CPI means «Instructions per cycle«, From English, which in Spanish keeps the same dictionary because it means« Instructions per cycle ». But what and what effect does this have on determining the processor's performance? Let's see it.
What is the CPI processor
Instructions per cycle or CPI indicate is the number of commands that the processor can execute in one clock cycle. In other words, it is an indicator of the processor's performance, because the greater the number of instructions per cycle, the greater the number of tasks that can execute simultaneously.
Of course, to know the processor's final performance, there are other factors that are more influential than IPC, such as clock frequency and compiler (instructions).
So the IPC tells us how many instructions a processor performs for each clock cycle. These commands are executed in several phases, and where we have only one command per phase, under ideal conditions we will say that one command is executed per cycle (IPC = 1). Of course, there is not only one command that is executed per category, and as a result The CPI value provided remains an average value.
How does the CPI influence performance?
There are systems that perform performance testing, but as we explained before the operation depends on many factors than the IPC and, in this case, the integrator is important, or the type of instructions it uses. For this reason tests must be independent, and that they use the instructions that the processor will use in a standard way so that the IPC value is a reliable indicator of performance.
When we want to measure the performance of a processor, what we do is to measure the time it takes to create a teaching program. This time is equal to the following formula:
The time (T) is equal to the number of orders (N) multiplied by 1 during CPI, multiplied by the processor frequency (f).
In other words, the regression we have is that the CPI equals the number of orders (N) by 1 divided by time (T), multiplied by the quantity (f).
It is important to note that the number or number of commands is a value that depends on the integrator used, as we have explained earlier.
So also as a summary, IPC is an indicator of processor performance, too the greater its value, multiple commands can be performed for each clock cycle as well its effectiveness will be higher.
