EnergyEfficiency: Energy and Power

EnergyEfficiency: Energy and Power

1. Computational Efficiency

   • Burstiness
     • System schedules processes needing similar resources
   • Multi-threading
     • Problems
       • One uses more CPU
       • one does work
       • Affinity
     • Data Domain Decomposition (DDC)
     • Imbalanced Threading
       • More time + roughly same power + effort = lost energy
     • Functional Domain Decomposition (FDC)
     • Balanced Threading (BT)
       • Saves time + roughly same power = saved energy
   • Power/performance measurements
     • Always On (AO) Mode
     • Portable Laptop (PL) Mode
   • Performance versus energy
     • Avoid over provisioning
   • Compilers
     • Parallelism
     • Library optimization
     • Instruction set optimization

2. Data Efficiency

   • Networks
     • Compressed vs. uncompressed
       • Compression Ratio
   • Disk I/O
     • Buffer
     • Native Command Queuing
     • Sequential Reads
     • Disk Thrashing
     • File Fragmentation
   • Minimize data movement
     • Caching
     • Algorithms
     • Memory Hierarchy

3. Operating Systems

   • Power Saving Techniques
     • Hibernation
     • Scaling Techniques
       • Dynamic Voltage Scaling
       • Dynamic Frequency Scaling
     • Remote Task Mapping
   • Power Management Policies
     • Maximum Degredation Policy
     • Generalized Energy Delay Policies
   • ECOSystem
     • Cuurentcy Model
       • Energy Allocation
         • 1st Level
           • Time into Energy Epochs
         • Resource Containers
         • 2nd Level
           • Distributes Currentcy
       • Accounting Solutions
       • Managed Devices
         • CPU
         • Disk
         • Network Interface
           • Doze
           • Transmit
           • Receive
   • Device Windows
     • System Device Window
     • Process Device Window

4. Context Awareness

   • Situation/User Driven

5. Compilers

   • Low Level Opimizations
     • Instruction Scheduling
       • Reduce Switching
     • Relabeling Registers
   • High Level Loop Optimizations
     • Linear Loop Transformations
     • Loop Tiling
     • Loop Unrolling

6. Wireless Networks

   • Infrastructure
   • Ad Hoc
   • Protocol Stack
     • Physical Layer
     • Data Link Layer
       • MAC Sublayer
         • IEEE 802.11
           • Channel Sense Multiple Access/Collision Avoidance
           • Extensions
             • Request to Send (RTS)
             • Clear to Send (CTS)
           • Power Conservation Extension
             • Sleep Mode for Nodes
         • EC-MAC Protocol
           • Reduces # of retransmissions
             • Optimized for contiguous time slots
         • PAMAS
       • LLC Sublayer
         • Automatic Repeat Request (ARQ)
           • Probing to Throttle Retranmission
         • Forward Error Correction (FEC)
     • Network Layer
       • Unicast
         • Metrics
           • Time to network partition
           • Variance in power levels across nodes
           • Cost Per Packet
           • Maximum Node Cost
           • Energy consumed per pcket
         • Shortest Cost Routing
           • Know location of all other nodes
       • Broadcast
         • Flooding
         • Broadcast Tree
           • Power Aware Tree
     • Transport Layer
       • TCP
         • Split Connection Protocol
         • Link Layer Protocol
         • End-to-end Protocol
         • Probing
     • OS/Middleware
     • Application Layer
   • Sources of Power Consumption
     • Communication Related
     • Computation Related
   • Conservation Guidelines
     • Avoid Retransmission
     • Receiver constantly on
     • Contiguous Transmission Slots
     • Scheduling Mechanism in Base Station
     • Balance Load
     • Transmit Bandwidth Request