Problem 1 (30 points): Suppose we have two versions of a MIPS pipeline.

Version 1: this is the 5-stage pipeline discussed in Chapter 4 up to Slide 73 or so. Taken branches take one stall, non-taken branches do not stall. Cycle time is 400 ps.

Version 2: this is an 8-stage pipeline, similar to the one discussed in Chapter 4 Slides 93- 94, but with 3 stages for MEM instead of two:

IF1IF2ID EX ME1ME2ME3WB

Cycle time is 250 ps. Refer to the discussion in class for the number of cycles for a load- use stall, and for the number of stalls taken by each type of branch.

We run the program Spectre on the two versions of the MIPS pipeline. Instruction mix:

Loads 35% Stores 10% ALU 35% Branches 20%

55% of the loads incur load-use stalls; the number of cycles for each load-use stall depends on the version of the pipeline only. 65% of all branches are taken.

Let the instruction count of Spectre be IC. What is the total execution time of Spectre on each version of the pipeline? Make sure you show work and specify units clearly.

Problem 1 (30 points): Suppose we have two versions of a MIPS pipeline. Version 1: this is the 5-stage pipeline discussed in Chapter 4 up to Slide 73 or so. Taken branches take one stall, non-taken branches do not stall. Cycle time is 400 ps Version 2: this is an 8-stage pipeline, similar to the one discussed in Chapter 4 Slides 93- 94, but with 3 stages for MEM instead of two: IF1 IF2 ID EX ME1 ME2 ME3 WB Cycle time is 250 ps. Refer to the discussion in class for the number of cycles for a load- use stall, and for the number of stalls taken by each type of branch. We run the program Spectre on the two versions of the MIPS pipeline. Instruction mix: Loads Stores ALU Branches 35% 10% 35% 20% 55% of the loads incur load-use stalls, the number of cycles for each load-use stall depends on the version of the pipeline only, 65% of all branches are taken. Let the instruction count of Spectre be IC. What is the total execution time of Spectre on each version of the pipeline? Make sure you show work and specify units clearly Problem 1 (30 points): Suppose we have two versions of a MIPS pipeline. Version 1: this is the 5-stage pipeline discussed in Chapter 4 up to Slide 73 or so. Taken branches take one stall, non-taken branches do not stall. Cycle time is 400 ps Version 2: this is an 8-stage pipeline, similar to the one discussed in Chapter 4 Slides 93- 94, but with 3 stages for MEM instead of two: IF1 IF2 ID EX ME1 ME2 ME3 WB Cycle time is 250 ps. Refer to the discussion in class for the number of cycles for a load- use stall, and for the number of stalls taken by each type of branch. We run the program Spectre on the two versions of the MIPS pipeline. Instruction mix: Loads Stores ALU Branches 35% 10% 35% 20% 55% of the loads incur load-use stalls, the number of cycles for each load-use stall depends on the version of the pipeline only, 65% of all branches are taken. Let the instruction count of Spectre be IC. What is the total execution time of Spectre on each version of the pipeline? Make sure you show work and specify units clearly