60 lines
1.2 KiB
C
60 lines
1.2 KiB
C
#include <stdbool.h>
|
|
#include <errno.h>
|
|
|
|
#include <linux/perf_event.h>
|
|
|
|
#include "../../perf.h"
|
|
#include "../../util/types.h"
|
|
#include "../../util/debug.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);
|
|
}
|
|
|
|
int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc,
|
|
struct perf_tsc_conversion *tc)
|
|
{
|
|
bool cap_user_time_zero;
|
|
u32 seq;
|
|
int i = 0;
|
|
|
|
while (1) {
|
|
seq = pc->lock;
|
|
rmb();
|
|
tc->time_mult = pc->time_mult;
|
|
tc->time_shift = pc->time_shift;
|
|
tc->time_zero = pc->time_zero;
|
|
cap_user_time_zero = pc->cap_user_time_zero;
|
|
rmb();
|
|
if (pc->lock == seq && !(seq & 1))
|
|
break;
|
|
if (++i > 10000) {
|
|
pr_debug("failed to get perf_event_mmap_page lock\n");
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
if (!cap_user_time_zero)
|
|
return -EOPNOTSUPP;
|
|
|
|
return 0;
|
|
}
|