Author: Matt Taylor
Date: 23:44:22 02/19/03
Go up one level in this thread
On February 19, 2003 at 16:18:54, Charles Worthington wrote: >On February 19, 2003 at 16:13:58, Steffen Basting wrote: > >>Hi! >>No, I would say Martin is right. You can do that with rather practical numbers: >> >>One processor, ht disabled: 1.000 nps. >>=> Two processors, ht disabled: 2.000 nps. >> >>One processor, ht enabled: 1160 nps (ht disabled + 16%). >>=> Two processors, ht enabled: 2.320 nps. >> >>and 2.000 * 1.16 = 2.320, so your speed up is 16% for both cpus. >> >> >>Regards, Steffen > > >actally the speedup is doubled when you are dealing with dual processors. You >are using reverse mathematics to arrive at an incorrect answer. I honestly think >Dr. Hyatt knows his math. Speedup % does not change neglecting SMP overhead. Enabling HT on one processor means you get a 20-30% speedup. When you take a dual-proc system and enable HT, you also get a 20-30% speedup. The confusion is that Aaron was talking about speed relative to a single CPU. Again neglecting SMP overhead, 1 CPU w/HT is 20-30% faster than 1 CPU. 2 CPUs without HT would be 100% faster than 1 CPU. 2 CPUs with HT would be 140-160% faster than 1 CPU. -Matt
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