chore: test libdatadog OTLP gRPC size impact [DO NOT MERGE]

[bm1549]

Description

Temporary CI experiment. Do not merge.

Pins every libdatadog dependency from v42.0.0 to commit 1f2c50a29903ec6dcbf54427d6fc952631662d48, the current head of DataDog/libdatadog#2273. This lets the existing serverless CI measure the resulting Lambda layer size.

Testing

• cargo check --manifest-path src/native/Cargo.toml
• scripts/run-tests --venv 4a90061
• scripts/lint checks
• Serverless Lambda layer-size CI on this draft PR

Risks

None while this remains an unmerged experiment.

The size comparison is from libdatadog v42.0.0 to the PR head, so it includes intervening libdatadog changes. At the pinned commit, the gRPC path is not yet wired into the exporter loop; release LTO may remove unreachable code and understate its eventual shipped cost.

Additional Notes

No Cargo feature gate was added for the new dependencies.

[cit-pr-commenter-54b7da]

Codeowners resolved as

Resolved from the full PR diff against main using the target branch CODEOWNERS file.
CODEOWNERS team requests not listed below are not required by the current file set.

src/native/Cargo.lock                                                   @DataDog/apm-core-python
src/native/Cargo.toml                                                   @DataDog/apm-core-python

[cit-pr-commenter-54b7da]

Dependency direction analysis

⚠️ Existing dependency direction violations

There are 240 dependency direction violations that already exist on the base branch and have not been changed by this PR.

Show existing violations (showing 5 of 240 highest severity)

ddtrace.internal.tracemethods -×-> ddtrace.trace  (internal-core -> product:tracing, score=135)
ddtrace.llmobs._integrations.bedrock_agents -×-> ddtrace.trace  (product:llmobs -> product:tracing, score=133)
ddtrace.appsec._contrib.django -×-> ddtrace.trace  (product:appsec -> product:tracing, score=133)
ddtrace.internal.test_visibility.api -×-> ddtrace.trace  (product:ci_visibility -> product:tracing, score=133)
ddtrace.internal.ci_visibility.filters -×-> ddtrace.trace  (product:ci_visibility -> product:tracing, score=133)

To see all violations, download the layers-base.json and layers-pr.json artifacts from this CI job and run:

uv run --script scripts/import-analysis/layers.py compare layers-base.json layers-pr.json

[cit-pr-commenter-54b7da]

Circular import analysis

⚠️ Existing circular imports

There are 3 circular imports that already exist on the base branch and have not been changed by this PR.

ddtrace.llmobs -> ddtrace.llmobs._evaluators -> ddtrace.llmobs._evaluators.format -> ddtrace.llmobs._experiment -> ddtrace.llmobs
ddtrace.errortracking._handled_exceptions.bytecode_injector -> ddtrace.errortracking._handled_exceptions.callbacks -> ddtrace.errortracking._handled_exceptions.collector -> ddtrace.errortracking._handled_exceptions.bytecode_reporting -> ddtrace.errortracking._handled_exceptions.bytecode_injector
ddtrace.appsec._asm_request_context -> ddtrace.appsec._iast._iast_request_context_base -> ddtrace.appsec._iast._iast_env -> ddtrace.appsec._iast.reporter -> ddtrace.appsec._exploit_prevention.stack_traces -> ddtrace.appsec._asm_request_context

[datadog-prod-us1-5]

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: bcc27e4 | Docs | View more details | Give us feedback!}

[pr-commenter]

Benchmarks

Benchmark execution time: 2026-08-31 17:23:54

Comparing candidate commit bcc27e4 in PR branch brian.marks/test-libdatadog-otlp-grpc-size with baseline commit 93af8ce in branch main.

📊 Benchmarking dashboard

Found 0 performance improvements and 5 performance regressions! Performance is the same for 575 metrics, 10 unstable metrics, 2 known flaky benchmarks, 16 flaky benchmarks without significant changes.

Explanation

This is an A/B test comparing a candidate commit's performance against that of a baseline commit. Performance changes are noted in the tables below as:

• 🟩 = significantly better candidate vs. baseline
• 🟥 = significantly worse candidate vs. baseline

We compute a confidence interval (CI) over the relative difference of means between metrics from the candidate and baseline commits, considering the baseline as the reference.

If the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD), the change is considered significant.

Feel free to reach out to #apm-benchmarking-platform on Slack if you have any questions.

More details about the CI and significant changes

You can imagine this CI as a range of values that is likely to contain the true difference of means between the candidate and baseline commits.

CIs of the difference of means are often centered around 0%, because often changes are not that big:

---------------------------------(------|---^--------)-------------------------------->
                              -0.6%    0%  0.3%     +1.2%
                                 |          |        |
         lower bound of the CI --'          |        |
sample mean (center of the CI) -------------'        |
         upper bound of the CI ----------------------'

As described above, a change is considered significant if the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD).

For instance, for an execution time metric, this confidence interval indicates a significantly worse performance:

----------------------------------------|---------|---(---------^---------)---------->
                                       0%        1%  1.3%      2.2%      3.1%
                                                  |   |         |         |
       significant impact threshold --------------'   |         |         |
                      lower bound of CI --------------'         |         |
       sample mean (center of the CI) --------------------------'         |
                      upper bound of CI ----------------------------------'

scenario:httppropagationinject-ids_only

• 🟥 execution_time [+2.108µs; +2.269µs] or [+12.800%; +13.784%]

scenario:iastaspects-title_aspect

• 🟥 execution_time [+65.040µs; +70.464µs] or [+24.261%; +26.284%]

scenario:iastaspectsospath-ospathbasename_aspect

• 🟥 execution_time [+118.436µs; +128.043µs] or [+28.160%; +30.444%]

scenario:telemetryaddmetric-1-count-metric-1-times

• 🟥 execution_time [+405.527ns; +442.959ns] or [+14.919%; +16.296%]

scenario:tracer-small

• 🟥 execution_time [+37.900µs; +40.111µs] or [+11.866%; +12.558%]

Unstable benchmarks

These benchmarks have a confidence interval too wide to call a change; treat them as noise rather than signal.

scenario:coreapiscenario-context_with_data_listeners

• unstable execution_time [-755.758ns; +722.259ns] or [-6.913%; +6.607%]

scenario:coreapiscenario-core_dispatch_1_listener

• unstable execution_time [-28.105ns; +38.432ns] or [-4.596%; +6.285%]

scenario:coreapiscenario-core_dispatch_50_listeners

• unstable execution_time [-1598.644ns; +1728.511ns] or [-9.338%; +10.096%]

scenario:coreapiscenario-core_dispatch_exception_listeners

• unstable execution_time [-1410.863ns; +1041.163ns] or [-10.877%; +8.027%]

scenario:coreapiscenario-core_dispatch_listeners

• unstable execution_time [-319.935ns; +335.103ns] or [-8.679%; +9.091%]

scenario:coreapiscenario-core_dispatch_no_args_listeners

• unstable execution_time [-264.676ns; +248.087ns] or [-9.008%; +8.444%]

scenario:coreapiscenario-core_dispatch_with_results_1_listener

• unstable execution_time [-97.951ns; +49.494ns] or [-8.351%; +4.220%]

scenario:coreapiscenario-core_dispatch_with_results_50_listeners

• unstable execution_time [-3730.637ns; +4187.694ns] or [-9.228%; +10.359%]

scenario:coreapiscenario-core_dispatch_with_results_listeners

• unstable execution_time [-725.780ns; +826.628ns] or [-8.949%; +10.192%]

scenario:packagesupdateimporteddependencies-import_many_stdlib_cached

• unstable execution_time [-52.695µs; +65.059µs] or [-8.496%; +10.489%]

Known flaky benchmarks

These benchmarks are marked as flaky and will not trigger a failure. Modify FLAKY_BENCHMARKS_REGEX to control which benchmarks are marked as flaky.

scenario:iastaspects-casefold_noaspect

• 🟥 execution_time [+57.195µs; +61.002µs] or [+22.983%; +24.513%]

scenario:span-start

• 🟥 execution_time [+1.759ms; +2.019ms] or [+13.021%; +14.944%]

Known flaky benchmarks without significant changes:

• scenario:errortrackingflasksqli-baseline
• scenario:flasksimple-iast-get
• scenario:iastaspects-casefold_aspect
• scenario:iastaspects-index_aspect
• scenario:iastaspects-ljust_noaspect
• scenario:iastaspects-lower_aspect
• scenario:iastaspects-replace_aspect
• scenario:iastaspects-swapcase_aspect
• scenario:iastaspects-title_noaspect
• scenario:iastaspects-translate_aspect
• scenario:iastaspects-translate_noaspect
• scenario:iastaspects-upper_noaspect
• scenario:packagespackageforrootmodulemapping-cache_off
• scenario:packagespackageforrootmodulemapping-cache_on
• scenario:sethttpmeta-all-enabled
• scenario:telemetryaddmetric-record-100-metrics