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 static os_cpu_mask_t fio_gtod_cpumask;
13
fio_gtod_init(void)14 void 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
fio_gtod_update(void)24 static 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
37 struct gtod_cpu_data {
38 struct fio_mutex *mutex;
39 unsigned int cpu;
40 };
41
gtod_thread_main(void * data)42 static 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
fio_start_gtod_thread(void)63 int 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(>od_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");
91 err:
92 fio_mutex_remove(mutex);
93 return ret;
94 }
95
fio_gtod_set_cpu(unsigned int cpu)96 void 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