Acceleration

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# Acceleration - PowerPoint PPT Presentation

Acceleration. How to improve speed? At what costs?. T=Nq * CPI * Cycletime. Nq, Number of instructions CPI, Cycles Per Instruction Cycletime. Single Cycle Design. CPI = 1 Cycletime = Long (Longest path). Multiple Cycle. 1 < CPI < S Cycletime = Factor 1/S. Pipelined design.

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## PowerPoint Slideshow about 'Acceleration' - varian

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Presentation Transcript
Acceleration
• How to improve speed?
• At what costs?
T=Nq * CPI * Cycletime
• Nq, Number of instructions
• CPI, Cycles Per Instruction
• Cycletime
Single Cycle Design
• CPI = 1
• Cycletime = Long (Longest path)
Multiple Cycle
• 1 < CPI < S
• Cycletime = Factor 1/S
Pipelined design
• CPI = 1, (Constant)
• Cycletime = Factor 1/S
“THROUGHPUT”
• The total amount of work done in a given time
INSTRUCTION MEMORY STAGE (IM)

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INSTRUCTION

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INSTRUCTION DECODE STAGE (DE)

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INSTRUCTION EXECUTE STAGE (EX)

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DATA MEMORY STAGE (DM)

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DATA MEMORY

WRITEBACK STAGE (WB)

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Pipeline
• 5 stages, (IM, DE, EX, DM, WB)
• Writeback NOT in critical path
• Cut critical path by 4
WRITEBACK STAGE (WB)

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Single Cycle

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Single Cycle

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4 Stage Pipe

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A Program

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4 Stage Pipe

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Step 1

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• 0x38 ori \$2 \$0 0xABCD

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Step 2

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• 0x3C sw \$5 4(\$0)

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Step 4

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• 0x34 add \$7 \$0 \$1

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• 0x38 ori \$2 \$0 0xABCD

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• 0x3C sw \$5 4(\$0)

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Step 5

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• 0x34 add \$7 \$0 \$1

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• 0x38 ori \$2 \$0 0xABCD

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