linux/tools/perf/util/tsc.c

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#include <linux/compiler.h>
#include <linux/types.h>
#include "tsc.h"
u64 perf_time_to_tsc(u64 ns, struct perf_tsc_conversion *tc)
{
u64 t, quot, rem;
t = ns - tc->time_zero;
quot = t / tc->time_mult;
rem = t % tc->time_mult;
return (quot << tc->time_shift) +
(rem << tc->time_shift) / tc->time_mult;
}
u64 tsc_to_perf_time(u64 cyc, struct perf_tsc_conversion *tc)
{
u64 quot, rem;
quot = cyc >> tc->time_shift;
rem = cyc & ((1 << tc->time_shift) - 1);
return tc->time_zero + quot * tc->time_mult +
((rem * tc->time_mult) >> tc->time_shift);
}
u64 __weak rdtsc(void)
{
return 0;
}