Hi
I'm trying to understand vTunes metric "Retired insrtuctions". I've read some previous questions/answers in this forum but don't find the answer to my question. I'm going to explain my question using an example. Here is a small piece of code from a performance tuning I did:
(This is C# code) As can be seen, there are 144 vs 999 million instructions retired on row 67 and 68. The loop should make each of the line execute as many times. So far so good since each lines contains several instructions. However, when I show the assembly code for row 67 for instance, this is where I get lost. It shows the following instructions with the following instructions retired count. 27, 57, and 60 adds up to 144 but why are there a different count for each instruction?
I guess the first greyed out mov instruction has some uncertainty since it is greyed out. (?) But the other two. Why the difference? Is it due to speculation? But if so, should not the imul intructions have more counts than the add instruction. Unless execution is not actually in this order. Some advice on how to interpret these numbers, please.