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The Fair Share Scheduler (FSS)
nThe exponentially weighted averages use a
= 1/2:
uCPUj[i] = (1/2)
Uj[i-1] + (1/2) CPUj[i-1]
uGCPUk[i] = (1/2)
GUk[i-1] + (1/2) GCPUk[i-1]
uwhere
FUj[i]
= processor usage by process j in interval i
FGUk[i]
= processor usage by group k in interval i
nRecall that
uPj[i] = Bj + (1/2)
CPUj[i-1] + GCPUk[i-1]/(4Wk)
nThe priority decreases as the process and group use the processor
nWith more weight Wk, group usage decreases less the priority