Transcript Dynamic power management for embedded system

Technical Seminar Presentation 2004
Dynamic power management for embedded system
“Dynamic power management for embedded
system”
Under the guidance of
Mr. Shyamalendu Mohanty
Presented by- Geetanjali Konhar
EE 200167O81
1
Technical Seminar Presentation 2004
Dynamic power management for embedded system
Introduction
 This dynamic power management refers to power
management schemes implemented while programs
are running.
 This architecture is based on the capabilities of
current and next-generation processors and their
application requirements.
Presented by- Geetanjali Konhar
EE 200167O81
2
Technical Seminar Presentation 2004
Dynamic power management for embedded system
REQUIREMENTS
 The overriding power management goal in portable
system is to reduce system-wide energy consumption.
Dynamic power management is only concerned with
voltage and frequency.
Dynamic power management architecture supports the
ability of processors and external bus frequencies, in
concerned with or even independent of the CPU
frequency.
Presented by- Geetanjali Konhar
EE 200167O81
3
Technical Seminar Presentation 2004
Dynamic power management for embedded system
ARCHITECTURAL OVER VIEW
A high-level view of dynamic power management
Presented by- Geetanjali Konhar
EE 200167O81
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Technical Seminar Presentation 2004
Dynamic power management for embedded system
 The low-level implementation of the dynamic power
management architecture (DPM) is resident in the
kernel of the operating system.
 DPM is not a self-contained device driver.
 Complete power management strategy is
communicated to DPM in to ways: as an predefined
set of policies and as an application/policy-set specific
manager that manages them.
Presented by- Geetanjali Konhar
EE 200167O81
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Technical Seminar Presentation 2004
Dynamic power management for embedded system
 Policies specify the component and device-state
transitions that ensure reliable operation in line with the
power management strategy.
 DPM policy managers are executable programs that
activate policies by name.
 Policy managers implement user defined and/or
application-specific power management strategies. They
can execute either as part of the kernel or in user space
(or both) as required by the strategy.
Presented by- Geetanjali Konhar
EE 200167O81
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Technical Seminar Presentation 2004
Dynamic power management for embedded system
POLICY ARCHITECTURE
 OPERATING POINTS
 Operating point may be described different
parameters such as core voltage, CPU bus
frequencies and states of peripheral devices.
 Operating points for the IBM PowerPC 405LP
specify a core voltage level, CPU and bus
frequencies, memory timing parameters and other
clocking related data.
Presented by- Geetanjali Konhar
EE 200167O81
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Technical Seminar Presentation 2004
Dynamic power management for embedded system
OPERATING STATES
In dynamic power management policy, operating
state associated with an operating point specific to
the requirements of that state.
Operating state was the observation that includes
the system-wide energy savings, it can be done by
reducing CPU and bus frequency and core voltage
while the system is in ideal state.
Presented by- Geetanjali Konhar
EE 200167O81
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Dynamic power management for embedded system
Technical Seminar Presentation 2004
POLICIES AND POLICY MANAGER
Policy maps each operating state to a congruence
class of operating point.
 Policy manager collect information from the
operating system, user performances, running
programs, configuration files and/or physical devices
to make it policy decisions.
Presented by- Geetanjali Konhar
EE 200167O81
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Technical Seminar Presentation 2004
Dynamic power management for embedded system
DEVICE CONSTRAINT MANAGER
Automatic selection of operating points as devices
change states is a central feature of DPM.
Embedded systems may not have a BIOS or machine
abstraction layer to insulate the operating system from
low-level device and power management.
The most aggressive power management strategies will
also require the system designer to carefully consider the
influence of attached devices on the strategy.
Presented by- Geetanjali Konhar
EE 200167O81
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Technical Seminar Presentation 2004
Dynamic power management for embedded system
ABSTRACT IMPLIMENTATION
This Section gives our preferred implementation and
the rationale behind the choices made in the
implementation.
Two of the challenges with respect to implementing
this system include:
Changes in device constraints may invalidate
operating points. Automating these transitions is the
primary mechanism by which the architecture
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EE 200167O81
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Technical Seminar Presentation 2004
Dynamic power management for embedded system
relieves the high-level power management task from
having to deal with device states. This leads to several
conflicts.
 Operations on the DPM implementation may block.
Blocking could arise at the very lowest level of the
implementation, where power management device
drivers use system I/O ports to control voltages and
frequencies.
Presented by- Geetanjali Konhar
EE 200167O81
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Technical Seminar Presentation 2004
Dynamic power management for embedded system
Implementation and Effects Of task_specific
Operating States
 task-specific operating points,implemented by
assigning different task operating states to different tasks.
The task state of a task is changed by the set_task_state
() entry point, which may be exported to the user level as
a system call.
Thus a system can be constructed where a single
intelligent policy manager controlled the task states of
critical programs for improved power/performance
efficiency.
Presented by- Geetanjali Konhar
EE 200167O81
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Technical Seminar Presentation 2004
Dynamic power management for embedded system
CONCLUSION
This paper has proposed an architecture supporting
aggressive dynamic power management for embedded
systems. The power management schemes implemented
while programs are running. Dynamic power management
strategies based on dynamic voltage and frequency
scaling.
Presented by- Geetanjali Konhar
EE 200167O81
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Technical Seminar Presentation 2004
Dynamic power management for embedded system
THANK YOU
Presented by- Geetanjali Konhar
EE 200167O81
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