[DEBUG-3986] dyninst/actuator: add a stateful control layer #37841

ajwerner · 2025-06-11T04:34:34Z

This layer orchestrates the lifecycle of programs and how they map to processes. Most of the implementation and testing goes into the state machine and its updates. I suspect it could have a better implementation -- right now it's just a bunch of imperative case crushing. I tried to make up for that with a good deal of testing and testing infrastructure.

The testing comes in two main forms:

TestSnapshot: uses golden files in a yaml DSL to list the set of events that should happen and then reports the state transitions and effects
TestStateMachineProperties: uses random event generation to try to shake out interesting behaviors

Both of these tests rely on invariant checking of the state itself.

In addition to the state, there's the implementation of the Actuator which hooks up the state machine and the effects it generates to real dependencies.

One thing this change makes abundantly clear is the need to have fine-grained error reporting out of ir generation, and then separately a clearer interface for how to report these errors out into the diagnostics flows.

cit-pr-commenter · 2025-06-11T05:20:13Z

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Run ID: daf69cd0-4935-474c-b0d6-35497552a8c0

Baseline: 99942ff
Comparison: 7b3f8a1
Diff

Optimization Goals: ✅ No significant changes detected

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	quality_gate_logs	% cpu utilization	+2.14	[-0.67, +4.96]	1	Logs bounds checks dashboard
➖	tcp_syslog_to_blackhole	ingress throughput	+1.05	[+0.98, +1.11]	1	Logs
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	+0.88	[+0.04, +1.72]	1	Logs
➖	uds_dogstatsd_20mb_12k_contexts_20_senders	memory utilization	+0.73	[+0.66, +0.80]	1	Logs
➖	quality_gate_idle	memory utilization	+0.56	[+0.51, +0.62]	1	Logs bounds checks dashboard
➖	file_tree	memory utilization	+0.55	[+0.39, +0.71]	1	Logs
➖	otlp_ingest_metrics	memory utilization	+0.30	[+0.13, +0.47]	1	Logs
➖	ddot_logs	memory utilization	+0.28	[+0.16, +0.40]	1	Logs
➖	ddot_metrics	memory utilization	+0.13	[+0.01, +0.24]	1	Logs
➖	file_to_blackhole_0ms_latency_http1	egress throughput	+0.10	[-0.46, +0.66]	1	Logs
➖	otlp_ingest_logs	memory utilization	+0.10	[-0.03, +0.23]	1	Logs
➖	file_to_blackhole_300ms_latency	egress throughput	+0.07	[-0.55, +0.70]	1	Logs
➖	file_to_blackhole_0ms_latency_http2	egress throughput	+0.06	[-0.47, +0.59]	1	Logs
➖	file_to_blackhole_1000ms_latency_linear_load	egress throughput	+0.06	[-0.18, +0.30]	1	Logs
➖	file_to_blackhole_500ms_latency	egress throughput	+0.02	[-0.52, +0.57]	1	Logs
➖	file_to_blackhole_1000ms_latency	egress throughput	+0.01	[-0.59, +0.62]	1	Logs
➖	tcp_dd_logs_filter_exclude	ingress throughput	+0.00	[-0.02, +0.02]	1	Logs
➖	uds_dogstatsd_to_api	ingress throughput	-0.01	[-0.28, +0.27]	1	Logs
➖	file_to_blackhole_0ms_latency	egress throughput	-0.06	[-0.64, +0.52]	1	Logs
➖	file_to_blackhole_100ms_latency	egress throughput	-0.10	[-0.62, +0.42]	1	Logs
➖	docker_containers_memory	memory utilization	-0.20	[-0.28, -0.13]	1	Logs
➖	quality_gate_idle_all_features	memory utilization	-0.31	[-0.38, -0.25]	1	Logs bounds checks dashboard
➖	docker_containers_cpu	% cpu utilization	-0.73	[-3.71, +2.24]	1	Logs

Bounds Checks: ✅ Passed

perf	experiment	bounds_check_name	replicates_passed	links
✅	docker_containers_cpu	simple_check_run	10/10
✅	docker_containers_memory	memory_usage	10/10
✅	docker_containers_memory	simple_check_run	10/10
✅	file_to_blackhole_0ms_latency	lost_bytes	10/10
✅	file_to_blackhole_0ms_latency	memory_usage	10/10
✅	file_to_blackhole_0ms_latency_http1	lost_bytes	10/10
✅	file_to_blackhole_0ms_latency_http1	memory_usage	10/10
✅	file_to_blackhole_0ms_latency_http2	lost_bytes	10/10
✅	file_to_blackhole_0ms_latency_http2	memory_usage	10/10
✅	file_to_blackhole_1000ms_latency	memory_usage	10/10
✅	file_to_blackhole_1000ms_latency_linear_load	memory_usage	10/10
✅	file_to_blackhole_100ms_latency	lost_bytes	10/10
✅	file_to_blackhole_100ms_latency	memory_usage	10/10
✅	file_to_blackhole_300ms_latency	lost_bytes	10/10
✅	file_to_blackhole_300ms_latency	memory_usage	10/10
✅	file_to_blackhole_500ms_latency	lost_bytes	10/10
✅	file_to_blackhole_500ms_latency	memory_usage	10/10
✅	quality_gate_idle	intake_connections	10/10	bounds checks dashboard
✅	quality_gate_idle	memory_usage	10/10	bounds checks dashboard
✅	quality_gate_idle_all_features	intake_connections	10/10	bounds checks dashboard
✅	quality_gate_idle_all_features	memory_usage	10/10	bounds checks dashboard
✅	quality_gate_logs	intake_connections	10/10	bounds checks dashboard
✅	quality_gate_logs	lost_bytes	10/10	bounds checks dashboard
✅	quality_gate_logs	memory_usage	10/10	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:

Its estimated |Δ mean %| ≥ 5.00%, indicating the change is big enough to merit a closer look.
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.
Its configuration does not mark it "erratic".

CI Pass/Fail Decision

✅ Passed. All Quality Gates passed.

quality_gate_idle, bounds check intake_connections: 10/10 replicas passed. Gate passed.
quality_gate_idle, bounds check memory_usage: 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 memory_usage: 10/10 replicas passed. Gate passed.
quality_gate_logs, bounds check lost_bytes: 10/10 replicas passed. Gate passed.
quality_gate_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
quality_gate_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.

agent-platform-auto-pr · 2025-06-11T16:29:14Z

Static quality checks

✅ Please find below the results from static quality gates
Comparison made with ancestor 99942ff

Successful checks

Info

	Quality gate	Delta	On disk size (MiB)	Delta	On wire size (MiB)
✅	agent_deb_amd64	$${0}$$	$${696.37}$$ < $${697.37}$$	$${-0.01}$$	$${176.04}$$ < $${177.03}$$
✅	agent_deb_amd64_fips	$${0}$$	$${694.67}$$ < $${695.59}$$	$${+0.05}$$	$${175.55}$$ < $${176.51}$$
✅	agent_heroku_amd64	$${0}$$	$${358.67}$$ < $${359.67}$$	$${-0}$$	$${96.51}$$ < $${97.47}$$
✅	agent_msi	$${+0}$$	$${958.88}$$ < $${959.86}$$	$${-0.04}$$	$${146.27}$$ < $${147.27}$$
✅	agent_rpm_amd64	$${0}$$	$${696.36}$$ < $${697.36}$$	$${-0.03}$$	$${177.57}$$ < $${178.56}$$
✅	agent_rpm_amd64_fips	$${0}$$	$${694.66}$$ < $${695.58}$$	$${+0.02}$$	$${177.46}$$ < $${178.43}$$
✅	agent_rpm_arm64	$${0}$$	$${686.38}$$ < $${687.37}$$	$${+0.05}$$	$${161.09}$$ < $${161.99}$$
✅	agent_rpm_arm64_fips	$${0}$$	$${684.79}$$ < $${685.72}$$	$${-0.02}$$	$${160.2}$$ < $${161.11}$$
✅	agent_suse_amd64	$${0}$$	$${696.36}$$ < $${697.36}$$	$${-0.03}$$	$${177.57}$$ < $${178.56}$$
✅	agent_suse_amd64_fips	$${0}$$	$${694.66}$$ < $${695.58}$$	$${+0.02}$$	$${177.46}$$ < $${178.43}$$
✅	agent_suse_arm64	$${0}$$	$${686.38}$$ < $${687.37}$$	$${+0.05}$$	$${161.09}$$ < $${161.99}$$
✅	agent_suse_arm64_fips	$${0}$$	$${684.79}$$ < $${685.72}$$	$${-0.02}$$	$${160.2}$$ < $${161.11}$$
✅	docker_agent_amd64	$${+0}$$	$${780.16}$$ < $${781.16}$$	$${+0.01}$$	$${268.68}$$ < $${269.63}$$
✅	docker_agent_arm64	$${+0}$$	$${793.63}$$ < $${794.62}$$	$${-0.01}$$	$${256.05}$$ < $${257.0}$$
✅	docker_agent_jmx_amd64	$${-0}$$	$${971.36}$$ < $${972.35}$$	$${+0.01}$$	$${337.65}$$ < $${338.6}$$
✅	docker_agent_jmx_arm64	$${+0}$$	$${973.42}$$ < $${974.41}$$	$${+0.01}$$	$${320.99}$$ < $${321.97}$$
✅	docker_agent_windows1809	$${-0.06}$$	$${1486.95}$$ < $${1488.0}$$	$${+0.11}$$	$${488.11}$$ < $${488.95}$$
✅	docker_agent_windows1809_core	$${-0}$$	$${6216.98}$$ < $${6218.0}$$	$${0}$$	$${2048.0}$$ < $${2049.0}$$
✅	docker_agent_windows1809_core_jmx	$${-22.35}$$	$${6338.55}$$ < $${6361.0}$$	$${0}$$	$${2048.0}$$ < $${2049.0}$$
✅	docker_agent_windows1809_jmx	$${+0}$$	$${1608.65}$$ < $${1609.5}$$	$${-0.02}$$	$${530.34}$$ < $${531.32}$$
✅	docker_agent_windows2022	$${+0.2}$$	$${1506.33}$$ < $${1507.0}$$	$${-0.01}$$	$${500.75}$$ < $${501.7}$$
✅	docker_agent_windows2022_core	$${+0.02}$$	$${6190.29}$$ < $${6311.0}$$	$${0}$$	$${2048.0}$$ < $${2049.0}$$
✅	docker_agent_windows2022_core_jmx	$${+0.06}$$	$${6311.94}$$ < $${6313.0}$$	$${0}$$	$${2048.0}$$ < $${2049.0}$$
✅	docker_agent_windows2022_jmx	$${-0.1}$$	$${1628.05}$$ < $${1628.16}$$	$${-0}$$	$${543.03}$$ < $${543.98}$$
✅	docker_cluster_agent_amd64	$${-0}$$	$${212.84}$$ < $${213.79}$$	$${+0}$$	$${72.38}$$ < $${73.33}$$
✅	docker_cluster_agent_arm64	$${-0}$$	$${228.68}$$ < $${229.64}$$	$${+0}$$	$${68.65}$$ < $${69.6}$$
✅	docker_cws_instrumentation_amd64	$${0}$$	$${7.08}$$ < $${7.12}$$	$${+0}$$	$${2.95}$$ < $${3.29}$$
✅	docker_cws_instrumentation_arm64	$${0}$$	$${6.69}$$ < $${6.92}$$	$${-0}$$	$${2.7}$$ < $${3.07}$$
✅	docker_dogstatsd_amd64	$${+0}$$	$${39.22}$$ < $${39.57}$$	$${+0}$$	$${15.12}$$ < $${15.76}$$
✅	docker_dogstatsd_arm64	$${-0}$$	$${37.88}$$ < $${38.2}$$	$${-0}$$	$${14.53}$$ < $${14.83}$$
✅	dogstatsd_deb_amd64	$${0}$$	$${30.45}$$ < $${31.4}$$	$${+0}$$	$${8.0}$$ < $${8.95}$$
✅	dogstatsd_deb_arm64	$${0}$$	$${29.02}$$ < $${29.97}$$	$${-0}$$	$${6.94}$$ < $${7.89}$$
✅	dogstatsd_rpm_amd64	$${0}$$	$${30.45}$$ < $${31.4}$$	$${-0}$$	$${8.01}$$ < $${8.96}$$
✅	dogstatsd_suse_amd64	$${0}$$	$${30.45}$$ < $${31.4}$$	$${-0}$$	$${8.01}$$ < $${8.96}$$
✅	iot_agent_deb_amd64	$${0}$$	$${50.43}$$ < $${51.38}$$	$${-0}$$	$${12.84}$$ < $${13.79}$$
✅	iot_agent_deb_arm64	$${0}$$	$${47.9}$$ < $${48.85}$$	$${+0}$$	$${11.14}$$ < $${12.09}$$
✅	iot_agent_deb_armhf	$${0}$$	$${47.47}$$ < $${48.42}$$	$${-0}$$	$${11.2}$$ < $${12.16}$$
✅	iot_agent_rpm_amd64	$${0}$$	$${50.43}$$ < $${51.38}$$	$${+0}$$	$${12.86}$$ < $${13.81}$$
✅	iot_agent_rpm_arm64	$${0}$$	$${47.9}$$ < $${48.85}$$	$${-0}$$	$${11.15}$$ < $${12.11}$$
✅	iot_agent_suse_amd64	$${0}$$	$${50.43}$$ < $${51.38}$$	$${+0}$$	$${12.86}$$ < $${13.81}$$

piob-io

Neat tests!

piob-io · 2025-06-12T12:26:57Z

pkg/dyninst/actuator/settings.go

+	// UnregisterProgram unregisters a program from the dispatcher.
+	UnregisterProgram(program ir.ProgramID)
+
+	// HandleMessage handles a message from the dispatcher.


From a registered program?

piob-io · 2025-06-12T12:35:25Z

pkg/dyninst/actuator/state.go

+	baseEvent
+	programID ir.ProgramID
+	err       error
+}


Could IR generation and compilation be combined into a single asynchronous action, that does both, in sequence? They both feel like steps of "probe initialization"? Maybe program loading too?

piob-io · 2025-06-12T12:37:22Z

pkg/dyninst/actuator/update.go

process.go maybe? it's not just update, and I think process might be clearer?

piob-io · 2025-06-12T12:41:23Z

pkg/dyninst/actuator/settings.go

+
+type settings struct {
+	ringBufSize      int
+	dispatcher       Dispatcher


Dispatcher wasn't too clear to me, before diving into code (as there is lots of dispatching going around with state machine). "Sink" maybe to indicate it has to do with dealing with output/results of the whole actuation? Or output or ProbeOutput or ProgramOutput?

Called it MessageSink.

ajwerner · 2025-06-13T17:19:23Z

/merge

dd-devflow · 2025-06-13T17:19:29Z

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2025-06-13 20:49:05 UTC ℹ️ MergeQueue: merge request added to the queue

The expected merge time in main is approximately 1h (p90).

2025-06-13 21:27:01 UTC ℹ️ MergeQueue: This merge request was merged

This layer orchestrates the lifecycle of programs and how they map to processes. Most of the implementation and testing goes into the state machine and its updates. I suspect it could have a better implementation -- right now it's just a bunch of imperative case crushing. I tried to make up for that with a good deal of testing and testing infrastructure. The testing comes in two main forms: - TestSnapshot: uses golden files in a yaml DSL to list the set of events that should happen and then reports the state transitions and effects - TestStateMachineProperties: uses random event generation to try to shake out interesting behaviors Both of these tests rely on invariant checking of the state itself. In addition to the state, there's the implementation of the Actuator which hooks up the state machine and the effects it generates to real dependencies. One thing this change makes abundantly clear is the need to have fine-grained error reporting out of ir generation, and then separately a clearer interface for how to report these errors out into the diagnostics flows.

github-actions bot added the long review PR is complex, plan time to review it label Jun 11, 2025

ajwerner added changelog/no-changelog qa/done QA done before merge and regressions are covered by tests labels Jun 11, 2025

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ajwerner marked this pull request as ready for review June 11, 2025 14:15

ajwerner requested a review from a team as a code owner June 11, 2025 14:15

ajwerner force-pushed the ajwerner/dyninst-actuator branch 2 times, most recently from 3dff4a2 to 779993c Compare June 12, 2025 01:53

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ajwerner mentioned this pull request Jun 12, 2025

[dyninst] Support probe throttling #37911

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ajwerner force-pushed the ajwerner/dyninst-actuator branch from 779993c to 88f2128 Compare June 13, 2025 16:37

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[DEBUG-3986] dyninst/actuator: add a stateful control layer #37841

[DEBUG-3986] dyninst/actuator: add a stateful control layer #37841

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ajwerner commented Jun 11, 2025

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Regression Detector

Regression Detector Results

Optimization Goals: ✅ No significant changes detected

Fine details of change detection per experiment

Bounds Checks: ✅ Passed

Explanation

CI Pass/Fail Decision

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Static quality checks

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