O Plameras was once rumoured to have said: > Robert Collins wrote: >> Holy shit! You are soooo off base here its not funny. 'More than one >> thing per clock cycle' -> What do clock cycles have to do with >> parallelism? Nothing. > > Clock cycles has everything to do in the analysis of CPUs. It is the > basic measure of CPU performance.
Wrong. The basic measure of performance is the time required to complete an operation, not the length of a clock cycle. Clock rate and operation speed are very orthogonal things. > In fact you'd be a lot better as a programmer if you do understand > clock cycles. For example, codes expend clock cycles when data are > moved around memory; no clock cycles are expended when data are > moved around certain registers. In this view, you'd learn what > codes in C to avoid and what codes to use. Actuallly, he knows better than you do. 10 years ago, most machines couldn't even fetch data from L1 cache in a single clock cycle -- some of the earier PPCs were a good exception there, but the x86 certainly was not a fast machine when it comes to average cycles per op. (I can't speak for now - nor do I care to - but I'd be amazed if intel has mysteriously revamped their processor to complete all operations in a single cycle though - all of a sudden, all the collected x86 optimisation technique would go to waste). C. -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
