+ cycles_per_msec = avg;
+ dprint(FD_TIME, "min=%llu, max=%llu, mean=%f, S=%f, N=%d\n",
+ (unsigned long long) minc,
+ (unsigned long long) maxc, mean, S, NR_TIME_ITERS);
+ dprint(FD_TIME, "trimmed mean=%llu, N=%d\n", (unsigned long long) avg, samples);
+
+ max_ticks = MAX_CLOCK_SEC * cycles_per_msec * 1000ULL;
+ max_mult = ULLONG_MAX / max_ticks;
+ dprint(FD_TIME, "\n\nmax_ticks=%llu, __builtin_clzll=%d, "
+ "max_mult=%llu\n", max_ticks,
+ __builtin_clzll(max_ticks), max_mult);
+
+ /*
+ * Find the largest shift count that will produce
+ * a multiplier that does not exceed max_mult
+ */
+ tmp = max_mult * cycles_per_msec / 1000000;
+ while (tmp > 1) {
+ tmp >>= 1;
+ sft++;
+ dprint(FD_TIME, "tmp=%llu, sft=%u\n", tmp, sft);
+ }
+
+ clock_shift = sft;
+ clock_mult = (1ULL << sft) * 1000000 / cycles_per_msec;
+ dprint(FD_TIME, "clock_shift=%u, clock_mult=%llu\n", clock_shift,
+ clock_mult);
+
+ /*
+ * Find the greatest power of 2 clock ticks that is less than the
+ * ticks in MAX_CLOCK_SEC_2STAGE
+ */
+ max_cycles_shift = max_cycles_mask = 0;
+ tmp = MAX_CLOCK_SEC * 1000ULL * cycles_per_msec;
+ dprint(FD_TIME, "tmp=%llu, max_cycles_shift=%u\n", tmp,
+ max_cycles_shift);
+ while (tmp > 1) {
+ tmp >>= 1;
+ max_cycles_shift++;
+ dprint(FD_TIME, "tmp=%llu, max_cycles_shift=%u\n", tmp, max_cycles_shift);
+ }
+ /*
+ * if use use (1ULL << max_cycles_shift) * 1000 / cycles_per_msec
+ * here we will have a discontinuity every
+ * (1ULL << max_cycles_shift) cycles
+ */
+ nsecs_for_max_cycles = ((1ULL << max_cycles_shift) * clock_mult)
+ >> clock_shift;
+
+ /* Use a bitmask to calculate ticks % (1ULL << max_cycles_shift) */
+ for (tmp = 0; tmp < max_cycles_shift; tmp++)
+ max_cycles_mask |= 1ULL << tmp;