enhancement(datadog encoder): support for metrics v3 protocol

[tobz]

Summary

Change Type

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

How did you test this PR?

References

[tobz]

• enhancement(datadog encoder): support for metrics v3 protocol #1175 👈 (View in Graphite)
• main

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[pr-commenter]

Binary Size Analysis (Agent Data Plane)

Target: 2ae2e93 (baseline) vs 79cdda1 (comparison) diff
Analysis Type: Stripped binaries (debug symbols excluded)
Baseline Size: 26.95 MiB
Comparison Size: 27.10 MiB
Size Change: +147.50 KiB (+0.53%)
Pass/Fail Threshold: +5%
Result: PASSED ✅

Changes by Module

Module	File Size	Symbols
saluki_components::encoders::datadog	+72.27 KiB	349
core	+38.43 KiB	8799
hashbrown	+9.67 KiB	338
saluki_common::task::instrument	+7.60 KiB	72
anyhow	+6.48 KiB	1257
[sections]	+6.18 KiB	9
[Unmapped]	-4.81 KiB	1
saluki_components::common::datadog	-4.51 KiB	325
http	+3.85 KiB	297
agent_data_plane::cli::run	+2.50 KiB	70
saluki_io::compression::Compressor<W>	+2.49 KiB	3
serde_core	+2.39 KiB	328
saluki_io::net::util	+2.25 KiB	118
uuid	+1.86 KiB	4
agent_data_plane::components::apm_onboarding	-1.26 KiB	34
saluki_components::transforms::dogstatsd_mapper	-976 B	18
hyper	-882 B	335
tokio	+745 B	2132
saluki_components::sources::otlp	-520 B	164
serde_json	+514 B	170

Detailed Symbol Changes

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  [NEW] +1.79Mi  [NEW] +1.79Mi    std::thread::local::LocalKey<T>::with::he5041c9550d94e3a
  +1.1%  +142Ki  +1.2%  +127Ki    [21757 Others]
  [NEW]  +116Ki  [NEW]  +116Ki    agent_data_plane::cli::run::create_topology::_{{closure}}::he20aec8b6313e3e4
  [NEW] +84.5Ki  [NEW] +84.4Ki    agent_data_plane::internal::control_plane::spawn_control_plane::_{{closure}}::h845aa650a9337a27
  [NEW] +65.0Ki  [NEW] +64.9Ki    saluki_components::common::datadog::io::run_endpoint_io_loop::_{{closure}}::hc2f8bf0da9d3b135
  [NEW] +62.3Ki  [NEW] +62.2Ki    agent_data_plane::main::_{{closure}}::hff1a2452bd2228b1
  [NEW] +57.8Ki  [NEW] +57.6Ki    agent_data_plane::cli::run::handle_run_command::_{{closure}}::hd9a848f2ba8f7232
  [NEW] +48.9Ki  [NEW] +48.8Ki    saluki_app::bootstrap::AppBootstrapper::bootstrap::_{{closure}}::he34c8a7699d30664
  [NEW] +47.6Ki  [NEW] +47.5Ki    moka::sync::base_cache::Inner<K,V,S>::do_run_pending_tasks::h088d17aac68027fc
  [NEW] +46.1Ki  [NEW] +45.9Ki    _<saluki_components::forwarders::otlp::OtlpForwarder as saluki_core::components::forwarders::Forwarder>::run::_{{closure}}::h9462c1f6ca3afc12
  [NEW] +46.0Ki  [NEW] +45.8Ki    _<saluki_components::destinations::prometheus::Prometheus as saluki_core::components::destinations::Destination>::run::_{{closure}}::h9fe629aec157033f
  [DEL] -45.8Ki  [DEL] -45.6Ki    _<saluki_components::forwarders::otlp::OtlpForwarder as saluki_core::components::forwarders::Forwarder>::run::_{{closure}}::hbf7fc5062752441c
  [DEL] -45.9Ki  [DEL] -45.7Ki    _<saluki_components::destinations::prometheus::Prometheus as saluki_core::components::destinations::Destination>::run::_{{closure}}::he3513d7b2ba18303
  [DEL] -47.7Ki  [DEL] -47.6Ki    moka::sync::base_cache::Inner<K,V,S>::do_run_pending_tasks::ha97a2f55834f17a3
  [DEL] -48.8Ki  [DEL] -48.7Ki    saluki_app::bootstrap::AppBootstrapper::bootstrap::_{{closure}}::hbb5d0d8e944d3a21
  [DEL] -57.8Ki  [DEL] -57.7Ki    agent_data_plane::cli::run::handle_run_command::_{{closure}}::hd8d13580d16cc8a3
  [DEL] -62.3Ki  [DEL] -62.2Ki    agent_data_plane::main::_{{closure}}::h1c7c640002ce8ad1
  [DEL] -62.8Ki  [DEL] -62.6Ki    saluki_components::common::datadog::io::run_endpoint_io_loop::_{{closure}}::h73e45ba190fbc213
  [DEL] -84.5Ki  [DEL] -84.4Ki    agent_data_plane::internal::control_plane::spawn_control_plane::_{{closure}}::heace61ab0f2bde0c
  [DEL]  -113Ki  [DEL]  -113Ki    agent_data_plane::cli::run::create_topology::_{{closure}}::h6a8b41fa76a89e2c
  [DEL] -1.79Mi  [DEL] -1.79Mi    std::thread::local::LocalKey<T>::with::h0d8770940d38805b
  +0.5%  +147Ki  +0.5%  +133Ki    TOTAL

[pr-commenter]

Regression Detector (Agent Data Plane)

Regression Detector Results

Run ID: 7789da6f-de35-4be2-8e84-5b902e6613bc

Baseline: 2ae2e93
Comparison: 79cdda1
Diff

❌ Experiments with retried target crashes

This is a critical error. One or more replicates failed with a non-zero exit code. These replicates may have been retried. See Replicate Execution Details for more information.

• otlp_ingest_traces_5mb_memory
• dsd_uds_512kb_3k_contexts_memory
• otlp_ingest_logs_5mb_cpu

Optimization Goals: ✅ No significant changes detected

Experiments ignored for regressions

Regressions in experiments with settings containing erratic: true are ignored.

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	otlp_ingest_logs_5mb_cpu	% cpu utilization	+1.92	[-3.37, +7.20]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_logs_5mb_throughput	ingress throughput	-0.03	[-0.16, +0.10]	1	(metrics) (profiles) (logs)
✅	otlp_ingest_logs_5mb_memory	memory utilization	-13.84	[-14.44, -13.23]	1	(metrics) (profiles) (logs)

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	dsd_uds_512kb_3k_contexts_cpu	% cpu utilization	+9.29	[-48.58, +67.16]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_logs_5mb_cpu	% cpu utilization	+1.92	[-3.37, +7.20]	1	(metrics) (profiles) (logs)
➖	quality_gates_rss_idle	memory utilization	+1.03	[+0.98, +1.08]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_traces_5mb_cpu	% cpu utilization	+0.87	[-1.88, +3.63]	1	(metrics) (profiles) (logs)
➖	dsd_uds_500mb_3k_contexts_throughput	ingress throughput	+0.64	[+0.50, +0.77]	1	(metrics) (profiles) (logs)
➖	dsd_uds_500mb_3k_contexts_memory	memory utilization	+0.41	[+0.22, +0.59]	1	(metrics) (profiles) (logs)
➖	dsd_uds_512kb_3k_contexts_memory	memory utilization	+0.40	[+0.21, +0.58]	1	(metrics) (profiles) (logs)
➖	dsd_uds_100mb_3k_contexts_memory	memory utilization	+0.34	[+0.14, +0.53]	1	(metrics) (profiles) (logs)
➖	quality_gates_rss_dsd_heavy	memory utilization	+0.24	[+0.11, +0.36]	1	(metrics) (profiles) (logs)
➖	quality_gates_rss_dsd_ultraheavy	memory utilization	+0.22	[+0.10, +0.35]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_metrics_5mb_memory	memory utilization	+0.15	[-0.12, +0.41]	1	(metrics) (profiles) (logs)
➖	dsd_uds_1mb_3k_contexts_memory	memory utilization	+0.09	[-0.10, +0.28]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_traces_5mb_memory	memory utilization	+0.05	[-0.19, +0.29]	1	(metrics) (profiles) (logs)
➖	quality_gates_rss_dsd_medium	memory utilization	+0.03	[-0.17, +0.22]	1	(metrics) (profiles) (logs)
➖	dsd_uds_100mb_3k_contexts_throughput	ingress throughput	+0.01	[-0.03, +0.05]	1	(metrics) (profiles) (logs)
➖	dsd_uds_512kb_3k_contexts_throughput	ingress throughput	+0.01	[-0.05, +0.06]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_traces_5mb_throughput	ingress throughput	+0.01	[-0.08, +0.09]	1	(metrics) (profiles) (logs)
➖	dsd_uds_10mb_3k_contexts_throughput	ingress throughput	+0.00	[-0.15, +0.16]	1	(metrics) (profiles) (logs)
➖	dsd_uds_1mb_3k_contexts_throughput	ingress throughput	+0.00	[-0.06, +0.06]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_metrics_5mb_throughput	ingress throughput	-0.02	[-0.15, +0.11]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_logs_5mb_throughput	ingress throughput	-0.03	[-0.16, +0.10]	1	(metrics) (profiles) (logs)
➖	quality_gates_rss_dsd_low	memory utilization	-0.12	[-0.28, +0.04]	1	(metrics) (profiles) (logs)
➖	dsd_uds_10mb_3k_contexts_memory	memory utilization	-0.42	[-0.61, -0.22]	1	(metrics) (profiles) (logs)
➖	dsd_uds_10mb_3k_contexts_cpu	% cpu utilization	-0.70	[-29.22, +27.82]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_metrics_5mb_cpu	% cpu utilization	-0.71	[-6.59, +5.17]	1	(metrics) (profiles) (logs)
➖	dsd_uds_500mb_3k_contexts_cpu	% cpu utilization	-0.81	[-2.14, +0.53]	1	(metrics) (profiles) (logs)
➖	dsd_uds_1mb_3k_contexts_cpu	% cpu utilization	-1.33	[-53.84, +51.18]	1	(metrics) (profiles) (logs)
➖	dsd_uds_100mb_3k_contexts_cpu	% cpu utilization	-2.88	[-8.59, +2.82]	1	(metrics) (profiles) (logs)
✅	otlp_ingest_logs_5mb_memory	memory utilization	-13.84	[-14.44, -13.23]	1	(metrics) (profiles) (logs)

Bounds Checks: ✅ Passed

perf	experiment	bounds_check_name	replicates_passed	links
✅	quality_gates_rss_dsd_heavy	memory_usage	10/10	(metrics) (profiles) (logs)
✅	quality_gates_rss_dsd_low	memory_usage	10/10	(metrics) (profiles) (logs)
✅	quality_gates_rss_dsd_medium	memory_usage	10/10	(metrics) (profiles) (logs)
✅	quality_gates_rss_dsd_ultraheavy	memory_usage	10/10	(metrics) (profiles) (logs)
✅	quality_gates_rss_idle	memory_usage	10/10	(metrics) (profiles) (logs)

Explanation

Confidence level: 90.00%
Effect size tolerance: |Δ mean %| ≥ 5.00%

Performance changes are noted in the perf column of each table:

• ✅ = significantly better comparison variant performance
• ❌ = significantly worse comparison variant performance
• ➖ = no significant change in performance

A regression test is an A/B test of target performance in a repeatable rig, where "performance" is measured as "comparison variant minus baseline variant" for an optimization goal (e.g., ingress throughput). Due to intrinsic variability in measuring that goal, we can only estimate its mean value for each experiment; we report uncertainty in that value as a 90.00% confidence interval denoted "Δ mean % CI".

For each experiment, we decide whether a change in performance is a "regression" -- a change worth investigating further -- if all of the following criteria are true:

1. Its estimated |Δ mean %| ≥ 5.00%, indicating the change is big enough to merit a closer look.

2. Its 90.00% confidence interval "Δ mean % CI" does not contain zero, indicating that if our statistical model is accurate, there is at least a 90.00% chance there is a difference in performance between baseline and comparison variants.

3. Its configuration does not mark it "erratic".

Replicate Execution Details

We run multiple replicates for each experiment/variant. However, we allow replicates to be automatically retried if there are any failures, up to 8 times, at which point the replicate is marked dead and we are unable to run analysis for the entire experiment. We call each of these attempts at running replicates a replicate execution. This section lists all replicate executions that failed due to the target crashing or being oom killed.

Note: In the below tables we bucket failures by experiment, variant, and failure type. For each of these buckets we list out the replicate indexes that failed with an annotation signifying how many times said replicate failed with the given failure mode. In the below example the baseline variant of the experiment named experiment_with_failures had two replicates that failed by oom kills. Replicate 0, which failed 8 executions, and replicate 1 which failed 6 executions, all with the same failure mode.

Experiment	Variant	Replicates	Failure	Logs	Debug Dashboard
experiment_with_failures	baseline	0 (x8) 1 (x6)	Oom killed		Debug Dashboard

The debug dashboard links will take you to a debugging dashboard specifically designed to investigate replicate execution failures.

❌ Retried Normal Replicate Execution Failures (non-profiling)

Experiment	Variant	Replicates	Failure	Debug Dashboard
dsd_uds_512kb_3k_contexts_memory	comparison	9	Failed to shutdown when requested	Debug Dashboard
otlp_ingest_logs_5mb_cpu	comparison	7	Failed to shutdown when requested	Debug Dashboard
otlp_ingest_traces_5mb_memory	comparison	8	Failed to shutdown when requested	Debug Dashboard

❌ Retried Profiling Replicate Execution Failures (target internal profiling)

Note: Profiling replicas may still be executing. See the debug dashboard for up to date status.

Experiment	Variant	Replicates	Failure	Debug Dashboard
otlp_ingest_logs_5mb_cpu	comparison	10	Failed to shutdown when requested	Debug Dashboard

[tobz]

This is temporarily blocked on there being a version of the Datadog Agent for us to test against in correctness tests that has up-to-date v3 metrics support.

Currently, we're hitting an issue related to rate intervals being delta encoded when they shouldn't be. That bug is fixed in DataDog/datadog-agent#45825 but won't be released until 7.77: roughly 2 weeks from now before an RC is available to use. We can potentially do a hacky image build or something for keep going in the meantime and then switch back to a proper Agent version once available, we'll see.