[windows][wkint-492] Update ETW with new functions; add ability to get ETW stats

[derekwbrown]

intermediate checking. Have standalone commit to allow changing number of ETW buffers

add ability to get etw stats

clean up cherry-pick

What does this PR do?

PR adds two new features to the ETW component for future use (at least) in CWS

1. add ability to specify the number of ETW buffers
2. add ability to query ETW for session statistics (namely dropped notifications)

Describe how to test/QA your changes

This PR is adding the functionality, but there's currently no consumer. Test would be to ensure no loss of functionality in existing consumer(s) (apm) (i.e. regression test).

[pr-commenter]

Test changes on VM

Use this command from test-infra-definitions to manually test this PR changes on a VM:

inv create-vm --pipeline-id=34207644 --os-family=ubuntu

[pr-commenter]

Regression Detector

Regression Detector Results

Run ID: cd0583c0-8c76-424d-87a1-d6812c0be38e
Baseline: 6d305d8
Comparison: 8529db1

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

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	-7.96	[-9.16, -6.77]

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI
➖	tcp_syslog_to_blackhole	ingress throughput	+6.18	[-15.72, +28.07]
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	+1.73	[-1.10, +4.57]
➖	idle	memory utilization	+0.18	[+0.13, +0.22]
➖	trace_agent_json	ingress throughput	+0.00	[-0.01, +0.01]
➖	uds_dogstatsd_to_api	ingress throughput	-0.00	[-0.20, +0.20]
➖	trace_agent_msgpack	ingress throughput	-0.00	[-0.01, +0.01]
➖	tcp_dd_logs_filter_exclude	ingress throughput	-0.01	[-0.05, +0.02]
➖	otel_to_otel_logs	ingress throughput	-0.15	[-0.55, +0.25]
➖	file_tree	memory utilization	-0.24	[-0.34, -0.13]
➖	basic_py_check	% cpu utilization	-0.51	[-2.92, +1.89]
➖	pycheck_1000_100byte_tags	% cpu utilization	-4.46	[-9.13, +0.21]
✅	file_to_blackhole	% cpu utilization	-7.96	[-9.16, -6.77]

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".

[paulcacheux]

it seems from the implementation of NewSession that we could pass nil instead of an empty body function here, but probably just a taste question

[derekwbrown]

true.
It's a derivative of another branch where I had several, unrelated changes for doing the perf testing.

My orig implementation couldn't handle a nil. And, my orig implementation actually filled in something here. But in order to split out into smaller PRs, this PR is only to add the ability to set that config.

[julien-lebot]

I like @paulcacheux suggestion as well, or perhaps providing a default function that does nothing / apply default values:

func DefaultConfig(cfg *etw.SessionConfiguration) {
  //
}
...
etwcomp.NewSession(etwSessionName, etw.DefaultConfig)

It seems to me like it would be a simple change to make.

[derekwbrown]

/merge

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[derekwbrown]

/merge -c

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[derekwbrown]

/merge

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