Function take_samples 

pub(crate) fn take_samples(
    program: &Arc<Program>,
    sources: &Arc<SourceMap>,
    rows: &mut [Row<'_>],
    iterations: u32,
    order: SampleOrder,
)

Fills every row’s series, in the order order asks for.

Both orders run exactly the same runs exactly as many times. What differs is when: SampleOrder::Blocked finishes a row before it starts the next one, so a row’s whole series is taken in one span of the suite, and SampleOrder::RoundRobin takes one sample of every row per pass, so each row’s series is spread across the whole of it.