[Backport 7.59.x] expand conn_close_flushed map and add telemetry

[agent-platform-auto-pr]

Backport abc808b from #30586.

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What does this PR do?

Increases the size of the conn_close_flushed map which is filling up in some cases in production. Adds some telemetry to give us more insight into this issue.

Motivation

Describe how to test/QA your changes

Possible Drawbacks / Trade-offs

Additional Notes

[agent-platform-auto-pr]

[Fast Unit Tests Report]

On pipeline 47772981 (CI Visibility). The following jobs did not run any unit tests:

Jobs:

• tests_deb-arm64-py3
• tests_deb-x64-py3
• tests_flavor_dogstatsd_deb-x64
• tests_flavor_heroku_deb-x64
• tests_flavor_iot_deb-x64
• tests_rpm-arm64-py3
• tests_rpm-x64-py3
• tests_windows-x64

If you modified Go files and expected unit tests to run in these jobs, please double check the job logs. If you think tests should have been executed reach out to #agent-devx-help

[agent-platform-auto-pr]

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=47772981 --os-family=ubuntu

Note: This applies to commit 56388f1

[cit-pr-commenter]

Regression Detector

Regression Detector Results

Run ID: 9a1cf968-7135-4ba1-b3b3-cf1dd65cc08f Metrics dashboard Target profiles

Baseline: 96f2ee1
Comparison: 56388f1

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.

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	+1.16	[+0.43, +1.89]	1	Logs
➖	pycheck_lots_of_tags	% cpu utilization	+0.76	[-1.70, +3.22]	1	Logs
➖	idle_all_features	memory utilization	+0.61	[+0.52, +0.71]	1	Logs
➖	basic_py_check	% cpu utilization	+0.30	[-2.43, +3.02]	1	Logs
➖	tcp_dd_logs_filter_exclude	ingress throughput	+0.00	[-0.01, +0.01]	1	Logs
➖	idle	memory utilization	-0.01	[-0.06, +0.04]	1	Logs
➖	uds_dogstatsd_to_api	ingress throughput	-0.01	[-0.11, +0.09]	1	Logs
➖	otel_to_otel_logs	ingress throughput	-0.07	[-0.88, +0.73]	1	Logs
➖	file_tree	memory utilization	-0.15	[-0.26, -0.04]	1	Logs
➖	tcp_syslog_to_blackhole	ingress throughput	-0.88	[-0.93, -0.82]	1	Logs

Bounds Checks

perf	experiment	bounds_check_name	replicates_passed
✅	idle	memory_usage	10/10

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".