magnusah/tsccal

TSC calibrator

TSC Calibrator

Gets the frequency of the TSC so that values from rdtsc can be converted to time, much faster than system calls and should work with any compiler (i think).

Usage

tsc_calibrate()
Gets the TSC frequency using the default parameters defined in tsc.c
With default parameters calibration takes a bit over a second.

_tsc_calibrate(uint64_t warmup_count, uint64_t sample_count, uint64_t sample_duration, uint64_t deviation)
Gets the TSC frequency using the passed parameters.
warmup_count is the number of the first samples to be used as a warmup (not used for finding the frequency)
sample_count is the number of samples desired to be used for calculating the frequency
sample_duration is the duration of each sample in nanoseconds, higher sample duration means higher accuracy, but too high sample duration increases the chance of the process scheduler ruining the sample
deviation is value representing how tight of a standard deviation should be used for processing the results (higher is tighter)

tsc_toNano(uint64_t ticks)
returns ticks as a number of nanoseconds as a uint64_t

tsc_toMicro(uint64_t ticks)
returns ticks as a number of microseconds as a uint64_t

tsc_toMilli(uint64_t ticks)
returns ticks as a number of milliseconds as a uint64_t

tsc_toSec(uint64_t ticks)
returns ticks as a number of seconds as a uint64_t

tsc_toNanoF(double ticks)
returns ticks as a number of nanoseconds as a double

tsc_toMicroF(double ticks)
returns ticks as a number of microseconds as a double

tsc_toMilliF(double ticks)
returns ticks as a number of milliseconds as a double

tsc_toSecF(double ticks)
returns ticks as a number of seconds as a double

tsccal's Issues

work amazing but little issue

best to force the calibration in first core by using SetThreadAffinityMask function cause rdtsc not work well with multi core since SetThreadAffinityMask not work well on my windows i use the command /affinity and thats work better

start /affinity 1 tsc.exe / for HyperThreading/SMT off
start /affinity 3 tsc.exe / for SMT/HyperThreading On

same goes to SetThreadAffinityMask