzip	169 B	N/A	-
2161-HASH.js gzip	5.41 kB	N/A	-
2747-HASH.js gzip	4.48 kB	N/A	-
4322-HASH.js gzip	52.3 kB	N/A	-
ec793fe8-HASH.js gzip	62.3 kB	N/A	-
framework-HASH.js gzip	59.8 kB	59.8 kB	✓
main-app-HASH.js gzip	251 B	253 B	✓
main-HASH.js gzip	38.6 kB	38.9 kB	✓
webpack-HASH.js gzip	1.68 kB	1.68 kB	✓
1596.HASH.js gzip	N/A	169 B	-
2658-HASH.js gzip	N/A	51.9 kB	-
6349-HASH.js gzip	N/A	4.46 kB	-
7019-HASH.js gzip	N/A	5.43 kB	-
b17a3386-HASH.js gzip	N/A	62.3 kB	-
Total	225 kB	225 kB	✅ -11 B

Polyfills

	Canary	PR	Change
polyfills-HASH.js gzip	39.4 kB	39.4 kB	✓
Total	39.4 kB	39.4 kB	✓

Pages

	Canary	PR	Change
_app-HASH.js gzip	194 B	193 B	✓
_error-HASH.js gzip	182 B	182 B	✓
css-HASH.js gzip	336 B	335 B	✓
dynamic-HASH.js gzip	1.8 kB	1.8 kB	✓
edge-ssr-HASH.js gzip	256 B	256 B	✓
head-HASH.js gzip	352 B	349 B	✓
hooks-HASH.js gzip	385 B	384 B	✓
image-HASH.js gzip	580 B	580 B	✓
index-HASH.js gzip	259 B	258 B	✓
link-HASH.js gzip	2.5 kB	2.51 kB	✓
routerDirect..HASH.js gzip	319 B	317 B	✓
script-HASH.js gzip	385 B	387 B	✓
withRouter-HASH.js gzip	316 B	315 B	✓
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Total	7.97 kB	7.96 kB	✅ -8 B

Server

Edge SSR

	Canary	PR	Change
edge-ssr.js gzip	125 kB	125 kB	✓
page.js gzip	242 kB	237 kB	🟢 4.87 kB (-2%)
Total	366 kB	362 kB	✅ -4.85 kB

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	654 B	655 B	✓
middleware-r..fest.js gzip	155 B	156 B	✓
middleware.js gzip	32.9 kB	33.3 kB	🔴 +349 B (+1%)
edge-runtime..pack.js gzip	842 B	842 B	✓
Total	34.6 kB	34.9 kB	⚠️ +351 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	738 B	738 B	✓
Total	738 B	738 B	✓

Build Cache

	Canary	PR	Change
0.pack gzip	3.66 MB	3.67 MB	🔴 +8.13 kB (+0%)
index.pack gzip	98.9 kB	98.9 kB	✓
index.pack.old gzip	98.5 kB	101 kB	🔴 +2.48 kB (+3%)
Total	3.86 MB	3.87 MB	⚠️ +10.6 kB

🔄 Shared (bundler-independent)

Runtimes

	Canary	PR	Change
app-page-exp...dev.js gzip	303 kB	303 kB	✓
app-page-exp..prod.js gzip	158 kB	158 kB	✓
app-page-tur...dev.js gzip	303 kB	303 kB	✓
app-page-tur..prod.js gzip	158 kB	158 kB	✓
app-page-tur...dev.js gzip	300 kB	300 kB	✓
app-page-tur..prod.js gzip	156 kB	156 kB	✓
app-page.run...dev.js gzip	300 kB	300 kB	✓
app-page.run..prod.js gzip	156 kB	156 kB	✓
app-route-ex...dev.js gzip	68.8 kB	68.8 kB	✓
app-route-ex..prod.js gzip	47.6 kB	47.6 kB	✓
app-route-tu...dev.js gzip	68.8 kB	68.8 kB	✓
app-route-tu..prod.js gzip	47.6 kB	47.6 kB	✓
app-route-tu...dev.js gzip	68.4 kB	68.4 kB	✓
app-route-tu..prod.js gzip	47.4 kB	47.4 kB	✓
app-route.ru...dev.js gzip	68.4 kB	68.4 kB	✓
app-route.ru..prod.js gzip	47.3 kB	47.3 kB	✓
dist_client_...dev.js gzip	324 B	324 B	✓
dist_client_...dev.js gzip	326 B	326 B	✓
dist_client_...dev.js gzip	318 B	318 B	✓
dist_client_...dev.js gzip	317 B	317 B	✓
pages-api-tu...dev.js gzip	41.2 kB	41.2 kB	✓
pages-api-tu..prod.js gzip	31.3 kB	31.3 kB	✓
pages-api.ru...dev.js gzip	41.1 kB	41.1 kB	✓
pages-api.ru..prod.js gzip	31.2 kB	31.2 kB	✓
pages-turbo....dev.js gzip	50.8 kB	50.8 kB	✓
pages-turbo...prod.js gzip	38.2 kB	38.2 kB	✓
pages.runtim...dev.js gzip	50.7 kB	50.7 kB	✓
pages.runtim..prod.js gzip	38.2 kB	38.2 kB	✓
server.runti..prod.js gzip	62.2 kB	62.2 kB	✓
Total	2.69 MB	2.69 MB	⚠️ +3 B

codspeed-hq · 2026-01-15T11:25:04Z

Merging this PR will not alter performance

✅ 17 untouched benchmarks
⏩ 3 skipped benchmarks¹

_{Comparing sokra/chunk-group-info-selective (866cdb7) with canary (43460b1)}

3 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

nextjs-bot · 2026-01-16T13:36:37Z

Tests Passed

sokra · 2026-01-16T14:33:23Z

Merge activity

Jan 16, 2:33 PM UTC: @sokra merged this pull request with Graphite.

…88559) ### What? Use selective reads for module chunk groups from chunk group info This is a preparation to make chunking be less dependent on module graph changes.

nextjs-bot added created-by: Turbopack team PRs by the Turbopack team. Turbopack Related to Turbopack with Next.js. labels Jan 14, 2026

This was referenced Jan 14, 2026

Turbopack: use selective reads for merged modules #88560

Merged

Turbopack: add caching to chunking #88561

Merged

vercel bot reviewed Jan 14, 2026

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turbopack/crates/turbopack-core/src/chunk/chunking/production.rs Show resolved Hide resolved

turbopack/crates/turbopack-core/src/module_graph/module_batches.rs Show resolved Hide resolved

sokra marked this pull request as ready for review January 15, 2026 07:45

sokra requested a review from mischnic January 15, 2026 07:59

sokra force-pushed the sokra/chunk-group-info-selective branch from 123468b to 57f3026 Compare January 15, 2026 07:59

sokra force-pushed the sokra/selective-read-send branch 2 times, most recently from 77dea0d to ea2c9d1 Compare January 15, 2026 10:51

sokra force-pushed the sokra/chunk-group-info-selective branch from 57f3026 to 7ea2ab2 Compare January 15, 2026 10:51

mischnic approved these changes Jan 15, 2026

View reviewed changes

sokra force-pushed the sokra/selective-read-send branch from ea2c9d1 to f25f974 Compare January 15, 2026 18:37

sokra force-pushed the sokra/chunk-group-info-selective branch from ac32f08 to 4984f09 Compare January 15, 2026 18:37

sokra force-pushed the sokra/selective-read-send branch from f25f974 to 53341fe Compare January 15, 2026 19:22

sokra force-pushed the sokra/chunk-group-info-selective branch from 4984f09 to c7a40b1 Compare January 15, 2026 19:23

sokra force-pushed the sokra/selective-read-send branch 2 times, most recently from 4f4747e to c1533a6 Compare January 16, 2026 05:47

sokra force-pushed the sokra/chunk-group-info-selective branch from c7a40b1 to 7b4c945 Compare January 16, 2026 05:48

sokra force-pushed the sokra/chunk-group-info-selective branch from 7b4c945 to 0b1cd77 Compare January 16, 2026 05:48

sokra changed the base branch from sokra/selective-read-send to graphite-base/88559 January 16, 2026 08:35

sokra force-pushed the sokra/chunk-group-info-selective branch from 0b1cd77 to 6b38c6e Compare January 16, 2026 08:38

sokra force-pushed the graphite-base/88559 branch from c1533a6 to 5f9a8cd Compare January 16, 2026 08:38

sokra changed the base branch from graphite-base/88559 to sokra/selective-read-send January 16, 2026 08:38

sokra force-pushed the sokra/selective-read-send branch from 5f9a8cd to 2f5f742 Compare January 16, 2026 09:02

sokra force-pushed the sokra/chunk-group-info-selective branch from 6b38c6e to d870869 Compare January 16, 2026 09:02

sokra force-pushed the sokra/selective-read-send branch from 2f5f742 to 406722e Compare January 16, 2026 09:43

sokra force-pushed the sokra/chunk-group-info-selective branch from d870869 to 0874e3f Compare January 16, 2026 09:44

sokra force-pushed the sokra/selective-read-send branch from 406722e to 96cee4f Compare January 16, 2026 12:08

sokra force-pushed the sokra/chunk-group-info-selective branch from 0874e3f to 3731bb9 Compare January 16, 2026 12:08

sokra changed the base branch from sokra/selective-read-send to graphite-base/88559 January 16, 2026 12:26

sokra force-pushed the sokra/chunk-group-info-selective branch from 3731bb9 to bcb4795 Compare January 16, 2026 12:27

sokra force-pushed the graphite-base/88559 branch from 96cee4f to 87da776 Compare January 16, 2026 12:27

sokra changed the base branch from graphite-base/88559 to sokra/selective-read-send January 16, 2026 12:27

sokra changed the base branch from sokra/selective-read-send to graphite-base/88559 January 16, 2026 13:17

Turbopack: selective read for module_chunk_groups in ChunkGroupInfo

af412ca

sokra force-pushed the sokra/chunk-group-info-selective branch from bcb4795 to a890206 Compare January 16, 2026 13:18

sokra force-pushed the graphite-base/88559 branch from 87da776 to 43460b1 Compare January 16, 2026 13:18

graphite-app bot changed the base branch from graphite-base/88559 to canary January 16, 2026 13:18

fixup

866cdb7

sokra force-pushed the sokra/chunk-group-info-selective branch from a890206 to 866cdb7 Compare January 16, 2026 13:18

sokra merged commit bbf8aec into canary Jan 16, 2026
290 of 292 checks passed

sokra deleted the sokra/chunk-group-info-selective branch January 16, 2026 14:33

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