tools/perf/util/tsc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/compiler.h>
   3 #include <linux/types.h>
   4
   5 #include "tsc.h"
   6
   7 u64 perf_time_to_tsc(u64 ns, struct perf_tsc_conversion *tc)
   8 {
   9         u64 t, quot, rem;
  10
  11         t = ns - tc->time_zero;
  12         quot = t / tc->time_mult;
  13         rem  = t % tc->time_mult;
  14         return (quot << tc->time_shift) +
  15                (rem << tc->time_shift) / tc->time_mult;
  16 }
  17
  18 u64 tsc_to_perf_time(u64 cyc, struct perf_tsc_conversion *tc)
  19 {
  20         u64 quot, rem;
  21
  22         quot = cyc >> tc->time_shift;
  23         rem  = cyc & (((u64)1 << tc->time_shift) - 1);
  24         return tc->time_zero + quot * tc->time_mult +
  25                ((rem * tc->time_mult) >> tc->time_shift);
  26 }
  27
  28 u64 __weak rdtsc(void)
  29 {
  30         return 0;
  31 }