Label the perf image per variant

[epompeii]

The perf image catches up with the perf query.

The parameter

The image endpoint takes parameters, the same comma separated list of URL encoded parameter sets the query endpoint takes, spelled the same way and read by the same code path. The image query struct mirrors the query struct field for field, doc comment included, so the image is the plot of the query it mirrors. An endpoint test pins that: the image of a filtered query is byte for byte the plot of that query's own response.

The label rules

A line plots one variant, so the key names the variant when the benchmark name no longer says which line is which.

• A benchmark whose every line in the image plots the empty parameter set keeps the bare benchmark name it has always had.
• One non empty set among a benchmark's lines names them all. Each line's benchmark row becomes the benchmark name, a space, and the set in its canonical form, so the empty set among them reads {}.
• The set follows the benchmark name on the same row, so the wrapping and font shrinking the key text already does for a long benchmark name loses the tail of the set spelling first and the benchmark name never.

What older projects see

A project that never reported a parameter set is drawn from the inputs it was always drawn from. Every line of every such benchmark is labeled exactly as before, which the existing fixtures pin line by line, and nothing else on the draw path moved.

Points with no value

A point whose measure named no value has no point estimate to place on the axis, so the plot leaves it out of the line rather than drawing it at zero. That already held; a fixture now pins it.

[github-actions]

Bencher Report

Project	Bencher
Branch	u/ep/parameters-api/perf-img
Testbed	intel-v1

Click to view all benchmark results

Benchmark	Latency	Benchmark Result microseconds (µs) (Result Δ%)	Upper Boundary microseconds (µs) (Limit %)
Adapter::Json	📈 view plot 🚷 view threshold	5.22 µs (+10.09%) Baseline: 4.74 µs	5.47 µs (95.45%)
Adapter::Magic (JSON)	📈 view plot 🚷 view threshold	5.02 µs (+9.10%) Baseline: 4.60 µs	5.25 µs (95.57%)
Adapter::Magic (Rust)	📈 view plot 🚷 view threshold	26.98 µs (+3.75%) Baseline: 26.01 µs	27.93 µs (96.61%)
Adapter::Rust	📈 view plot 🚷 view threshold	4.62 µs (+26.45%) Baseline: 3.65 µs	5.11 µs (90.40%)
Adapter::RustBench	📈 view plot 🚷 view threshold	4.64 µs (+27.21%) Baseline: 3.65 µs	5.09 µs (91.09%)

🐰 View full continuous benchmarking report in Bencher