Equation 3 · Part 1 · AI Accelerator Architecture in Practice: An Advanced Technical Guide
Symbol P_device
What this part means
a single device’s measured (not advertised) throughput on the actual workload.
Its job in the formula
evice is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Full expression→Symbol P_device→Article meaning
Where the article explains it
where N is the device count, is a single device’s measured (not advertised) throughput on the actual workload, is the utilization fraction observed over a representative multi-hour or multi-day window rather than a benchmark’s best run, and A is availability — the fraction of time the fleet is actually up and assigned to the job rather than down for failure, repair, or checkpoint recovery.
The passage around this formula
where N is the device count, is a single device’s measured (not advertised) throughput on the actual workload, is the utilization fraction observed over a representative multi-hour or multi-day window rather than a benchmark’s best run, and A is availability — the fraction of time the fleet is actually up and assigned to the job rather than down for failure, repair, or checkpoint recovery. Treating A as 1 is the single most common capacity-planning error, and it is the one large-scale operators are most explicit about correcting for.
Learn the underlying idea
A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.
Open the illustrated subscripts: which member of a family? guide →
See this notation across published equations →
Sources cited in the article section
These citations provide research context; check each source for the exact claim it supports.