/usr/share/systemtap/runtime/linux
Edit: /usr/share/systemtap/runtime/linux/timer.c (2200B)
/* -*- linux-c -*-
* Kernel Timer Functions
* Copyright (C) 2012 Red Hat Inc.
*
* This file is part of systemtap, and is free software. You can
* redistribute it and/or modify it under the terms of the GNU General
* Public License (GPL); either version 2, or (at your option) any
* later version.
*/
#ifndef _LINUX_TIMER_C_
#define _LINUX_TIMER_C_
#include "timer.h"
static void _stp_hrtimer_init(void)
{
#if defined(STAPCONF_HRTIMER_GET_RES)
struct timespec res;
hrtimer_get_res (CLOCK_MONOTONIC, &res);
stap_hrtimer_resolution = timespec_to_ns(&res);
#else
stap_hrtimer_resolution = hrtimer_resolution;
#endif
}
static inline ktime_t _stp_hrtimer_get_interval(struct stap_hrtimer_probe *stp)
{
unsigned long nsecs;
uint64_t i = stp->intrv;
if (stp->rnd != 0) {
#if 1
// XXX: why not use stp_random_pm instead of this?
int64_t r;
get_random_bytes(&r, sizeof(r));
// ensure that r is positive
r &= ((uint64_t)1 << (8*sizeof(r) - 1)) - 1;
r = _stp_mod64(NULL, r, (2*stp->rnd+1));
r -= stp->rnd;
i += r;
#else
i += _stp_random_pm(stp->rnd);
#endif
}
if (unlikely(i < stap_hrtimer_resolution))
i = stap_hrtimer_resolution;
nsecs = do_div(i, NSEC_PER_SEC);
return ktime_set(i, nsecs);
}
static inline void _stp_hrtimer_update(struct stap_hrtimer_probe *stp)
{
ktime_t time;
time = ktime_add(hrtimer_get_expires(&stp->hrtimer),
_stp_hrtimer_get_interval(stp));
hrtimer_set_expires(&stp->hrtimer, time);
}
static int
_stp_hrtimer_start(struct stap_hrtimer_probe *stp)
{
(void)hrtimer_start(&stp->hrtimer, _stp_hrtimer_get_interval(stp),
HRTIMER_MODE_REL);
return 0;
}
static int
_stp_hrtimer_create(struct stap_hrtimer_probe *stp,
hrtimer_return_t (*function)(struct hrtimer *))
{
hrtimer_init(&stp->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
stp->hrtimer.function = function;
return 0;
}
// For kernel-mode, there is no difference between cancel/delete.
static void
_stp_hrtimer_cancel(struct stap_hrtimer_probe *stp)
{
hrtimer_cancel(&stp->hrtimer);
}
static void
_stp_hrtimer_delete(struct stap_hrtimer_probe *stp)
{
_stp_hrtimer_cancel(stp);
}
#endif /* _LINUX_TIMER_C_ */