fix(timing): more self-contained timing/log data #16378

weihanglo · 2025-12-11T15:17:36Z

What does this PR try to resolve?

Factored out of #16377.
This makes data more self-contained.

How to test and review this PR?

rustbot · 2025-12-11T15:17:42Z

rustbot has assigned @ehuss.
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epage · 2025-12-11T15:33:07Z

src/cargo/core/compiler/timings/report.rs

-    let num_cpus = std::thread::available_parallelism()
-        .map(|x| x.get().to_string())
-        .unwrap_or_else(|_| "n/a".into());


Huh, surprised we don't take the config overriding this into account

weihanglo · 2025-12-11T15:58:19Z

#16380 needs to be merged first to fix the CI failure.

This is more accurate than running time elapsed again.

Otherwise HTML replay from logs will not have this info

rustbot · 2025-12-11T18:21:51Z

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

### What does this PR try to resolve? This implements `cargo report timings` HTML replay feature. The help text looks like: ``` Reports the build timings of previous builds (unstable) Usage: cargo report timings [OPTIONS] Options: --open Opens the timing report in a browser ... ``` Part of <#15844> ### How to test and review this PR? Open questions: * [ ] The replayed HTML report will be written to * If in a Cargo workspace, write to `<artifact-dir>/cargo-timings/` * Otherwise, write to a temp directory * [ ] The log discovery logic * Currently look at the newest log file for the workspace. * If not in a workspace, pick the newest log file in the log directory. * [ ] Snapshots HTML report and log files are added. * They are huge in size. Should we not do this? * Benefit: HTML snapshots help us know better when it is broken ### Things left (but should do it follow-up PRs) * [ ] `cargo help` hasn't yet worked with with nested commands. * [ ] There are some more information required by HTML report, but these don't affect the major use of the report IMO. * [ ] fresh/dirty/total units * [ ] information of root units * [ ] enabled features for each unit * [ ] `--target` platform * [ ] CPU usage metrics * [x] number of available parallelism #16378

Update cargo submodule 27 commits in 2c283a9a5c5968eeb9a8f12313f04feb1ff8dfac..c46423de7351e3c4c734b2faa86088a9f5d1302b 2025-12-04 16:47:28 +0000 to 2025-12-12 23:16:12 +0000 - feat(report): cargo report timings HTML replay (rust-lang/cargo#16377) - feat: stabilize `-Zconfig-include` (rust-lang/cargo#16284) - fix(package): Don't verify registry for --list (rust-lang/cargo#16341) - Fixed incorrect locking logic when artifact-dir == build-dir (rust-lang/cargo#16385) - feat(log): make timing messages ready for HTML replay (rust-lang/cargo#16382) - chore(deps): update msrv (1 version) to v1.92 (rust-lang/cargo#16381) - Downgrade curl-sys to 0.4.83 (rust-lang/cargo#16379) - fix(timing): more self-contained timing/log data (rust-lang/cargo#16378) - test: update to `proc_macro::tracked::path` (rust-lang/cargo#16380) - refactor(lint): move lints to separate modules (rust-lang/cargo#16364) - fix(index): Apply feedback from Cargo team (rust-lang/cargo#16369) - fix(lints): handle lints separately at ws pkg level (rust-lang/cargo#16367) - feat(lint): new `implicit_minimum_version_req` lint (rust-lang/cargo#16321) - fix(info): default to local without explicit reg (rust-lang/cargo#16358) - Remove `[no-mentions]` handler in our triagebot config (rust-lang/cargo#16361) - Don't read the config file twice when $CARGO_HOME is a symlink (rust-lang/cargo#16325) - fix(timings): forgot to negate filter (rust-lang/cargo#16352) - fix(doctest): Include all search paths with new build layout (rust-lang/cargo#16348) - fix(layout): Remove hashes from bins in new layout (rust-lang/cargo#16351) - docs(faq): Include an entry on disk space (rust-lang/cargo#16349) - feat(timings): derive concurrency data from unit data (rust-lang/cargo#16350) - perf(layout): Use unit_id, not pkg hash, for bin/lib pkg_dirs for new layout (rust-lang/cargo#16345) - Validate target source paths before compilation with clearer errors (rust-lang/cargo#16338) - test(doc): Remove unused build script (rust-lang/cargo#16344) - refactor(timings): store UnitData in RenderContext instead (rust-lang/cargo#16346) - perf(clean): Optimize (legacy) clean with multiple -p specifiers (rust-lang/cargo#16264) - test: Adjust output for out-of-tree build-dir (rust-lang/cargo#16343)

Update cargo submodule 29 commits in 2c283a9a5c5968eeb9a8f12313f04feb1ff8dfac..e91b2baa632c0c7e84216c91ecfe107c37d887c1 2025-12-04 16:47:28 +0000 to 2025-12-13 16:29:21 +0000 - refactor(lints): move from cargo::util::lints to cargo::lints (rust-lang/cargo#16392) - test(lint): redact more due to line got omitted (rust-lang/cargo#16391) - feat(report): cargo report timings HTML replay (rust-lang/cargo#16377) - feat: stabilize `-Zconfig-include` (rust-lang/cargo#16284) - fix(package): Don't verify registry for --list (rust-lang/cargo#16341) - Fixed incorrect locking logic when artifact-dir == build-dir (rust-lang/cargo#16385) - feat(log): make timing messages ready for HTML replay (rust-lang/cargo#16382) - chore(deps): update msrv (1 version) to v1.92 (rust-lang/cargo#16381) - Downgrade curl-sys to 0.4.83 (rust-lang/cargo#16379) - fix(timing): more self-contained timing/log data (rust-lang/cargo#16378) - test: update to `proc_macro::tracked::path` (rust-lang/cargo#16380) - refactor(lint): move lints to separate modules (rust-lang/cargo#16364) - fix(index): Apply feedback from Cargo team (rust-lang/cargo#16369) - fix(lints): handle lints separately at ws pkg level (rust-lang/cargo#16367) - feat(lint): new `implicit_minimum_version_req` lint (rust-lang/cargo#16321) - fix(info): default to local without explicit reg (rust-lang/cargo#16358) - Remove `[no-mentions]` handler in our triagebot config (rust-lang/cargo#16361) - Don't read the config file twice when $CARGO_HOME is a symlink (rust-lang/cargo#16325) - fix(timings): forgot to negate filter (rust-lang/cargo#16352) - fix(doctest): Include all search paths with new build layout (rust-lang/cargo#16348) - fix(layout): Remove hashes from bins in new layout (rust-lang/cargo#16351) - docs(faq): Include an entry on disk space (rust-lang/cargo#16349) - feat(timings): derive concurrency data from unit data (rust-lang/cargo#16350) - perf(layout): Use unit_id, not pkg hash, for bin/lib pkg_dirs for new layout (rust-lang/cargo#16345) - Validate target source paths before compilation with clearer errors (rust-lang/cargo#16338) - test(doc): Remove unused build script (rust-lang/cargo#16344) - refactor(timings): store UnitData in RenderContext instead (rust-lang/cargo#16346) - perf(clean): Optimize (legacy) clean with multiple -p specifiers (rust-lang/cargo#16264) - test: Adjust output for out-of-tree build-dir (rust-lang/cargo#16343)

rustbot assigned ehuss Dec 11, 2025

rustbot added A-timings Area: timings S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Dec 11, 2025

weihanglo force-pushed the timing branch from aefe03a to 660919a Compare December 11, 2025 15:24

weihanglo mentioned this pull request Dec 11, 2025

feat(report): cargo report timings HTML replay #16377

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11 tasks

epage reviewed Dec 11, 2025

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epage approved these changes Dec 11, 2025

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weihanglo added 3 commits December 11, 2025 13:09

fix(timing): dont panic when unit_data is empty

19cd61e

fix(timing): derive total build time from last concurrency data

2a47166

This is more accurate than running time elapsed again.

feat(log): log available parallelism

9627f4d

Otherwise HTML replay from logs will not have this info

weihanglo force-pushed the timing branch from 660919a to 9627f4d Compare December 11, 2025 18:21

weihanglo enabled auto-merge December 11, 2025 18:44

weihanglo added this pull request to the merge queue Dec 11, 2025

Merged via the queue into rust-lang:master with commit 608fd7e Dec 11, 2025
27 of 28 checks passed

weihanglo deleted the timing branch December 11, 2025 19:26

rustbot removed the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Dec 11, 2025

This was referenced Dec 12, 2025

Tracking Issue for -Zbuild-analysis #15844

Open

Update cargo submodule rust-lang/rust#149934

Merged

weihanglo mentioned this pull request Dec 13, 2025

Prototype Cargo build analysis rust-lang/rust-project-goals#398

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rustbot added this to the 1.94.0 milestone Dec 13, 2025

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fix(timing): more self-contained timing/log data #16378

fix(timing): more self-contained timing/log data #16378

weihanglo commented Dec 11, 2025

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fix(timing): more self-contained timing/log data #16378

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weihanglo commented Dec 11, 2025

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