CODEWITHSUNDEEP
c++profilingintelinstructionsintel-vtune
Yun Li
Yun Li

Reputation: 427

Where is integer addition and subtraction event count from intel Vtune?

I am using intel VTune to profile my program.

The CPU I am using is IVY Bridge.

All the hardware instruction event can be found here:

https://software.intel.com/en-us/node/589933

FP_COMP_OPS_EXE.X87 Number of FP Computational Uops Executed this cycle. The number of FADD, FSUB, FCOM, FMULs, integer MULsand IMULs, FDIVs, FPREMs, FSQRTS, integer DIVs, and IDIVs. This event does not distinguish an FADD used in the middle of a transcendental flow from a s

FP_COMP_OPS_EXE.X87 seems to include Integer Multiplication and Integer Division; however, there is no Integer Addition and Integer Subtraction there. I can not find those two kinds of instruction either from the above website.

Can anyone tell me what is the event that counts integer addition and integer subtraction instructions?

Upvotes: 2

Views: 181

Answers (1)

Aaron Altman
Aaron Altman

Reputation: 1755

I'm reading a lot into your question, but here goes:

It's possible that if your code is computationally bound you could find ways to infer the significance of integer adds and subs without measuring them directly. For example, UOPS_RETIRED.ALL - FP_COMP_OPS_EXE.ALL would give you a very rough estimate of adds and subs, assuming that you've already done something to establish that your code is compute bound.

Have you? If not, it might help to start with VTune's basic analysis and then eliminate memory, cache and front end bottlenecks. If you've already done this, you have a few more options:

  • Cross-reference UOPS_DISPATCHED_PORT with an Ivy Bridge block diagram, or even better, a list of which specific types of arithmetic can execute on which ports (which I can't find).
  • Modify your program source, compiler flags or assembly, rerun a coarser-grained profile like basic analysis, and see whether you see an impact at the level of a measure like INST_RETIRED.ANY / CPU_CLK_UNHALTED.

Sorry there doesn't seem to be a more direct answer.

Upvotes: 2

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