Provide three-state output: "changed", "not changed", "unsure"

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Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
35/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
rust

Research direction

The issue names no files, tests, or entry points. Start by locating the Behrens-Fisher confidence classification and the benchmark result output, then determine how insufficient precision should be represented and tested. Done means Sightglass can distinguish changed, not changed, and unsure outcomes at the requested confidence.

Written by the indexing model from the issue text.

Description

Right now, Sightglass uses a single threshold based on a confidence interval computed by Behrens-Fisher to determine whether a sampled statistic shifted between configurations.

The result of this is that we get either "changed" (i.e., benchmark got 5% faster) or "not changed". However, the latter answer can also appear if we simply don't have enough data points to prove statistical significance, or if the system is too noisy.

This "false negative" is somewhat dangerous: we could make a change, see that it is performance-neutral according to Sightglass, and accept it, but actually we just didn't turn the knobs up high enough.

Ideally, Sightglass should provide a third output of "unsure" if the measurements aren't precise enough to prove either "changed" or "not changed" to the desired confidence.

Dominant language
WebAssembly
Stars
88
Forks
37
Avg merge
5h 5m
Merged PRs (30d)
1

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