Lower is betterThe vertical axis is time per operation (or bytes, where labelled). Every chart is a cost. A line going down is an improvement; a line going up is a regression.
One point, one commitLeft is older, right is newer. Hover a point for the commit message and the exact value; click it to open the commit on GitHub.
The band is the spreadThe shaded band is the run's own spread: for the real-corpus rows the distance from the median to the 95th percentile, for the Criterion rows the deviation it reports. Compare the lines, not the edges of the bands.
Machines varyRunners are shared virtual machines. A step on every chart at the same commit is a different runner, not the code. A step on one chart is the code.