[CWS] send a custom event on hello message

[safchain]

What does this PR do?

Send a custom event when a ptracer is sending a hello message so that we can track if the ptracer is connected

Motivation

Additional Notes

Possible Drawbacks / Trade-offs

Describe how to test/QA your changes

[pr-commenter[bot]]

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Regression Detector Results

Run ID: 0701b3ac-522c-46b8-ad48-7a73c5c86e36 Baseline: c08e2d1a3ca323b1234ba1d29e6deca79c9eac4e Comparison: 4ee372e5591596e72ef6cfb0ee31a26e2cc6867a

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

Experiments with missing or malformed data

• basic_py_check

Usually, this warning means that there is no usable optimization goal data for that experiment, which could be a result of misconfiguration.

No significant changes in experiment optimization goals

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

There were no significant changes in experiment optimization goals at this confidence level and effect size tolerance.

Experiments ignored for regressions

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

perf	experiment	goal	Δ mean %	Δ mean % CI
➖	file_to_blackhole	% cpu utilization	+0.34	[-6.25, +6.92]

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI
➖	process_agent_real_time_mode	memory utilization	+0.76	[+0.73, +0.80]
➖	idle	memory utilization	+0.35	[+0.32, +0.38]
➖	file_to_blackhole	% cpu utilization	+0.34	[-6.25, +6.92]
➖	process_agent_standard_check_with_stats	memory utilization	+0.02	[-0.03, +0.07]
➖	uds_dogstatsd_to_api	ingress throughput	+0.00	[-0.00, +0.00]
➖	tcp_dd_logs_filter_exclude	ingress throughput	-0.00	[-0.00, +0.00]
➖	trace_agent_msgpack	ingress throughput	-0.01	[-0.02, +0.00]
➖	trace_agent_json	ingress throughput	-0.02	[-0.06, +0.03]
➖	process_agent_standard_check	memory utilization	-0.24	[-0.28, -0.20]
➖	file_tree	memory utilization	-0.50	[-0.61, -0.39]
➖	tcp_syslog_to_blackhole	ingress throughput	-0.64	[-0.69, -0.59]
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	-0.70	[-2.13, +0.72]
➖	otel_to_otel_logs	ingress throughput	-1.19	[-1.83, -0.55]

Explanation

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".

[safchain]

/merge

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