1#include <unistd.h>
2#include <math.h>
3#include <sys/time.h>
4#include <time.h>
5
6#include "fio.h"
7#include "smalloc.h"
8
9struct timeval *fio_tv = NULL;
10int fio_gtod_offload = 0;
11static pthread_t gtod_thread;
12static os_cpu_mask_t fio_gtod_cpumask;
13
14void fio_gtod_init(void)
15{
16	if (fio_tv)
17		return;
18
19	fio_tv = smalloc(sizeof(struct timeval));
20	if (!fio_tv)
21		log_err("fio: smalloc pool exhausted\n");
22}
23
24static void fio_gtod_update(void)
25{
26	if (fio_tv) {
27		struct timeval __tv;
28
29		gettimeofday(&__tv, NULL);
30		fio_tv->tv_sec = __tv.tv_sec;
31		write_barrier();
32		fio_tv->tv_usec = __tv.tv_usec;
33		write_barrier();
34	}
35}
36
37struct gtod_cpu_data {
38	struct fio_mutex *mutex;
39	unsigned int cpu;
40};
41
42static void *gtod_thread_main(void *data)
43{
44	struct fio_mutex *mutex = data;
45
46	fio_setaffinity(gettid(), fio_gtod_cpumask);
47	fio_mutex_up(mutex);
48
49	/*
50	 * As long as we have jobs around, update the clock. It would be nice
51	 * to have some way of NOT hammering that CPU with gettimeofday(),
52	 * but I'm not sure what to use outside of a simple CPU nop to relax
53	 * it - we don't want to lose precision.
54	 */
55	while (threads) {
56		fio_gtod_update();
57		nop;
58	}
59
60	return NULL;
61}
62
63int fio_start_gtod_thread(void)
64{
65	struct fio_mutex *mutex;
66	pthread_attr_t attr;
67	int ret;
68
69	mutex = fio_mutex_init(FIO_MUTEX_LOCKED);
70	if (!mutex)
71		return 1;
72
73	pthread_attr_init(&attr);
74	pthread_attr_setstacksize(&attr, 2 * PTHREAD_STACK_MIN);
75	ret = pthread_create(&gtod_thread, &attr, gtod_thread_main, mutex);
76	pthread_attr_destroy(&attr);
77	if (ret) {
78		log_err("Can't create gtod thread: %s\n", strerror(ret));
79		goto err;
80	}
81
82	ret = pthread_detach(gtod_thread);
83	if (ret) {
84		log_err("Can't detach gtod thread: %s\n", strerror(ret));
85		goto err;
86	}
87
88	dprint(FD_MUTEX, "wait on startup_mutex\n");
89	fio_mutex_down(mutex);
90	dprint(FD_MUTEX, "done waiting on startup_mutex\n");
91err:
92	fio_mutex_remove(mutex);
93	return ret;
94}
95
96void fio_gtod_set_cpu(unsigned int cpu)
97{
98#ifdef FIO_HAVE_CPU_AFFINITY
99	fio_cpu_set(&fio_gtod_cpumask, cpu);
100#endif
101}
102