Computer Performance CS350 Term Project-Spring 2001 Elizabeth Cramer Bryan Driskell Yassaman Shayesteh

What is Computer Performance? One factor in the evaluation of a computer system measured of software and hardware by quantities such as throughput, utilization, and response time.

Why is it Important to Evaluate Computer Performance? Performance is key to the effectiveness of the computer To optimize a general-purpose computing system for a specific installation’s objectives To balance high performance / low cost needs of the manufacturer and the user

History of Computer Performance Original measure of performance- amount of time required to execute a single instruction Second measure of performance- specialized instruction mix Next measure of performance- more developed average instruction execution time

MIPS million instructions per second MIPS = Instruction count execution time * 10^6 MIPS is the measure of instruction execution rate for a particular machine- specifying performance inversely to execution faster machines have a higher MIPS rating

Problems with Using MIPS 1. Unable to compare computers with different instruction sets because the instruction count will differ 2. MIPS varies between programs on same computer- so cannot get a single MIP rating 3. MIPS can vary inversely with performance

MFLOPS million floating-point operations per second MFLOPS = Number of floating point operations in a program Execution time * 10^6 more useful than MIPS because the same program on different machines may vary in number of instructions but will always execute the same number of floating-point operations

Problems with Using MFLOPS 1.Limited to using floating-point arithmetic 2.The set of floating-point operations is not consistent across machines 3.The rating cannot be normalized into a single performance metric

Two Methods of Measuring Performance Users are interested in reducing response time- time between the start and completion of a task Computer managers are interested in increasing throughput- the total amount of work in a given time Therefore- time is the best measurement of performance

CPU Execution Time CPU execution time = (Instruction Count * CPI) / Clock rate Instruction count- the number of instructions executed by the program CPI- clock cycles per instruction Clock rate is the inverse of clock periods

Current Method of Evaluation- Benchmarks A benchmark is a computer program that tests performance Benchmarking means selecting an event or level of performance on a task as the baseline against tasks that will be measured

Application Benchmarks Use running real applications and time how long it takes these applications to execute the specified instructions Give the best measure of how your system performs in the real world Are easy to create

Some Problems With Using Benchmarks Beware of benchmark comparisons- If the peripherals are not identical, the benchmark comparison is meaningless Beware that choosing the highest priced components doesn’t always produce the highest performance

Summarizing & Interpreting Benchmark Tests How retailers use Benchmark software for hardware performance testing Example: Red Hill Technologies– Winstone System Performance Test Use harmonic mean to average “rates of performance”

Intel Performance Results Pentium 4 Processor1.3 GHz 1.4 GHz 1.5 GHz SYSmark 2000 – Win*Me SYSmark 2000 – Win* [Intel Corporation]

Summarizing this data Go to SYSmark’s website to get Rating Methodology, and info on their calibration platform. Compare the calibration platform to the system being rated, they should be similar and standard set-ups

Rating Methodology The application ratings are based on a comparison of workload run times between the system being tested and a fixed calibration platform. A rating of 100 indicates the test system has performance equal to that of the calibration platform, 200 indicates twice the performance of the calibration platform (BAPCo)

Summary Performance evaluation is an important factor in overall computer evaluation for both the manufacturer and the user Time is the most important measure of performance evaluation Benchmark tests are the most common tools used in measuring performance