test(trace-utils): add VecMap microbenchmarks by yannham · Pull Request #2126 · DataDog/libdatadog

yannham · 2026-06-16T09:00:09Z

What does this PR do?

Adds criterion microbenchmarks for VecMap (libdd-trace-utils/src/span/vec_map.rs), the linear-scan ordered map backing each span's meta and metrics. The benches isolate the datastructure's core operations across representative map sizes (4, 8, 16, 32, 64), using BytesString keys to match real span usage:

insert (construction path), get (hit and miss), get_mut, contains_key
iter (encode path)
dedup (runs once per span on decode), with and without duplicate keys
as_deduped_map (encode path), both the cheap borrow case and the allocating fallback

A new opt-in bench-internals feature (mirroring libdd-sampling) gates the bench via required-features so it is not built by default. The change is additive to Cargo.toml.

Motivation

VecMap is a swappable datastructure (could be a hashmap/btree) that runs on the tracer hot path, but existing trace-utils benches only measure end-to-end msgpack encode/decode and never isolate it. Since it is linear-scan, the size-vs-operation curve is exactly what should be measured so the backing-structure choice can be revisited with data.

Additional Notes

VecMap and the span module are already pub, so bench-internals does not gate any source visibility; it is purely an opt-in switch keeping the bench out of the default build, consistent with libdd-sampling. Data is fully deterministic (no randomness).

How to test the change?

cargo bench -p libdd-trace-utils --features bench-internals --bench vec_map_bench --no-run
cargo bench -p libdd-trace-utils --features bench-internals --bench vec_map_bench

🤖 Generated with Claude Code

github-actions · 2026-06-16T09:01:56Z

📚 Documentation Check Results

⚠️ 676 documentation warning(s) found

📦 `libdd-trace-utils` - 676 warning(s)

Updated: 2026-06-17 14:00:16 UTC | Commit: 9176448 | missing-docs job results

github-actions · 2026-06-16T09:03:59Z

Clippy Allow Annotation Report

Comparing clippy allow annotations between branches:

Base Branch: origin/main
PR Branch: origin/yannham/microbenches-vecmap

Summary by Rule

Rule	Base Branch	PR Branch	Change

Annotation Counts by File

File	Base Branch	PR Branch	Change

Annotation Stats by Crate

Crate	Base Branch	PR Branch	Change
`clippy-annotation-reporter`	5	5	No change (0%)
`datadog-ffe-ffi`	1	1	No change (0%)
`datadog-ipc`	21	21	No change (0%)
`datadog-live-debugger`	4	4	No change (0%)
`datadog-live-debugger-ffi`	10	10	No change (0%)
`datadog-profiling-replayer`	4	4	No change (0%)
`datadog-sidecar`	46	46	No change (0%)
`libdd-common`	13	13	No change (0%)
`libdd-common-ffi`	12	12	No change (0%)
`libdd-data-pipeline`	5	5	No change (0%)
`libdd-ddsketch`	2	2	No change (0%)
`libdd-dogstatsd-client`	1	1	No change (0%)
`libdd-profiling`	13	13	No change (0%)
`libdd-remote-config`	3	3	No change (0%)
`libdd-telemetry`	20	20	No change (0%)
`libdd-tinybytes`	4	4	No change (0%)
`libdd-trace-normalization`	2	2	No change (0%)
`libdd-trace-obfuscation`	3	3	No change (0%)
`libdd-trace-stats`	1	1	No change (0%)
`libdd-trace-utils`	12	12	No change (0%)
Total	182	182	No change (0%)

About This Report

This report tracks Clippy allow annotations for specific rules, showing how they've changed in this PR. Decreasing the number of these annotations generally improves code quality.

github-actions · 2026-06-16T09:03:59Z

🔒 Cargo Deny Results

⚠️ 4 issue(s) found, showing only errors (advisories, bans, sources)

📦 `libdd-trace-utils` - 4 error(s)

Show output

error[unsound]: Rand is unsound with a custom logger using `rand::rng()`
    ┌─ /home/runner/work/libdatadog/libdatadog/Cargo.lock:177:1
    │
177 │ rand 0.8.5 registry+https://github.com/rust-lang/crates.io-index
    │ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ unsound advisory detected
    │
    ├ ID: RUSTSEC-2026-0097
    ├ Advisory: https://rustsec.org/advisories/RUSTSEC-2026-0097
    ├ It has been reported (by @lopopolo) that the `rand` library is [unsound](https://rust-lang.github.io/unsafe-code-guidelines/glossary.html#soundness-of-code--of-a-library) (i.e. that safe code using the public API can cause Undefined Behaviour) when all the following conditions are met:
      
      - The `log` and `thread_rng` features are enabled
      - A [custom logger](https://docs.rs/log/latest/log/#implementing-a-logger) is defined
      - The custom logger accesses `rand::rng()` (previously `rand::thread_rng()`) and calls any `TryRng` (previously `RngCore`) methods on `ThreadRng`
      - The `ThreadRng` (attempts to) reseed while called from the custom logger (this happens every 64 kB of generated data)
      - Trace-level logging is enabled or warn-level logging is enabled and the random source (the `getrandom` crate) is unable to provide a new seed
      
      `TryRng` (previously `RngCore`) methods for `ThreadRng` use `unsafe` code to cast `*mut BlockRng<ReseedingCore>` to `&mut BlockRng<ReseedingCore>`. When all the above conditions are met this results in an aliased mutable reference, violating the Stacked Borrows rules. Miri is able to detect this violation in sample code. Since construction of [aliased mutable references is Undefined Behaviour](https://doc.rust-lang.org/stable/nomicon/references.html), the behaviour of optimized builds is hard to predict.
    ├ Announcement: https://github.com/rust-random/rand/pull/1763
    ├ Solution: Upgrade to >=0.10.1 OR <0.10.0, >=0.9.3 OR <0.9.0, >=0.8.6 (try `cargo update -p rand`)
    ├ rand v0.8.5
      ├── (dev) libdd-common v4.2.0
      │   ├── libdd-capabilities-impl v2.0.0
      │   │   └── libdd-trace-utils v8.0.0
      │   │       └── (dev) libdd-trace-utils v8.0.0 (*)
      │   └── libdd-trace-utils v8.0.0 (*)
      ├── (dev) libdd-trace-normalization v2.0.0
      │   └── libdd-trace-utils v8.0.0 (*)
      ├── libdd-trace-utils v8.0.0 (*)
      └── proptest v1.5.0
          └── (dev) libdd-tinybytes v1.1.1
              ├── (dev) libdd-tinybytes v1.1.1 (*)
              └── libdd-trace-utils v8.0.0 (*)

error[vulnerability]: Name constraints for URI names were incorrectly accepted
    ┌─ /home/runner/work/libdatadog/libdatadog/Cargo.lock:199:1
    │
199 │ rustls-webpki 0.103.10 registry+https://github.com/rust-lang/crates.io-index
    │ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ security vulnerability detected
    │
    ├ ID: RUSTSEC-2026-0098
    ├ Advisory: https://rustsec.org/advisories/RUSTSEC-2026-0098
    ├ Name constraints for URI names were ignored and therefore accepted.
      
      Note this library does not provide an API for asserting URI names, and URI name constraints are otherwise not implemented.  URI name constraints are now rejected unconditionally.
      
      Since name constraints are restrictions on otherwise properly-issued certificates, this bug is reachable only after signature verification and requires misissuance to exploit.
      
      This vulnerability is identified as [GHSA-965h-392x-2mh5](https://github.com/rustls/webpki/security/advisories/GHSA-965h-392x-2mh5). Thank you to @1seal for the report.
    ├ Solution: Upgrade to >=0.103.12, <0.104.0-alpha.1 OR >=0.104.0-alpha.6 (try `cargo update -p rustls-webpki`)
    ├ rustls-webpki v0.103.10
      └── rustls v0.23.37
          ├── hyper-rustls v0.27.7
          │   └── libdd-common v4.2.0
          │       ├── libdd-capabilities-impl v2.0.0
          │       │   └── libdd-trace-utils v8.0.0
          │       │       └── (dev) libdd-trace-utils v8.0.0 (*)
          │       └── libdd-trace-utils v8.0.0 (*)
          ├── libdd-common v4.2.0 (*)
          └── tokio-rustls v0.26.0
              ├── hyper-rustls v0.27.7 (*)
              └── libdd-common v4.2.0 (*)

error[vulnerability]: Name constraints were accepted for certificates asserting a wildcard name
    ┌─ /home/runner/work/libdatadog/libdatadog/Cargo.lock:199:1
    │
199 │ rustls-webpki 0.103.10 registry+https://github.com/rust-lang/crates.io-index
    │ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ security vulnerability detected
    │
    ├ ID: RUSTSEC-2026-0099
    ├ Advisory: https://rustsec.org/advisories/RUSTSEC-2026-0099
    ├ Permitted subtree name constraints for DNS names were accepted for certificates asserting a wildcard name.
      
      This was incorrect because, given a name constraint of `accept.example.com`, `*.example.com` could feasibly allow a name of `reject.example.com` which is outside the constraint.
      This is very similar to [CVE-2025-61727](https://go.dev/issue/76442).
      
      Since name constraints are restrictions on otherwise properly-issued certificates, this bug is reachable only after signature verification and requires misissuance to exploit.
      
      This vulnerability is identified as [GHSA-xgp8-3hg3-c2mh](https://github.com/rustls/webpki/security/advisories/GHSA-xgp8-3hg3-c2mh). Thank you to @1seal for the report.
    ├ Solution: Upgrade to >=0.103.12, <0.104.0-alpha.1 OR >=0.104.0-alpha.6 (try `cargo update -p rustls-webpki`)
    ├ rustls-webpki v0.103.10
      └── rustls v0.23.37
          ├── hyper-rustls v0.27.7
          │   └── libdd-common v4.2.0
          │       ├── libdd-capabilities-impl v2.0.0
          │       │   └── libdd-trace-utils v8.0.0
          │       │       └── (dev) libdd-trace-utils v8.0.0 (*)
          │       └── libdd-trace-utils v8.0.0 (*)
          ├── libdd-common v4.2.0 (*)
          └── tokio-rustls v0.26.0
              ├── hyper-rustls v0.27.7 (*)
              └── libdd-common v4.2.0 (*)

error[vulnerability]: Reachable panic in certificate revocation list parsing
    ┌─ /home/runner/work/libdatadog/libdatadog/Cargo.lock:199:1
    │
199 │ rustls-webpki 0.103.10 registry+https://github.com/rust-lang/crates.io-index
    │ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ security vulnerability detected
    │
    ├ ID: RUSTSEC-2026-0104
    ├ Advisory: https://rustsec.org/advisories/RUSTSEC-2026-0104
    ├ A panic was reachable when parsing certificate revocation lists via [`BorrowedCertRevocationList::from_der`]
      or [`OwnedCertRevocationList::from_der`].  This was the result of mishandling a syntactically valid empty
      `BIT STRING` appearing in the `onlySomeReasons` element of a `IssuingDistributionPoint` CRL extension.
      
      This panic is reachable prior to a CRL's signature being verified.
      
      Applications that do not use CRLs are not affected.
      
      Thank you to @tynus3 for the report.
    ├ Solution: Upgrade to >=0.103.13, <0.104.0-alpha.1 OR >=0.104.0-alpha.7 (try `cargo update -p rustls-webpki`)
    ├ rustls-webpki v0.103.10
      └── rustls v0.23.37
          ├── hyper-rustls v0.27.7
          │   └── libdd-common v4.2.0
          │       ├── libdd-capabilities-impl v2.0.0
          │       │   └── libdd-trace-utils v8.0.0
          │       │       └── (dev) libdd-trace-utils v8.0.0 (*)
          │       └── libdd-trace-utils v8.0.0 (*)
          ├── libdd-common v4.2.0 (*)
          └── tokio-rustls v0.26.0
              ├── hyper-rustls v0.27.7 (*)
              └── libdd-common v4.2.0 (*)

advisories FAILED, bans ok, sources ok

Updated: 2026-06-17 14:00:22 UTC | Commit: 9176448 | dependency-check job results

datadog-datadog-prod-us1 · 2026-06-16T09:13:36Z

Tests

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 73.33% (-0.04%)

_{This comment will be updated automatically if new data arrives.

🔗 Commit SHA: 041db43 | Docs | Datadog PR Page | Give us feedback!}

dd-octo-sts · 2026-06-16T09:34:58Z

Artifact Size Benchmark Report

aarch64-alpine-linux-musl

Artifact	Baseline	Commit	Change
/aarch64-alpine-linux-musl/lib/libdatadog_profiling.a	84.02 MB	84.02 MB	0% (0 B) 👌
/aarch64-alpine-linux-musl/lib/libdatadog_profiling.so	7.76 MB	7.76 MB	0% (0 B) 👌

aarch64-unknown-linux-gnu

Artifact	Baseline	Commit	Change
/aarch64-unknown-linux-gnu/lib/libdatadog_profiling.so	10.36 MB	10.36 MB	0% (0 B) 👌
/aarch64-unknown-linux-gnu/lib/libdatadog_profiling.a	95.13 MB	95.13 MB	0% (0 B) 👌

libdatadog-x64-windows

Artifact	Baseline	Commit	Change
/libdatadog-x64-windows/debug/dynamic/datadog_profiling_ffi.dll	24.93 MB	24.93 MB	0% (0 B) 👌
/libdatadog-x64-windows/debug/dynamic/datadog_profiling_ffi.lib	87.33 KB	87.33 KB	0% (0 B) 👌
/libdatadog-x64-windows/debug/dynamic/datadog_profiling_ffi.pdb	181.51 MB	181.50 MB	-0% (-16.00 KB) 👌
/libdatadog-x64-windows/debug/static/datadog_profiling_ffi.lib	928.21 MB	928.22 MB	+0% (+3.73 KB) 👌
/libdatadog-x64-windows/release/dynamic/datadog_profiling_ffi.dll	8.12 MB	8.12 MB	0% (0 B) 👌
/libdatadog-x64-windows/release/dynamic/datadog_profiling_ffi.lib	87.33 KB	87.33 KB	0% (0 B) 👌
/libdatadog-x64-windows/release/dynamic/datadog_profiling_ffi.pdb	24.03 MB	24.03 MB	0% (0 B) 👌
/libdatadog-x64-windows/release/static/datadog_profiling_ffi.lib	47.96 MB	47.96 MB	0% (0 B) 👌

libdatadog-x86-windows

Artifact	Baseline	Commit	Change
/libdatadog-x86-windows/debug/dynamic/datadog_profiling_ffi.dll	21.62 MB	21.62 MB	0% (0 B) 👌
/libdatadog-x86-windows/debug/dynamic/datadog_profiling_ffi.lib	88.71 KB	88.71 KB	0% (0 B) 👌
/libdatadog-x86-windows/debug/dynamic/datadog_profiling_ffi.pdb	185.58 MB	185.58 MB	0% (0 B) 👌
/libdatadog-x86-windows/debug/static/datadog_profiling_ffi.lib	921.15 MB	921.16 MB	+0% (+3.69 KB) 👌
/libdatadog-x86-windows/release/dynamic/datadog_profiling_ffi.dll	6.27 MB	6.27 MB	0% (0 B) 👌
/libdatadog-x86-windows/release/dynamic/datadog_profiling_ffi.lib	88.71 KB	88.71 KB	0% (0 B) 👌
/libdatadog-x86-windows/release/dynamic/datadog_profiling_ffi.pdb	25.76 MB	25.76 MB	0% (0 B) 👌
/libdatadog-x86-windows/release/static/datadog_profiling_ffi.lib	45.59 MB	45.59 MB	0% (0 B) 👌

x86_64-alpine-linux-musl

Artifact	Baseline	Commit	Change
/x86_64-alpine-linux-musl/lib/libdatadog_profiling.a	74.91 MB	74.91 MB	0% (0 B) 👌
/x86_64-alpine-linux-musl/lib/libdatadog_profiling.so	8.61 MB	8.61 MB	0% (0 B) 👌

x86_64-unknown-linux-gnu

Artifact	Baseline	Commit	Change
/x86_64-unknown-linux-gnu/lib/libdatadog_profiling.a	90.33 MB	90.33 MB	0% (0 B) 👌
/x86_64-unknown-linux-gnu/lib/libdatadog_profiling.so	10.48 MB	10.48 MB	0% (0 B) 👌

Add criterion microbenchmarks isolating `VecMap`, the linear-scan ordered map backing each span's `meta` and `metrics`. Covers insert, get (hit/miss), get_mut, contains_key, iter, dedup (with and without duplicates) and as_deduped_map (borrow vs. allocating path) across representative map sizes (4-64), using `BytesString` keys to match real span usage. Gated behind a new opt-in `bench-internals` feature (mirroring `libdd-sampling`) so the bench is not built by default. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

github-actions Bot added the mini-agent label Jun 16, 2026

yannham force-pushed the yannham/microbenches-vecmap branch 3 times, most recently from 4111119 to bc3de29 Compare June 17, 2026 13:47

yannham and others added 2 commits June 17, 2026 15:58

fix: add missing feature to bench invocation

041db43

yannham force-pushed the yannham/microbenches-vecmap branch from bc3de29 to 041db43 Compare June 17, 2026 13:58

yannham marked this pull request as ready for review June 17, 2026 13:58

yannham requested review from a team as code owners June 17, 2026 13:58

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test(trace-utils): add VecMap microbenchmarks#2126

test(trace-utils): add VecMap microbenchmarks#2126
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yannham commented Jun 16, 2026

What does this PR do?

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📚 Documentation Check Results

📦 libdd-trace-utils - 676 warning(s)

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🔒 Cargo Deny Results

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