Skip to content

[gpum] Derive gpu.sm_active from GPM SM cycle counters - #57928

Draft
martavicentenavarro wants to merge 1 commit into
mainfrom
martavicente/gpm-sm-active-from-sm-cycles
Draft

martavicentenavarro wants to merge 1 commit into
mainfrom
martavicente/gpm-sm-active-from-sm-cycles

Conversation

@martavicentenavarro

@martavicentenavarro martavicentenavarro commented Oct 9, 2026 •

Copy link
Copy Markdown
Contributor

What does this PR do?

Adds a source for gpu.sm_active computed from the GPM counters SM_CYCLES_ELAPSED (248) and SM_CYCLES_ACTIVE (249) on physical GPUs.

NVML returns these counters as cumulative values at Sample2 (not as the difference between the two samples), so the GPM collector keeps the previous reading and reports 100 * Δactive / Δelapsed.

  • Low priority by default (fallback only), High with the new gpu.prefer_sm_cycles_sm_active option.
  • Not computed when gpu.legacy_sm_active is enabled (the legacy value takes precedence) nor on MIG devices, where the counters haven't been validated.
  • RemoveDuplicateSamples now resolves equal-priority ties by collector name instead of map iteration order, so sm_active can't alternate between the ebpf and gpm sources at Low. No other metric is affected: there were no equal-priority ties across collectors before this change.
  • The counter IDs are defined locally because go-nvml v0.13.1-0 stops at ID 210.

Motivation

AXT-33

Describe how you validated your changes

Unit tests

Manual validation on an H100 80GB HBM3 (driver 595.91.07, NVML 13.595.91.07) with agent check gpu:

  • Querying NVML directly confirmed the counters are cumulative and that the value is returned for Sample2.
  • Idle: sm_active = 0.
  • gpu-burner at 60% (gpu-burner --run_time 300 auto --target_sm 60):
    • default config: sm_active = 61–62 from the sampling source;
    • gpu.prefer_sm_cycles_sm_active: true: sm_active = 59.3–59.6 from the new source.
  • With 33 of 132 SMs busy: the new source reports 25%, while gr_engine_active is ~100%.
  • 300 windows under full saturation: Δactive never exceeded Δelapsed.

Additional Notes

  • The derived value is the same as GPM_METRIC_SM_UTIL (SM activity averaged over all SMs), not the percentage of time any SM was active, so with the option enabled gpu.sm_active matches gpu.sm_utilization.
  • With the default config the new source adds two GpmMetricsGet calls per GPM device per run, and its sample is deduplicated, which increases duplicate_metrics telemetry by one per device.
  • Not validated on MIG (disabled there) nor with system-probe/ebpf on hardware.

Compute gpu.sm_active on physical GPUs from the raw GPM SM_CYCLES_ELAPSED
(248) and SM_CYCLES_ACTIVE (249) counters, as the ratio of their deltas
between consecutive samples. NVML returns these counters as cumulative
values at Sample2, so the collector keeps the previous reading. The
result equals GPM_METRIC_SM_UTIL.

The source has low priority by default and high priority with the new
gpu.prefer_sm_cycles_sm_active option. It is not computed when
gpu.legacy_sm_active is enabled, nor on MIG devices, where the counters
haven't been validated. Equal-priority ties in RemoveDuplicateSamples
are now resolved deterministically by collector name.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
@github-actions github-actions Bot added the medium review PR review might take time label Oct 9, 2026

@github-actions github-actions Bot left a comment

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

AI review by Codex (OpenAI) - workflow run

The patch is correct. No actionable issues were found in the counter calculations, source priority handling, configuration wiring, or tests. Validation was limited to static review; tests were not run in the read-only environment.

@datadog-prod-us1-6

datadog-prod-us1-6 Bot commented Oct 9, 2026 •

Copy link
Copy Markdown
Contributor

🎯 Code Coverage (details)
• Patch Coverage: 97.30%
• Overall Coverage: 58.62% (+0.01%)

This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 189db58 | Docs | Give us feedback!

@dd-octo-sts

dd-octo-sts Bot commented Oct 9, 2026

Copy link
Copy Markdown
Contributor

Files inventory check summary

File checks results against ancestor 66e6c51f:

Results for datadog-agent_7.86.0~devel.git.306.189db58.pipeline.143779268-1_amd64.deb:

No change detected

Results for datadog-iot-agent_7.86.0~devel.git.306.189db58.pipeline.143779268-1_amd64.deb:

No change detected

@dd-octo-sts

dd-octo-sts Bot commented Oct 9, 2026

Copy link
Copy Markdown
Contributor

Static quality checks

✅ Please find below the results from static quality gates
Comparison made with ancestor 66e6c51
📊 Static Quality Gates Dashboard
🔗 SQG Job

Successful checks

Info

Quality gate Change Size (prev → curr → max)
✅ agent_deb_amd64 +8.41 KiB (0.00% increase, -0.16% of buffer) 755.256 → 755.264 → 760.520
✅ agent_deb_amd64_fips +12.41 KiB (0.00% increase, -0.23% of buffer) 688.278 → 688.290 → 693.570
✅ agent_rpm_amd64 +8.41 KiB (0.00% increase, -0.16% of buffer) 755.240 → 755.248 → 760.500
✅ agent_rpm_amd64_fips +12.41 KiB (0.00% increase, -0.23% of buffer) 688.261 → 688.274 → 693.550
✅ agent_rpm_arm64 +8.4 KiB (0.00% increase, -0.15% of buffer) 725.784 → 725.793 → 731.100
✅ agent_rpm_arm64_fips +8.06 KiB (0.00% increase, -0.15% of buffer) 664.371 → 664.379 → 669.740
✅ agent_suse_amd64 +8.41 KiB (0.00% increase, -0.16% of buffer) 755.240 → 755.248 → 760.500
✅ agent_suse_amd64_fips +12.41 KiB (0.00% increase, -0.23% of buffer) 688.261 → 688.274 → 693.550
✅ agent_suse_arm64 +8.4 KiB (0.00% increase, -0.15% of buffer) 725.784 → 725.793 → 731.100
✅ agent_suse_arm64_fips +8.06 KiB (0.00% increase, -0.15% of buffer) 664.371 → 664.379 → 669.740
✅ docker_agent_amd64 +8.41 KiB (0.00% increase, -0.16% of buffer) 811.423 → 811.431 → 816.720
✅ docker_agent_arm64 +8.41 KiB (0.00% increase, -0.15% of buffer) 806.590 → 806.598 → 811.970
✅ docker_agent_jmx_amd64 +8.42 KiB (0.00% increase, -0.16% of buffer) 1002.292 → 1002.301 → 1007.590
✅ docker_agent_jmx_arm64 +8.4 KiB (0.00% increase, -0.15% of buffer) 986.240 → 986.248 → 991.620
✅ docker_host_profiler_arm64 -64.22 KiB (0.02% reduction, +8.77% of buffer) 319.865 → 319.802 → 320.580
18 successful checks with minimal change (< 2 KiB)
Quality gate Current Size
✅ agent_heroku_amd64 319.145 MiB
✅ agent_msi 653.833 MiB
✅ docker_cws_instrumentation_amd64 7.443 MiB
✅ docker_cws_instrumentation_arm64 6.877 MiB
✅ docker_dogstatsd_amd64 39.543 MiB
✅ docker_dogstatsd_arm64 37.629 MiB
✅ docker_host_profiler_amd64 308.722 MiB
✅ dogstatsd_deb_amd64 30.290 MiB
✅ dogstatsd_deb_arm64 28.278 MiB
✅ dogstatsd_rpm_amd64 30.290 MiB
✅ dogstatsd_suse_amd64 30.290 MiB
✅ iot_agent_deb_amd64 47.371 MiB
✅ iot_agent_deb_arm64 43.838 MiB
✅ iot_agent_deb_armhf 44.653 MiB
✅ iot_agent_rpm_amd64 47.372 MiB
✅ iot_agent_suse_amd64 47.371 MiB
✅ docker_cluster_agent_amd64 211.197 MiB
✅ docker_cluster_agent_arm64 224.162 MiB

@cit-pr-commenter-54b7da

Copy link
Copy Markdown

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Job ID: bb0ad39f-d238-46b1-820a-a7790fcc7085

Baseline: 66e6c51
Comparison: 189db58
Diff

Optimization Goals: ✅ No significant changes detected

Fine details of change detection per experiment

perf experiment goal Δ mean % Δ mean % CI trials links
➖ dsd_uds_10mb_3k_timestamped_contexts_memory memory utilization +1.62 [+1.40, +1.84] 1 Logs
➖ quality_gate_security_no_fs_load memory utilization +0.26 [+0.19, +0.34] 1 Logs bounds checks dashboard
➖ quality_gate_idle memory utilization +0.26 [+0.21, +0.30] 1 Logs bounds checks dashboard
➖ dsd_uds_10mb_3k_timestamped_contexts_cpu % cpu utilization -0.05 [-0.29, +0.19] 1 Logs
➖ quality_gate_idle_all_features memory utilization -0.07 [-0.15, +0.00] 1 Logs bounds checks dashboard
➖ quality_gate_security_idle memory utilization -0.18 [-0.21, -0.14] 1 Logs bounds checks dashboard
➖ python_openmetrics % cpu utilization -0.22 [-0.90, +0.46] 1 Logs bounds checks dashboard
➖ quality_gate_metrics_logs memory utilization -0.38 [-0.60, -0.15] 1 Logs bounds checks dashboard
➖ quality_gate_logs % cpu utilization -0.49 [-1.34, +0.36] 1 Logs bounds checks dashboard
➖ quality_gate_security_mean_fs_load memory utilization -0.58 [-0.62, -0.55] 1 Logs bounds checks dashboard
➖ quality_gate_private_action_runner memory utilization -0.63 [-0.75, -0.51] 1 Logs bounds checks dashboard
➖ dsd_uds_client_drop_detector_cpu % cpu utilization -0.99 [-1.48, -0.49] 1 Logs

Bounds Checks: ✅ Passed

perf experiment bounds_check_name replicates_passed observed_value links
✅ python_openmetrics checks_execution_time 10/10 80.05 ≤ 100 bounds checks dashboard
✅ python_openmetrics cpu_usage 10/10 1340.66 ≤ 1500 bounds checks dashboard
✅ python_openmetrics memory_usage 10/10 4.31GiB ≤ 4.75GiB bounds checks dashboard
✅ quality_gate_idle intake_connections 10/10 4 ≤ 5 bounds checks dashboard
✅ quality_gate_idle memory_usage 10/10 179.54MiB ≤ 181MiB bounds checks dashboard
✅ quality_gate_idle total_bytes_received 10/10 774.59KiB ≤ 819.20KiB bounds checks dashboard
✅ quality_gate_idle_all_features intake_connections 10/10 2 ≤ 5 bounds checks dashboard
✅ quality_gate_idle_all_features memory_usage 10/10 471.30MiB ≤ 542MiB bounds checks dashboard
✅ quality_gate_idle_all_features total_bytes_received 10/10 1.14MiB ≤ 1.25MiB bounds checks dashboard
✅ quality_gate_logs intake_connections 10/10 18 ≤ 40 bounds checks dashboard
✅ quality_gate_logs memory_usage 10/10 212.05MiB ≤ 228MiB bounds checks dashboard
✅ quality_gate_logs missed_bytes 10/10 0B = 0B bounds checks dashboard
✅ quality_gate_logs total_bytes_received 10/10 263.88MiB ≤ 292MiB bounds checks dashboard
✅ quality_gate_metrics_logs cpu_usage 10/10 371.56 ≤ 2000 bounds checks dashboard
✅ quality_gate_metrics_logs intake_connections 10/10 20 ≤ 40 bounds checks dashboard
✅ quality_gate_metrics_logs memory_usage 10/10 412.82MiB ≤ 455MiB bounds checks dashboard
✅ quality_gate_metrics_logs missed_bytes 10/10 0B = 0B bounds checks dashboard
✅ quality_gate_metrics_logs total_bytes_received 10/10 0.95GiB ≤ 1.04GiB bounds checks dashboard
✅ quality_gate_private_action_runner memory_usage 10/10 73.62MiB ≤ 77MiB bounds checks dashboard
✅ quality_gate_security_idle cpu_usage 10/10 30.57 ≤ 100 bounds checks dashboard
✅ quality_gate_security_idle memory_usage 10/10 326.95MiB ≤ 357MiB bounds checks dashboard
✅ quality_gate_security_mean_fs_load cpu_usage 10/10 63.11 ≤ 200 bounds checks dashboard
✅ quality_gate_security_mean_fs_load memory_usage 10/10 306.43MiB ≤ 337MiB bounds checks dashboard
✅ quality_gate_security_no_fs_load cpu_usage 10/10 22.62 ≤ 100 bounds checks dashboard
✅ quality_gate_security_no_fs_load memory_usage 10/10 338.43MiB ≤ 348MiB bounds checks dashboard

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".

CI Pass/Fail Decision

✅ Passed. All Quality Gates passed.

  • quality_gate_private_action_runner, bounds check memory_usage: 10/10 replicas passed. Gate passed.
  • quality_gate_security_idle, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
  • quality_gate_security_idle, bounds check memory_usage: 10/10 replicas passed. Gate passed.
  • quality_gate_idle, bounds check memory_usage: 10/10 replicas passed. Gate passed.
  • quality_gate_idle, bounds check intake_connections: 10/10 replicas passed. Gate passed.
  • quality_gate_idle, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
  • quality_gate_idle_all_features, bounds check intake_connections: 10/10 replicas passed. Gate passed.
  • quality_gate_idle_all_features, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
  • quality_gate_idle_all_features, bounds check memory_usage: 10/10 replicas passed. Gate passed.
  • quality_gate_security_mean_fs_load, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
  • quality_gate_security_mean_fs_load, bounds check memory_usage: 10/10 replicas passed. Gate passed.
  • quality_gate_metrics_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
  • quality_gate_metrics_logs, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
  • quality_gate_metrics_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
  • quality_gate_metrics_logs, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
  • quality_gate_metrics_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
  • quality_gate_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
  • quality_gate_logs, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
  • quality_gate_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
  • quality_gate_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
  • quality_gate_security_no_fs_load, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
  • quality_gate_security_no_fs_load, bounds check memory_usage: 10/10 replicas passed. Gate passed.

This branch has not been deployed

No deployments
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

Projects

None yet

Development

Successfully merging this pull request may close these issues.

1 participant