3.5 Periodic Sampling

Periodic sampling is controlled by four RTIs. RTI timing_sim_after_insn specifies the start of the first sample, call its value I. RTI ss_sample_period specifies the distance (in instructions) between samples, call its value P. The second sample will start at I + P, the third at I + 2 P, etc. Sample size is specified by ss_sample_size and warmup size is specified by ss_warmup_size. If ss_sample_period is less that ss_sample_size then periodic sampling is not performed.

With the RTI settings below, the first sample starts at instruction 70000, the second at 80000, the third at 90000, etc. Each sample is 500 instructions and warmup starts 100 instructions before the sample.

     timing_sim_after_insn 70000
     ss_warmup_size          100
     ss_sample_size          500
     ss_sample_period      10000

Note that the sizes used above were made small for the convenience of those who cannot quickly distinguish 1000000 from 10000000. In a real simulation values 1000 times as large would be typical.

See Sampling and Trace Mode RTIs for detailed description of these RTIs.