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How do I know which machine is faster ?
Machine A:
Fclk = 2.4Ghz; CPI = 2.5
Machine B:
Fclk = 1.8Ghz; CPI = 2.0
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#2
Posted 25 April 2011 - 07:43 AM
gregwarner
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You want to know how many instructions per second each CPU can perform. To get this, divide the Cycles per Second (the speed) by the Cycles per Instruction. The Cycle terms cancel out, yielding Instructions per Second. The CPU with the larger value will be faster.
Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law.
– Douglas Hofstadter, Gödel, Escher, Bach: An Eternal Golden Braid
#3
Posted 25 April 2011 - 07:48 AM
gregwarner
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This should help understand the problem:
Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law.
– Douglas Hofstadter, Gödel, Escher, Bach: An Eternal Golden Braid
#4
Posted 25 April 2011 - 08:01 AM
Apprentice123
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gregwarner said:
This should help understand the problem:
OK. Thank you, I find A is 6.67% more faster that B
#5
Posted 25 April 2011 - 03:19 PM
Apprentice123
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In this problem:
Consider the execution of a program P with 7.5x10^9 instructions on a machine operating at 5GHz and with a CPI of 0.8. What is the runtime?
My solution:
Tcpu = (7.5x10^9 x 0.8)/(5x10^9) = 1.2s
It's correct ?
Consider the execution of a program P with 7.5x10^9 instructions on a machine operating at 5GHz and with a CPI of 0.8. What is the runtime?
My solution:
Tcpu = (7.5x10^9 x 0.8)/(5x10^9) = 1.2s
It's correct ?
#6
Posted 25 April 2011 - 06:11 PM
gregwarner
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Yes, you're correct.
Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law.
– Douglas Hofstadter, Gödel, Escher, Bach: An Eternal Golden Braid
#7
Posted 26 April 2011 - 06:58 AM
Apprentice123
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gregwarner said:
Yes, you're correct.
Thank you
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