[dogstatsd] fix replay speed

[d33d33]

trafficstars

What does this PR do?

Change timing logic. Read is now aware of total capture/replay time.

Motivation

dogstatsd-replay is slower than expected, replaying a 10s capture takes 16s.

time agent dogstatsd-replay -f /opt/dsd_capture/prod
Replaying dogstatsd traffic...
clearing agent replay states...
replay done

real	0m16.802s
user	0m0.613s
sys	0m0.446s

Additional Notes

Current logic sleep for inter-message interval and does not keep track of total time (accumulating error over time), leading to slower than capture message replay due to:

• time.Sleep not being nano second accurate
• time.Sleep pauses the current goroutine for at least the duration d

Possible Drawbacks / Trade-offs

dogstatsd-replay produce higher through output.

Describe how to test/QA your changes

Run: time ./bin/agent dogstatsd-replay -c bin/agent/dist/datadog.yaml -f $DSD_CAPTURE

[pr-commenter[bot]]

Bloop Bleep... Dogbot Here

Regression Detector Results

Run ID: 47e05904-525e-4d39-bd73-f85757df989c Baseline: bf655ad8984c6d727bae08cb3feb6d63582e7509 Comparison: 7ca80258442757f4361b9f1928821988a128e5e3 Total CPUs: 7

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	+0.22	[-6.38, +6.81]

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI
➖	process_agent_standard_check	memory utilization	+0.25	[+0.21, +0.29]
➖	file_to_blackhole	% cpu utilization	+0.22	[-6.38, +6.81]
➖	idle	memory utilization	+0.20	[+0.18, +0.23]
➖	process_agent_real_time_mode	memory utilization	+0.08	[+0.05, +0.12]
➖	process_agent_standard_check_with_stats	memory utilization	+0.04	[+0.00, +0.07]
➖	trace_agent_json	ingress throughput	+0.03	[-0.00, +0.06]
➖	tcp_dd_logs_filter_exclude	ingress throughput	+0.00	[-0.00, +0.00]
➖	uds_dogstatsd_to_api	ingress throughput	+0.00	[-0.00, +0.00]
➖	trace_agent_msgpack	ingress throughput	-0.04	[-0.05, -0.02]
➖	tcp_syslog_to_blackhole	ingress throughput	-0.18	[-0.24, -0.13]
➖	file_tree	memory utilization	-0.45	[-0.53, -0.38]
➖	otel_to_otel_logs	ingress throughput	-1.11	[-1.72, -0.50]
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	-1.12	[-2.54, +0.30]

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".

[scottopell]

/merge

[dd-devflow[bot]]

:steam_locomotive: MergeQueue

Pull request added to the queue.

There are 10 builds ahead! (estimated merge in less than 3h)

Use /merge -c to cancel this operation!