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Fixed Time Model

Gustavson's Law

• Assumption: available time is constant.
• Goal: solve largest problem in fixed time.
• Strategy: scale workload with processor number.
  • W=W_s+n W_p
  • S_n= W_s+n W_p/W_s+n W_p/n = W_s + n W_p/W_s + W_p = f W + n(1-f)W/fW + (1-f)W = f+n(1-f)
• Speedup grows linearly with n!
• Applies where a "better" solution is appreciated.
  • Refined simulation model.
  • More accurate predictions.

Efficiency remains constant.