fix(datadog): fix encoder deadlock under bursty v3 metrics

[tobz]

Summary

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

How did you test this PR?

References

[tobz]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• fix(datadog): fix encoder deadlock under bursty v3 metrics #2229 👈 (View in Graphite)
• fix(metrics): skip V3 encoding for V2-only endpoints #2227
• chore(config): make Core Agent config authoritative for V3 routing #2226
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[pr-commenter]

Binary Size Analysis (Agent Data Plane)

Baseline: 032b9ac · Comparison: 8ec3099 · diff
Analysis Configuration: stripped binaries · Pass/Fail Threshold: +5%
Sizes: 40.83 MiB (baseline) vs 40.82 MiB (comparison)
Size Change: -13.18 KiB (-0.03%)

✅ Binary size difference within threshold

Changes by Module

Module	File Size	Symbols
tracing	-112.91 KiB	39
saluki_common::resource_tracking::groups	+98.94 KiB	22
saluki_components::common::datadog	+40.22 KiB	112
figment	-37.57 KiB	157
saluki_components::encoders::datadog	+24.43 KiB	93
tokio	-22.46 KiB	579
anon.1c766fa05dd13eba06da95c69824d6af.995.llvm.16845278109024732812	-17.36 KiB	1
anon.1c5af32c575c0d14ae778d58023b5abf.0.llvm.10081054402879163701	+17.36 KiB	1
anon.1c766fa05dd13eba06da95c69824d6af.995.llvm.2183139281678763661	+17.36 KiB	1
hashbrown	+17.28 KiB	181
anon.ad88aefe8160b8dedfdf5305e59f030a.513.llvm.6948463008055664385	-17.27 KiB	1
hyper	+16.68 KiB	93
axum	-15.11 KiB	107
serde_core	+14.54 KiB	189
hyper_util	-14.08 KiB	8
core	-14.03 KiB	2774
saluki_common::cache::CacheBuilder<K,V,W,H>	-13.58 KiB	3
saluki_components::sources::otlp	+13.32 KiB	32
chrono	-12.96 KiB	10
tokio_rustls	-12.72 KiB	12

Detailed Symbol Changes

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  [NEW] +61.4Ki  [NEW] +61.3Ki    saluki_components::common::datadog::io::run_endpoint_io_loop::_{{closure}}::h9313854c2f2a044f
  [NEW] +33.9Ki  [NEW] +33.6Ki    _<saluki_components::common::datadog::config::_::<impl serde_core::de::Deserialize for saluki_components::common::datadog::config::ForwarderConfiguration>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map::h215858157e52a210
  +0.3% +32.7Ki  +0.0% +1.83Ki    [15695 Others]
  [NEW] +17.9Ki  [NEW] +17.7Ki    saluki_components::encoders::datadog::metrics::encode_and_flush_v3_payload_requests::_{{closure}}::hbbcbc6fe0e18aea2
  [NEW] +17.4Ki  [NEW]     +76    anon.1c5af32c575c0d14ae778d58023b5abf.0.llvm.10081054402879163701
  [NEW] +17.4Ki  [NEW] +17.3Ki    anon.1c766fa05dd13eba06da95c69824d6af.995.llvm.2183139281678763661
  [NEW] +13.0Ki  [NEW] +12.9Ki    _<saluki_common::resource_tracking::groups::Tracked<Inner> as core::future::future::Future>::poll::hb237d9782d5fe43d
  [NEW] +12.7Ki  [NEW] +12.5Ki    _<saluki_components::encoders::datadog::metrics::DatadogMetricsConfiguration as saluki_core::components::encoders::builder::EncoderBuilder>::build::_{{closure}}::h5ca37cf4fddb78c4
 +24e2% +12.6Ki +40e2% +12.6Ki    _<saluki_components::transforms::trace_obfuscation::TraceObfuscation as saluki_core::components::transforms::SynchronousTransform>::transform_buffer::h4694da026393f90f
  [DEL] -12.2Ki  [DEL] -12.0Ki    saluki_components::encoders::datadog::metrics::encode_v3_payload_requests::_{{closure}}::h3df3e9d9de0b5978
  [DEL] -12.2Ki  [DEL]     -81    anon.ad88aefe8160b8dedfdf5305e59f030a.665.llvm.6948463008055664385
  [DEL] -12.4Ki  [DEL] -12.3Ki    _<chrono::format::formatting::DelayedFormat<I> as core::fmt::Display>::fmt::h46581aaf02582bbc
  [DEL] -13.5Ki  [DEL] -13.4Ki    _<tracing::instrument::Instrumented<T> as core::future::future::Future>::poll::h0a965208a434db48
 -98.3% -14.2Ki -99.7% -14.2Ki    _<saluki_components::transforms::trace_sampler::TraceSampler as saluki_core::components::transforms::SynchronousTransform>::transform_buffer::hd2ecf69cf1bd8db4
  [DEL] -14.3Ki  [DEL] -14.1Ki    _<figment::value::de::ConfiguredValueDe<I> as serde_core::de::Deserializer>::deserialize_any::h2e163da9da896fb8
  [DEL] -14.9Ki  [DEL] -14.8Ki    _<figment::value::de::ConfiguredValueDe<I> as serde_core::de::Deserializer>::deserialize_struct::ha36113e815a9c1ca
  [DEL] -17.3Ki  [DEL]     -76    anon.ad88aefe8160b8dedfdf5305e59f030a.513.llvm.6948463008055664385
  [DEL] -17.4Ki  [DEL] -17.3Ki    anon.1c766fa05dd13eba06da95c69824d6af.995.llvm.16845278109024732812
  [DEL] -19.6Ki  [DEL] -19.5Ki    saluki_components::transforms::apm_stats::ApmStats::process_trace::h0c7467fe110ac0a8
  [DEL] -24.3Ki  [DEL] -24.2Ki    saluki_components::transforms::trace_obfuscation::TraceObfuscation::obfuscate_span::hca56db06df8fb52f
  [DEL] -59.9Ki  [DEL] -59.7Ki    saluki_components::common::datadog::io::run_endpoint_io_loop::_{{closure}}::h3e35c9d992da4100
  -0.0% -13.2Ki  -0.1% -31.8Ki    TOTAL

[datadog-prod-us1-4]

✨ Unblock PR with BitsAI

⚠️ Warnings

🚦 1 Pipeline job failed

DataDog/saluki | run-benchmarks-adp     

Useful? React with 👍 / 👎

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 8ec3099 | Docs | Datadog PR Page | Give us feedback!}

[pr-commenter]

Regression Detector (Agent Data Plane)

Run ID: 33891651-eec7-4b20-8b1c-57b9bfe68419
Baseline: 032b9ac5 · Comparison: 8ec30999 · diff

Optimization Goals: ❌ 2 regressions detected

experiment	goal	Δ mean %	links
quality_gates_rss_dsd_ultraheavy (erratic)	memory	🔴 +11.02	metrics profiles logs
quality_gates_rss_dsd_heavy (erratic)	memory	🔴 +8.19	metrics profiles logs

Fine details of change detection per experiment (3)

Experiments configured erratic: true are tagged (ignored) and skipped when determining which experiments regressed or improved. Experiments which are detected as erratic at runtime are tagged (erratic) to flag that the run's sample dispersion was high, but their regression / improvement signal still counts.

experiment	goal	Δ mean %	links
quality_gates_rss_dsd_medium (erratic)	memory	⚪ +2.40	metrics profiles logs
quality_gates_rss_idle	memory	⚪ +0.60	metrics profiles logs
quality_gates_rss_dsd_low	memory	⚪ +0.18	metrics profiles logs

Bounds Checks: ❌ Failed (5)

experiment	check	replicates	observed	links
quality_gates_rss_dsd_heavy	memory_usage	0/10	❌ 214 MiB ≤ 140 MiB	metrics profiles logs
quality_gates_rss_dsd_low	memory_usage	0/10	❌ 52 MiB ≤ 50 MiB	metrics profiles logs
quality_gates_rss_dsd_medium	memory_usage	0/10	❌ 89.3 MiB ≤ 75 MiB	metrics profiles logs
quality_gates_rss_dsd_ultraheavy	memory_usage	0/10	❌ 292 MiB ≤ 200 MiB	metrics profiles logs
quality_gates_rss_idle	memory_usage	10/10	✅ 31.4 MiB ≤ 40 MiB	metrics profiles logs

Explanation

A change is flagged as a regression when |Δ mean %| > 5.00% in the regressing direction for its optimization goal AND SMP marks the experiment as a regression (is_regression: true). Improvements use the matching criteria for the improving direction. Experiments configured erratic: true (tagged (ignored)) are skipped outright; experiments detected as erratic at runtime (tagged (erratic)) still count, since that flag describes sample dispersion rather than directional certainty. The Δ mean % cell is colored accordingly: 🟢 = improvement, 🔴 = regression, ⚪ = neutral. Reduction in CPU or memory is an improvement; reduction in ingress throughput is a regression.