On Tue, 4 Feb 2014 10:10:39 -0600, Mike Schwab wrote: >I think a table of the shortest possible execution times for an >instruction would be useful, how many operands it uses, and at the end >a list of how much longer a fetch takes if an operand is not stored in >the fastest level of cache.
John Eels had a SHARE presentation a couple of years ago where he described the cost of going to memory. See page 88 of this: https://share.confex.com/share/119/webprogramschedule/Handout/Session11718/SHARE 119 Session 11718 Presentation.pdf I don't remember what processor this information referred to. Bottom line is that when the data comes from L1 cache, it is available during the same machine cycle. If it has to come from main storage, it takes about 850 machine cycles. -- Tom Marchant ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
