Symbol f
f is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Read this term in its guide →Published equation contexts
Why this formula appears here
Analysis. The following calculation is my own, built to make the MLPerf numbers’ shape explicit rather than to reproduce them exactly. Model checkpoint writes as occurring every T hours, each costing hours of write time, with failures arriving as a Poisson process at fleet-wide rate (failures per hour). For T 1 , a failure inside an interval loses on average T/2 hours of recomputation, so the expected fraction of wall-clock time lost to the combination of checkpoint overhead and lost recompute is approximately . Minimizing over T gives an optimal interval = : the checkpoint interval should shrink as the inverse square…
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Symbol T
T is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Read this term in its guide →Symbol τ
τ occurs above the fraction bar. The numerator is divided by the entire denominator below it.
Read this term in its guide →Symbol λ
λ occurs above the fraction bar. The numerator is divided by the entire denominator below it.
Read this term in its guide →Denominator: 2
The complete quantity below the fraction bar; it must be nonzero for this division.
Read this term in its guide →How to interpret it
With a fixed numerator, increasing a nonzero denominator reduces the fraction. Its accuracy depends on the assumptions and range of use described in the article.
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Published contexts (1)
A symbol can carry a different meaning in another article. Each occurrence keeps its own guide and term definitions.
Equation 12 · Datacenters
AI Datacenter Systems Engineering in 2035: Scenarios, Signals, and Falsifiable Predictions
This equation gives an approximation: it relates the quantities while allowing an approximation.
Analysis. The following calculation is my own, built to make the MLPerf numbers’ shape explicit rather than to reproduce them exactly. Model checkpoint writes as occurring every T hours, each costing hours of write time, with failures arriving as a Poisson process at fleet-wide rate (failures per hour). For T 1 , a failure inside an interval loses on average T/2 hours of recomputation, so the expected fraction of wall-clock time lost to the combination of checkpoint overhead and lost recompute is approximately . Minimizing over T gives an optimal interval = : the checkpoint interval should shrink as the inverse square…
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