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 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 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 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 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 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