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
9 struct timeval *fio_tv = NULL;
10 int fio_gtod_offload = 0;
11 static pthread_t gtod_thread;
12 #ifdef FIO_HAVE_CPU_AFFINITY
13 static os_cpu_mask_t fio_gtod_cpumask;
14 #endif
15
fio_gtod_init(void)16 void fio_gtod_init(void)
17 {
18 if (fio_tv)
19 return;
20
21 fio_tv = smalloc(sizeof(struct timeval));
22 if (!fio_tv)
23 log_err("fio: smalloc pool exhausted\n");
24 }
25
fio_gtod_update(void)26 static void fio_gtod_update(void)
27 {
28 if (fio_tv) {
29 struct timeval __tv;
30
31 gettimeofday(&__tv, NULL);
32 fio_tv->tv_sec = __tv.tv_sec;
33 write_barrier();
34 fio_tv->tv_usec = __tv.tv_usec;
35 write_barrier();
36 }
37 }
38
39 struct gtod_cpu_data {
40 struct fio_mutex *mutex;
41 unsigned int cpu;
42 };
43
gtod_thread_main(void * data)44 static void *gtod_thread_main(void *data)
45 {
46 struct fio_mutex *mutex = data;
47
48 fio_setaffinity(gettid(), fio_gtod_cpumask);
49 fio_mutex_up(mutex);
50
51 /*
52 * As long as we have jobs around, update the clock. It would be nice
53 * to have some way of NOT hammering that CPU with gettimeofday(),
54 * but I'm not sure what to use outside of a simple CPU nop to relax
55 * it - we don't want to lose precision.
56 */
57 while (threads) {
58 fio_gtod_update();
59 nop;
60 }
61
62 return NULL;
63 }
64
fio_start_gtod_thread(void)65 int fio_start_gtod_thread(void)
66 {
67 struct fio_mutex *mutex;
68 pthread_attr_t attr;
69 int ret;
70
71 mutex = fio_mutex_init(FIO_MUTEX_LOCKED);
72 if (!mutex)
73 return 1;
74
75 pthread_attr_init(&attr);
76 pthread_attr_setstacksize(&attr, PTHREAD_STACK_MIN);
77 ret = pthread_create(>od_thread, &attr, gtod_thread_main, mutex);
78 pthread_attr_destroy(&attr);
79 if (ret) {
80 log_err("Can't create gtod thread: %s\n", strerror(ret));
81 goto err;
82 }
83
84 ret = pthread_detach(gtod_thread);
85 if (ret) {
86 log_err("Can't detatch gtod thread: %s\n", strerror(ret));
87 goto err;
88 }
89
90 dprint(FD_MUTEX, "wait on startup_mutex\n");
91 fio_mutex_down(mutex);
92 dprint(FD_MUTEX, "done waiting on startup_mutex\n");
93 err:
94 fio_mutex_remove(mutex);
95 return ret;
96 }
97
fio_gtod_set_cpu(unsigned int cpu)98 void fio_gtod_set_cpu(unsigned int cpu)
99 {
100 #ifdef FIO_HAVE_CPU_AFFINITY
101 fio_cpu_set(&fio_gtod_cpumask, cpu);
102 #endif
103 }
104