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The Fair Share Scheduler (FSS)
nHas been implemented on some Unix OS
nProcesses are divided into groups
nGroup k has a fraction Wk of the CPU
nThe priority Pj[i]
of process j (belonging to group k) at time
interval i is given by:
uPj[i] = Bj + (1/2) CPUj[i-1] + GCPUk[i-1]/(4Wk)
FA high value means a low
priority
FProcess with highest
priority is executed next
FBj = base priority of
process j
FCPUj[i] = Exponentially
weighted average of processor usage by process j in time interval i
FGCPUk[i] = Exponentially
weighted average processor usage by group k in time interval i