performance? The countdown time
There are two indicators: one is called the response time or execution time; one is the throughput or bandwidth, which can be two to understand how much work time and act.
= 1 while the performance / response time
CPU clock: time unit of the computer
CPU execution time of the program X = CPU clock cycles clock cycle time
CUP frequency: for example, frequency is 2.8GHz, so that the number of simple instructions in the CPU of one second, may be performed 2.8G article; then the clock cycle time is 1 / 2.8G, the higher the frequency, the meaning table go faster, CPU will go along faster;
Improve performance is to consider clock cycle time and the number of clock cycles shortened clock cycle time, i.e. to enhance the frequency, i.e. a good transducer CPU; the other is to reduce the number of CPU clock cycles of the program,
While the average number of clock cycles of clock cycles = number of instructions each instruction of number X, the number of instructions the compiler has controlled, so that the CPU can be the average number of clock cycles required for instruction pipelining reduced by