Книга: Introduction to Microprocessors and Microcontrollers

FLOPS (FLoating-point Operations Per Second)

To overcome the problem of which instructions should be employed some standard floating-point operations can be used.

As a quick reminder, a floating point number is one in which we have moved the decimal point to the start of the number, so 123.456 would be converted to 1.23456?10?. This makes the mathematics faster. Modern microprocessors would have values in the order of ten GFLOPS (GigaFLOPS).

This also meets with objections. The obvious question is, ‘What “operation” is being measured?’ Choose your operation carefully and the opposition is left far behind.

Both of these tests, MIPS and FLOPS are supposed to be microprocessor tests and not system tests.

System tests

Other speed measurements tend to be system tests rather than microprocessor tests but a brief overview may be in order since they are often quoted, almost as alternatives.

Benchmarks

These tests are based on making the microprocessor-based system run a standard or ‘benchmark’ program. The immediate failing here is that to get a program to run on microprocessors with incompatible code will mean that the compilers will also be tested, which is not part of the system. There is also an immediate outcry from people who disagree with the program chosen since it doesn’t suit their system.

I/O operations (input/output operations)

As the name suggests, this measures the speed of accepting information in and sending it out again. But loading information from a CD for example will depend on whether the information is being read from the same track or does the head have to move and include seektime?

TPS (Transactions Per Second)

This is a move to model the tasks set into real-life situations. It requires the system to take in information, modify it and then store it again. It puts a heavy significance on memory access times and compilers.

SPECmark (Systems Performance Evaluation Co-operative’s benchmark)

This is the average result of carrying out 10 agreed benchmark tests in an attempt to measure the system performance in a range of situations. Recent changes include one using floating point arithmetic, which is of more interest to serious number crunching in science and engineering and the other an integer test for the rest of us. These are referred to as SPECfp95 and SPECint95. As a starting point for comparison, the 200 MHz Intel Pentium Pro delivers a value of 8.71 using the SPECint95.

Оглавление книги