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 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 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 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 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 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