usm: sowatcher: Cut instruction cout by 90%

[guyarb]

What does this PR do?

Removes redundant zeroing operations running in a loop. We don't need to zero the buffer as we set the length of the buffer.

Motivation

Cut instruction count by 90%.

Describe how you validated your changes

Possible Drawbacks / Trade-offs

Additional Notes

Diff compared to main

| Filename/Program                                         |   Stack Usage |   Instructions Processed |   Instructions Processed limit |   Max States per Instruction |   Peak States |   Total States |
|----------------------------------------------------------|---------------|--------------------------|--------------------------------|------------------------------|---------------|----------------|
| shared_libraries/tracepoint__syscalls__sys_enter_open    |             0 |                   -17222 |                              0 |                           -4 |           -87 |           -312 |
| shared_libraries/tracepoint__syscalls__sys_enter_openat  |             0 |                   -17222 |                              0 |                           -4 |           -87 |           -312 |
| shared_libraries/tracepoint__syscalls__sys_enter_openat2 |             0 |                   -17222 |                              0 |                           -4 |           -87 |           -312 |
| shared_libraries/tracepoint__syscalls__sys_exit_open     |             0 |                        0 |                              0 |                            0 |             0 |              0 |
| shared_libraries/tracepoint__syscalls__sys_exit_openat   |             0 |                        0 |                              0 |                            0 |             0 |              0 |
| shared_libraries/tracepoint__syscalls__sys_exit_openat2  |             0 |                        0 |                              0 |                            0 |             0 |              0 |

[agent-platform-auto-pr]

[Fast Unit Tests Report]

On pipeline 50673583 (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]

Package size comparison

Comparison with ancestor 5e3a9d7cbe4c2d1f6a1ba917b8d45e1c1448b0a8

Diff per package

package	diff	status	size	ancestor	threshold
datadog-agent-amd64-deb	-0.18MB	✅	1270.68MB	1270.85MB	140.00MB
datadog-iot-agent-amd64-deb	0.00MB	✅	113.20MB	113.20MB	10.00MB
datadog-dogstatsd-amd64-deb	0.00MB	✅	78.32MB	78.32MB	10.00MB
datadog-heroku-agent-amd64-deb	0.00MB	✅	526.45MB	526.45MB	70.00MB
datadog-agent-x86_64-rpm	-0.18MB	✅	1279.91MB	1280.09MB	140.00MB
datadog-agent-x86_64-suse	-0.18MB	✅	1279.91MB	1280.09MB	140.00MB
datadog-iot-agent-x86_64-rpm	0.00MB	✅	113.26MB	113.26MB	10.00MB
datadog-iot-agent-x86_64-suse	0.00MB	✅	113.26MB	113.26MB	10.00MB
datadog-dogstatsd-x86_64-rpm	0.00MB	✅	78.40MB	78.40MB	10.00MB
datadog-dogstatsd-x86_64-suse	0.00MB	✅	78.40MB	78.40MB	10.00MB
datadog-agent-arm64-deb	-0.18MB	✅	1004.85MB	1005.03MB	140.00MB
datadog-iot-agent-arm64-deb	0.00MB	✅	108.67MB	108.67MB	10.00MB
datadog-dogstatsd-arm64-deb	0.00MB	✅	55.59MB	55.59MB	10.00MB
datadog-agent-aarch64-rpm	-0.18MB	✅	1014.06MB	1014.24MB	140.00MB
datadog-iot-agent-aarch64-rpm	0.00MB	✅	108.74MB	108.74MB	10.00MB

Decision

✅ Passed

[agent-platform-auto-pr]

eBPF complexity changes

Summary result: ✅ - stable

• Highest complexity change (%): +0.00%
• Highest complexity change (abs.): +0 instructions
• Programs that were above the 85.0% limit of instructions and are now below: 0
• Programs that were below the 85.0% limit of instructions and are now above: 0

shared_libraries details

shared_libraries [programs with changes]

Program	Avg. complexity	Distro with highest complexity	Distro with lowest complexity
tracepoint__syscalls__sys_enter_openat	🟢 1905.6 (-17183.4, -90.02%)	debian_10/arm64: 🟢 2103.0 (-15921.0, -88.33%)	amazon_5.4/arm64: 🟢 1774.0 (-18025.0, -91.04%)
tracepoint__syscalls__sys_enter_openat2	🟢 1905.6 (-17183.4, -90.02%)	debian_10/arm64: 🟢 2103.0 (-15921.0, -88.33%)	amazon_5.4/arm64: 🟢 1774.0 (-18025.0, -91.04%)

shared_libraries [programs without changes]

Program	Avg. complexity	Distro with highest complexity	Distro with lowest complexity
tracepoint__syscalls__sys_exit_open	⚪ 1577.2 (+0.0, +0.00%)	amazon_5.4/arm64: ⚪ 1796.0 (+0.0, +0.00%)	debian_10/arm64: ⚪ 1249.0 (+0.0, +0.00%)
tracepoint__syscalls__sys_exit_openat	⚪ 1577.2 (+0.0, +0.00%)	amazon_5.4/arm64: ⚪ 1796.0 (+0.0, +0.00%)	debian_10/arm64: ⚪ 1249.0 (+0.0, +0.00%)
tracepoint__syscalls__sys_exit_openat2	⚪ 1577.2 (+0.0, +0.00%)	amazon_5.4/arm64: ⚪ 1796.0 (+0.0, +0.00%)	debian_10/arm64: ⚪ 1249.0 (+0.0, +0.00%)

This report was generated based on the complexity data for the current branch guy.arbitman/sowatcher-cut-inst-count (pipeline 50673583, commit fc21c41) and the base branch main (commit 5e3a9d7). Objects without changes are not reported. Contact #ebpf-platform if you have any questions/feedback.

Table complexity legend: 🔵 - new; ⚪ - unchanged; 🟢 - reduced; 🔴 - increased

[cit-pr-commenter]

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Run ID: bcf74429-51d0-4c26-80ee-496898f29fd5

Baseline: 5e3a9d7
Comparison: fc21c41
Diff

Optimization Goals: ✅ No significant changes detected

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	file_to_blackhole_0ms_latency	egress throughput	+0.17	[-0.63, +0.98]	1	Logs
➖	file_to_blackhole_1000ms_latency_linear_load	egress throughput	+0.16	[-0.32, +0.63]	1	Logs
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	+0.09	[-0.63, +0.81]	1	Logs
➖	file_to_blackhole_100ms_latency	egress throughput	+0.03	[-0.68, +0.75]	1	Logs
➖	file_to_blackhole_300ms_latency	egress throughput	+0.00	[-0.63, +0.64]	1	Logs
➖	file_to_blackhole_0ms_latency_http1	egress throughput	+0.00	[-0.75, +0.76]	1	Logs
➖	uds_dogstatsd_to_api	ingress throughput	+0.00	[-0.09, +0.09]	1	Logs
➖	tcp_dd_logs_filter_exclude	ingress throughput	+0.00	[-0.01, +0.01]	1	Logs
➖	file_to_blackhole_500ms_latency	egress throughput	-0.00	[-0.77, +0.76]	1	Logs
➖	tcp_syslog_to_blackhole	ingress throughput	-0.01	[-0.07, +0.05]	1	Logs
➖	file_to_blackhole_0ms_latency_http2	egress throughput	-0.04	[-0.84, +0.75]	1	Logs
➖	file_to_blackhole_1000ms_latency	egress throughput	-0.05	[-0.84, +0.74]	1	Logs
➖	otel_to_otel_logs	ingress throughput	-0.63	[-1.33, +0.07]	1	Logs
➖	file_tree	memory utilization	-0.70	[-0.82, -0.58]	1	Logs
➖	quality_gate_idle	memory utilization	-0.84	[-0.88, -0.80]	1	Logs bounds checks dashboard
➖	quality_gate_idle_all_features	memory utilization	-1.85	[-1.97, -1.73]	1	Logs bounds checks dashboard
➖	quality_gate_logs	% cpu utilization	-2.94	[-5.90, +0.02]	1	Logs

Bounds Checks: ❌ Failed

perf	experiment	bounds_check_name	replicates_passed	links
❌	file_to_blackhole_500ms_latency	lost_bytes	7/10
❌	file_to_blackhole_0ms_latency	lost_bytes	8/10
✅	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	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, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_logs, 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_idle_all_features, bounds check memory_usage: 10/10 replicas passed. Gate passed.

[guyarb]

/merge

[dd-devflow]

Devflow running: /merge

View all feedbacks in Devflow UI.

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2024-12-10 08:48:46 UTC ℹ️ MergeQueue: pull request added to the queue

The median merge time in main is 24m.