fix: exclude final metric sample when running with workload #570
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When collecting metrics with a workload (e.g., `perfspect metrics -- stress-ng`), the final sample may be collected after or during workload completion, capturing system transition from loaded to idle state. With short collections, this single anomalous sample can significantly skew summary statistics (mean, min, max, stddev). This change automatically excludes the final timestamp's samples from summary statistics when metrics are collected with a workload. The full CSV with all samples is still preserved for advanced analysis. Implementation: - Added `WithWorkload` field to `Metadata` struct to track workload context - Set `WithWorkload = true` when workload application arguments are provided - Added `excludeFinalSample()` method to remove final timestamp rows before computing summary statistics - Optimized to check first group only and log once per collection Fixes #569 Signed-off-by: Harper, Jason M <jason.m.harper@intel.com>
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Summary
Fixes #569 - Prevents skewed mean metric values when collecting metrics for workloads.
When collecting metrics with a workload (e.g.,
perfspect metrics -- stress-ng --cpu 0 --cpu-load 60 --timeout 30), the final sample may be collected after or during workload completion. This captures the system transitioning from loaded to idle state. With short collections (e.g., 30 seconds = 6 samples), this single anomalous sample can significantly skew summary statistics.Changes
WithWorkloadfield toMetadatastruct - Tracks whether metrics were collected with a user-provided workload applicationWithWorkload = truewhen workload arguments are provided via--excludeFinalSample()method - Removes final timestamp's rows from all metric groups before computing summary statisticsSolution Approach
The implementation excludes the final timestamp's samples from summary statistics when
metadata.WithWorkloadis true. The full CSV with all samples is still preserved for users who want to perform advanced analysis.Testing
make checkpasses (format, vet, staticcheck, lint, vulnerabilities, tests)Test plan
perfspect metrics -- stress-ng --cpu 0 --cpu-load 60 --timeout 30