Roofline attainable-performance bound

Bounds attainable kernel performance by whichever ceiling is lower: compute throughput or data-movement throughput.

Attainable performance equals the minimum of peak compute performance and memory bandwidth times arithmetic intensity.

A kernel runs no faster than its compute hardware or its ability to feed data, whichever limit is reached first.

Minimum is the main verb: performance is capped by the lower of two independently calculated roofs.

The Roofline model is an upper-bound diagnostic, not a latency prediction; overheads and imperfect utilization can place real performance below the roof.