Software Controlled Power Management Yung-Hsiang Lu Giovanni De - - PowerPoint PPT Presentation
Software Controlled Power Management Yung-Hsiang Lu Giovanni De Micheli Tajana Simunic Computer System Laboratory Stanford University Outline Dynamic Power Management (DPM) ACPI (Advanced Configuration & Power Interface)
Computer System Laboratory Stanford University Yung-Hsiang Lu Tajana Simunic Giovanni De Micheli
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read / write IO complete shut down read / write spin up
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Workload Devices
requests power state commands
Power Manager
parameters request model computers embedded systems portable devices …..
Applications:
Implementation & evaluation Request and device modeling Management algorithms Power and performance tradeoffs
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– allowing dynamic power state change – providing low state-transition overhead
– implementing adaptive, flexible, smart algorithms – using higher-level information
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OS OS
Kernel Kernel Power Management Power Management Device Device Driver Driver ACPI driver ACPI driver AML interpreter AML interpreter
BIOS BIOS Applications Applications Platform Hardware Platform Hardware Motherboard Motherboard devices devices Chipset Chipset CPU CPU ACPI Tables ACPI Tables
ACPI ACPI
Table Table interface interface BIOS BIOS interface interface Register Register interface interface ACPI BIOS ACPI BIOS ACPI registers ACPI registers
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applications hardware devices device-specific driver power manager
requests power manager
ACPI
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applications hardware devices device-specific driver power manager
requests power manager command utilization Experiment DPM Algorithms power manager
ACPI
filter driver
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synchronization creating power command timing analysis
SetPowerState
power state change…. Requests Arrive
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– 3 power states – idle power 3.48 W – sleeping power 0.75 W – 7.2 sec / 52 J to wake up and 0.51 sec to sleep
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read / write IO complete shut down read / write wake up timesleeping × Powersleeping + timeidle × Poweridle + # wakeups × Energywakeup Total Energy =
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1.6 1.8 2 2.2 2.4 30 60 90 120 150 180 Timeout (sec) Power (W)
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1.6 1.8 2 2.2 2.4 30 60 90 120 150 180 Timeout (sec) Power (W)
Adaptive timeout [Lu GLSVLSI 99]: 1.60 W
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30 60 90 120 30 60 90 120 150 180 Timeout (sec) # shutdown
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0% 2% 4% 6% 8% 10% 30 60 90 120 150 180 Timeout (sec) Waiting
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– is portable – facilitates DPM algorithm evaluation – runs realistic workloads
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