System Performance Tuning, 2nd Edition

Chapter 3. Processors

Quote performance in terms of processor utilization, parallel speed-ups, or MFLOPS per dollar.

—D. H. Bailey, “Twelve ways to fool the masses when giving performance results on parallel supercomputers.” Supercomputing Review, 1991

The increase in microprocessor performance over the last 20 years has been phenomenal. The prediction made by Gordon Moore, the founder of Intel, that transistor counts on microprocessors would double every 18 months (and thus performance would increase proportionately), has certainly held true, if not been exceeded. In the early 1980s, the fastest microprocessor from Intel was the 4004, which was clocked at less than 4 KHz; by comparison, in mid-2001, the latest generations of IA-32 processors from Intel and AMD are running at clock rates of about 2.0 GHz -- and execute more than one instruction per clock cycle (I survey some the key elements in microprocessor design later in this chapter). This jump is so huge that it is hard to comprehend. If automobile performance followed the same growth curve as microprocessors over the last 20 years, the successor to the DeLorean DMC-12 (1981-1983), which had a top speed of perhaps 140 miles per hour,^[1] would have doubled 12 times: it would travel at almost 287 thousand miles per hour, which is equivalent to about 410 times the speed of sound, or about one-sixteenth of the speed of light. Even that’s pretty difficult to comprehend. If a pack of bubble gum cost a quarter in 1983, and prices ...