[CWS] improve memory maps file collection

[paulcacheux]

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What does this PR do?

For some time now we have hit issues with collecting the list of memory mapped files. In https://github.com/DataDog/datadog-agent/pull/17393, we introduced a max amount of collected files, but the call to gopsutil was still parsing the whole smaps file (and returning all stat entries).

This PR is the final challenger to this issue:

• stripped down algorithm, collecting only the paths: no memory used aggregating other entries (especially the ones without path)
• loop stops when we reach the max, actually respecting it which was not the case before
• removes the usage of legacy gopsutil, which is always good

Motivation

Additional Notes

Possible Drawbacks / Trade-offs

Describe how to test/QA your changes

[pr-commenter[bot]]

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=30245165 --os-family=ubuntu

[pr-commenter[bot]]

Regression Detector

Regression Detector Results

Run ID: 99ea77bd-9a8a-42cb-8c2b-a6ed39cda561 Baseline: 93ec749aafca2b8c07d4f3dbebaa1ac8e15233e4 Comparison: 287cfdaa613aae84a1719a220d147fb0764cbd16

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	-0.35	[-6.69, +5.99]

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	+2.40	[-0.37, +5.16]
➖	process_agent_standard_check_with_stats	memory utilization	+0.47	[+0.44, +0.50]
➖	process_agent_real_time_mode	memory utilization	+0.28	[+0.24, +0.31]
➖	idle	memory utilization	+0.25	[+0.22, +0.29]
➖	tcp_syslog_to_blackhole	ingress throughput	+0.23	[+0.14, +0.31]
➖	pycheck_1000_100byte_tags	% cpu utilization	+0.15	[-4.73, +5.03]
➖	otel_to_otel_logs	ingress throughput	+0.09	[-0.34, +0.53]
➖	trace_agent_msgpack	ingress throughput	+0.01	[-0.01, +0.02]
➖	trace_agent_json	ingress throughput	+0.00	[-0.01, +0.01]
➖	uds_dogstatsd_to_api	ingress throughput	-0.00	[-0.20, +0.20]
➖	tcp_dd_logs_filter_exclude	ingress throughput	-0.00	[-0.03, +0.02]
➖	file_to_blackhole	% cpu utilization	-0.35	[-6.69, +5.99]
➖	process_agent_standard_check	memory utilization	-0.37	[-0.41, -0.33]
➖	file_tree	memory utilization	-0.47	[-0.56, -0.37]
➖	basic_py_check	% cpu utilization	-0.52	[-2.86, +1.82]

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".

[agent-platform-auto-pr[bot]]

[Fast Unit Tests Report]

Warning: On pipeline 30245165. The following jobs did not run any unit tests:

• 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-developer-experience

[paulcacheux]

/merge

[dd-devflow[bot]]

:steam_locomotive: MergeQueue

Pull request added to the queue.

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