1. COMS 361 Computer Organization
Title: Performance
Date: 9/09/2004
Lecture Number: 5

2. Announcements
Homework 2
Due 9/14/04

3. Review Orders of magnitude Performance The big and small of it
Relationship between
Execution time and clock rate
Execution time and the number of instructions
Instruction and number of clocks

4. Outline
MIPS, MOPS, FLOPS
SPEC Benchmarks

5. MIPS MEASURE Millions of Instructions Per Second
Instruction execution rate
Inverse relationship to the execution time
The higher the MIPS rating the better

6. MIPS MEASURE MIPS Problems
Contains instruction count, not what the instructions do
Small, simple instructions versus large, complex instructions
Cannot compare machines with different ISA’s
Different programs executed on the same computer can have drastically different MIPS rating

7. Exercise 2-15
Compare the MIPS rating of two machines, one with a floating point processor (MFP) and the other without (MNFP)
Clock rate is 1000MHz for each machine
Use a program with this instruction mix
floating-point multiply: 10%
floating-point add: 15%
floating-point divide: 5%
integer instructions: 70%

8. Exercise 2-15 MFP CPI for each instruction class
floating-point multiply: 6
floating-point add: 4
floating-point divide: 20
integer instructions: 2
MNFP emulates floating point with integer instructions
floating-point multiply: 30 integer instructions
floating-point add: 20 integer instructions
floating-point divide: 50 integer instructions

9. Exercise 2-15
Find CPI for MFP

10. Fallacies and Pitfalls
Fallacy
Machine performance increases proportionally to the size of the improvement
Do NOT expect that doubling the clock rate will double the performance!

11. Fallacies and Pitfalls
Amdahl’s law (law of diminishing returns)
Performance enhancements are limited by the amount the enhanced feature is used
Execution Time After Improvement = Execution Time Unaffected (Execution Time Affected / Amount of Improvement )
No sense speeding up instructions that are rarely used
Make the common case fast

12. Benchmarks "A standard of measurement or evaluation"
Standard programs to measure performance
Which programs?
Real applications
Difficult to tailor CPU design to score better
Better designs will likely be better for most applications
Your application!
Performance report
Performance should be repeatable
Include all pertinent information
OS, compilers, flags, number of processors

13. SPEC Benchmarks System Performance Evaluation Corp. (SPEC)
Formed in 1988 by some workstation vendors
There was a desperate need of realistic, standardized performance tests
Fair and useful set of metrics to differentiate candidate systems
Balance between requiring strict compliance and allowing vendors to demonstrate their advantages
An ounce of honest data was (is) worth more than a pound of marketing hype
Ported to a wide variety of platforms of its membership

14. SPEC Benchmarks Now has over 60 member companies
Standardized suite of source code based upon existing applications

15. SPEC Benchmarks The Open Systems Group (OSG) CPU JAVA SDM SFS WEB
CPU benchmarks
JAVA
Java client and server-side benchmarks
SDM
Multi-user UN*X commands benchmarks
SFS
File server benchmarks
WEB
Web server benchmarks

16. SPEC Benchmarks The High-Performance Group (HPG)
High-performance computing applications
Symmetric multiprocessor systems
Workstation clusters
Distributed memory parallel systems
Traditional vector and vector parallel supercomputers

17. SPEC Benchmarks The Graphics Performance Characterization Group (GPC)
SPECapc
Benchmarks for graphics-intensive applications SPEC
SPECopc
OpenGL Performance Characterization determining the performance of the OpenGL application programming interface

18. SPEC CPU2000 Compute intensive performance Processor Memory Compiler
Performance is more than just the processor
CINT2000 compute-intensive integer performance
CFP2000 compute-intensive floating point performance

19. CINT2000 Gzip: Data compression utility
vpr: FPGA circuit placement and routing
gcc: C compiler
mcf : Minimum cost network flow solver
crafty: Chess program
parser Natural language processing
eon: Ray tracing
perlbmk:Perl
gap: Computational group theory
vortex: Object Oriented Database
bzip2 : Data compression utility
twolf: Place and route simulator

20. CFP2000 wupwise: Quantum chromodynamics swim: Shallow water modeling
mgrid: Multi-grid solver in 3D potential field
applu: Parabolic/elliptic partial differential equations
mesa: 3D Graphics library
galgel: Fluid dynamics
art: Neural network simulation
equake: Finite element simulation
facerec Computer vision
ammp: Computational chemistry
lucas: Number theory

21. CFP2000 See for yourself fma3d: Finite element crash simulation
sixtrack: Particle accelerator model
apsi: Temperature, wind, velocity and distribution of pollutants
See for yourself
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