An example of using __rdtsc, __cpuid and __rdtscp to measure performance

Descriptions

• According to How to Benchmark Code Execution Times on Intel® IA-32 and IA-64 Instruction Set Architectures.
• These functions are built in (that is, intrinsic) to the compiler, which are referred to as intrinsic functions or intrinsics. An intrinsic is often faster than the equivalent inline assembly. I have to use these functions because Microsoft compiler doesn't support inline assembler on x64 processors.

Downloads

• http://adf.ly/1BrI8R

Results

• Loading hello module...
  loop_size:0 >>>> variance(cycles): 3; max_deviation: 4 ;min time: 44
  loop_size:1 >>>> variance(cycles): 32; max_deviation: 1712 ;min time: 44
  loop_size:2 >>>> variance(cycles): 3; max_deviation: 200 ;min time: 44
  .........
  .........
  loop_size:997 >>>> variance(cycles): 2; max_deviation: 4 ;min time: 44
  loop_size:998 >>>> variance(cycles): 3; max_deviation: 4 ;min time: 44
  loop_size:999 >>>> variance(cycles): 48; max_deviation: 2128 ;min time: 44
  
  total number of spurious min values = 0
  total variance = 48316
  absolute max deviation = 1537444
  variance of variances = 740609432999
  variance of minimum values = 0
  

Comments

• The result is just the same as the version using inline assembler.

Resources

• How to Benchmark Code Execution Times on Intel® IA-32 and IA-64 Instruction Set Architectures
• Compiler Intrinsics