[CWS] derive argument count in fexit hooks from BTF data

[paulcacheux]

What does this PR do?

This PR allows, through some BTF hackery, to directly say CTX_PARMRET(ctx) instead of the current CTX_PARMRET(ctx, argc).
Argc was required because on fexit hooks we need to have the amount of arguments the hooked function takes. This PR uses BTF to derive this value, allowing to remove the need for explicitly passing it. This is useful because it allows to be more resilient against function signature changes, and removes some magic constants as well.

Motivation

Describe how you validated your changes

Possible Drawbacks / Trade-offs

Additional Notes

[cit-pr-commenter]

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Run ID: 8295e089-8374-46ca-bd31-6f0cd37bc45c

Baseline: 1af8863
Comparison: 30d6ee7
Diff

Optimization Goals: ✅ No significant changes detected

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	tcp_syslog_to_blackhole	ingress throughput	+1.39	[+1.34, +1.45]	1	Logs
➖	quality_gate_logs	% cpu utilization	+1.20	[-2.12, +4.53]	1	Logs
➖	quality_gate_idle	memory utilization	+0.66	[+0.62, +0.69]	1	Logs bounds checks dashboard
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	+0.29	[-0.39, +0.97]	1	Logs
➖	quality_gate_idle_all_features	memory utilization	+0.20	[+0.12, +0.29]	1	Logs bounds checks dashboard
➖	file_to_blackhole_500ms_latency	egress throughput	+0.04	[-0.74, +0.82]	1	Logs
➖	file_to_blackhole_0ms_latency_http1	egress throughput	+0.03	[-0.83, +0.89]	1	Logs
➖	file_to_blackhole_300ms_latency	egress throughput	+0.02	[-0.63, +0.66]	1	Logs
➖	file_to_blackhole_100ms_latency	egress throughput	+0.01	[-0.71, +0.72]	1	Logs
➖	uds_dogstatsd_to_api	ingress throughput	+0.01	[-0.10, +0.11]	1	Logs
➖	tcp_dd_logs_filter_exclude	ingress throughput	-0.00	[-0.01, +0.01]	1	Logs
➖	file_to_blackhole_0ms_latency	egress throughput	-0.01	[-0.91, +0.88]	1	Logs
➖	file_to_blackhole_0ms_latency_http2	egress throughput	-0.02	[-0.87, +0.82]	1	Logs
➖	file_tree	memory utilization	-0.15	[-0.28, -0.01]	1	Logs
➖	file_to_blackhole_1000ms_latency_linear_load	egress throughput	-0.20	[-0.67, +0.26]	1	Logs
➖	file_to_blackhole_1000ms_latency	egress throughput	-0.23	[-1.03, +0.56]	1	Logs

Bounds Checks: ✅ Passed

perf	experiment	bounds_check_name	replicates_passed	links
✅	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	memory_usage	10/10	bounds checks dashboard
✅	quality_gate_idle_all_features	memory_usage	10/10	bounds checks dashboard
✅	quality_gate_logs	lost_bytes	10/10
✅	quality_gate_logs	memory_usage	10/10

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:

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".

CI Pass/Fail Decision

✅ Passed. All Quality Gates passed.

• quality_gate_idle_all_features, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle, 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.

[agent-platform-auto-pr]

Uncompressed package size comparison

Comparison with ancestor 1af8863cd8cd775bae45659422a477d619468336

Diff per package

package	diff	status	size	ancestor	threshold
datadog-agent-arm64-deb	0.21MB	⚠️	940.50MB	940.29MB	140.00MB
datadog-agent-aarch64-rpm	0.21MB	⚠️	949.79MB	949.59MB	140.00MB
datadog-agent-amd64-deb	0.20MB	⚠️	1198.11MB	1197.92MB	140.00MB
datadog-agent-x86_64-rpm	0.20MB	⚠️	1207.43MB	1207.23MB	140.00MB
datadog-agent-x86_64-suse	0.20MB	⚠️	1207.43MB	1207.23MB	140.00MB
datadog-dogstatsd-amd64-deb	0.00MB	✅	79.00MB	79.00MB	10.00MB
datadog-dogstatsd-x86_64-rpm	0.00MB	✅	79.08MB	79.08MB	10.00MB
datadog-dogstatsd-x86_64-suse	0.00MB	✅	79.08MB	79.08MB	10.00MB
datadog-dogstatsd-arm64-deb	0.00MB	✅	56.10MB	56.10MB	10.00MB
datadog-heroku-agent-amd64-deb	0.00MB	✅	506.09MB	506.09MB	70.00MB
datadog-iot-agent-amd64-deb	0.00MB	✅	113.76MB	113.76MB	10.00MB
datadog-iot-agent-x86_64-rpm	0.00MB	✅	113.83MB	113.83MB	10.00MB
datadog-iot-agent-x86_64-suse	0.00MB	✅	113.83MB	113.83MB	10.00MB
datadog-iot-agent-arm64-deb	0.00MB	✅	109.21MB	109.21MB	10.00MB
datadog-iot-agent-aarch64-rpm	0.00MB	✅	109.28MB	109.28MB	10.00MB

Decision

⚠️ Warning

[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 aws.create-vm --pipeline-id=52081554 --os-family=ubuntu

Note: This applies to commit 30d6ee7

[paulcacheux]

/merge

[dd-devflow]

Devflow running: /merge

View all feedbacks in Devflow UI.

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2025-01-03 11:42:46 UTC ℹ️ MergeQueue: pull request added to the queue

The median merge time in main is 35m.

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2025-01-03 12:16:55 UTC ℹ️ MergeQueue: This merge request was merged