tools/perf/util/tsc.c

   1 #include <linux/compiler.h>
   2 #include <linux/types.h>
   3
   4 #include "tsc.h"
   5
   6 u64 perf_time_to_tsc(u64 ns, struct perf_tsc_conversion *tc)
   7 {
   8         u64 t, quot, rem;
   9
  10         t = ns - tc->time_zero;
  11         quot = t / tc->time_mult;
  12         rem  = t % tc->time_mult;
  13         return (quot << tc->time_shift) +
  14                (rem << tc->time_shift) / tc->time_mult;
  15 }
  16
  17 u64 tsc_to_perf_time(u64 cyc, struct perf_tsc_conversion *tc)
  18 {
  19         u64 quot, rem;
  20
  21         quot = cyc >> tc->time_shift;
  22         rem  = cyc & ((1 << tc->time_shift) - 1);
  23         return tc->time_zero + quot * tc->time_mult +
  24                ((rem * tc->time_mult) >> tc->time_shift);
  25 }
  26
  27 u64 __weak rdtsc(void)
  28 {
  29         return 0;
  30 }