Vinay Devadas Hakan AydinProfessor : Chen, Ya-ShuPresenter : Ho, Shu-Wei

OutlineBreak-even time(B)Next Device Usage Time(NDUT(t))Conservative Energy-Efficient Device

Scheduling(CEEDS)Device Forbidden Region(DFR)FeasibilityDynamic Power Management(DPM) through

Device Forbidden RegionsComparisonConclusion

Break-even time

: The power consumption in active state : The power consumption in sleep state : The time overhead to perform a transition from active to sleep state : The time overhead to perform a transition from sleep to active state : The energy overhead to perform a transition from active to sleep state : The energy overhead to perform a transition from sleep to active state : The break-even time of the device

iaPisPiastisatiasEisaE

iB

[ ( )]max{ , }

i i i i ii i as sa s as sa

i as sa i ia s

E E P t tB t t

P P

Next Device Usage Time(NDUT(t))PredictionCurrent time(t)Tasks in ready queueRelease time of jobs that request

Current t NDUT(t)

Task use iD

iD

( )NDUT t t B

Conservative Energy-Efficient Device Scheduling

Predicting NDUT(t)Example : = = 1000 = = 4000 = 990 , = = 495 = 20 , = = 10 T1 : (2000, 1000) ; T2 : (4000, 1000)

1 2

12

1B

2B

1ast

1sat

2ast

2sat

Conservative Energy-Efficient Device Scheduling

1000

2000

3000

4000

5000

6000

7000

Active

Active

Sleep

Sleep

1D

2D

0

1495 1505 3495 3505 5495 5505

2010 3990 6010

1T

2T

Device Forbidden Region(DFR)Rat-Monotonic scheduling(RMS).Duration

Period

Expected Energy Savings(EES) of

( )i ii ii a s

i

BEES P P

( )NDUT t t B i

i

iD

min( )i i

i i j jB T C

max{ }1 i i

i

ii j

D

TU

FeasibilityTime demand function of

Corollary :A set of periodic tasks can be feasibly

scheduledby DFR-RMS if ∀ i ∃ t 0 ≤ t ≤ Ti,

( )

( )i

i i jhp i j

tw t C C

T

max

( )

( ) ( )i

i i

FRi i j j

hp i j DULj j

t tw t w t C C

T

i

max ( )iw t t

DPM through Device Forbidden Regions

1000

4000

5000

6000

Active

Active

Sleep

Sleep

1D

2D

0

1495 2505 5495 5505

2010 6010

1T

2T3000

2000

10 990 4990

2000

7000

1FR 1FR

2FR 2FR

ComparisonAlways on (AON) --Where the devices remain in active state throughout the simulation (no dynamic power

management).

CEEDS --Adapted to RMS settings. This scheme performs device

shutdown and activation based solely on next device usage time predictions.

DER-RMS

Comparison

mod vari i i i i idevice fixed trans fixedE E E E E E

Conclusion

Compare with original CEES, no matter with DVS or without DVS, RMS-DFR can save up to 27% energy consumption , under the worst condition, it can also save 20% consumption.