helper_thread.c

   1 #ifdef CONFIG_VALGRIND_DEV
   2 #include <valgrind/drd.h>
   3 #else
   4 #define DRD_IGNORE_VAR(x) do { } while (0)
   5 #endif
   6
   7 #include "fio.h"
   8 #include "smalloc.h"
   9 #include "helper_thread.h"
  10 #include "steadystate.h"
  11 #include "pshared.h"
  12
  13 enum action {
  14         A_EXIT          = 1,
  15         A_RESET         = 2,
  16         A_DO_STAT       = 3,
  17 };
  18
  19 static struct helper_data {
  20         volatile int exit;
  21         int pipe[2]; /* 0: read end; 1: write end. */
  22         struct sk_out *sk_out;
  23         pthread_t thread;
  24         struct fio_sem *startup_sem;
  25 } *helper_data;
  26
  27 void helper_thread_destroy(void)
  28 {
  29         close(helper_data->pipe[0]);
  30         close(helper_data->pipe[1]);
  31         sfree(helper_data);
  32 }
  33
  34 static void submit_action(enum action a)
  35 {
  36         const uint8_t data = a;
  37         int ret;
  38
  39         if (!helper_data)
  40                 return;
  41
  42         ret = write(helper_data->pipe[1], &data, sizeof(data));
  43         assert(ret == 1);
  44 }
  45
  46 void helper_reset(void)
  47 {
  48         submit_action(A_RESET);
  49 }
  50
  51 /*
  52  * May be invoked in signal handler context and hence must only call functions
  53  * that are async-signal-safe. See also
  54  * https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04_03.
  55  */
  56 void helper_do_stat(void)
  57 {
  58         submit_action(A_DO_STAT);
  59 }
  60
  61 bool helper_should_exit(void)
  62 {
  63         if (!helper_data)
  64                 return true;
  65
  66         return helper_data->exit;
  67 }
  68
  69 void helper_thread_exit(void)
  70 {
  71         helper_data->exit = 1;
  72         submit_action(A_EXIT);
  73         pthread_join(helper_data->thread, NULL);
  74 }
  75
  76 static void *helper_thread_main(void *data)
  77 {
  78         struct helper_data *hd = data;
  79         unsigned int msec_to_next_event, next_log, next_ss = STEADYSTATE_MSEC;
  80         struct timespec ts, last_du, last_ss;
  81         uint8_t action;
  82         int ret = 0;
  83
  84         sk_out_assign(hd->sk_out);
  85
  86 #ifdef CONFIG_PTHREAD_CONDATTR_SETCLOCK
  87         clock_gettime(CLOCK_MONOTONIC, &ts);
  88 #else
  89         clock_gettime(CLOCK_REALTIME, &ts);
  90 #endif
  91         memcpy(&last_du, &ts, sizeof(ts));
  92         memcpy(&last_ss, &ts, sizeof(ts));
  93
  94         fio_sem_up(hd->startup_sem);
  95
  96         msec_to_next_event = DISK_UTIL_MSEC;
  97         while (!ret && !hd->exit) {
  98                 uint64_t since_du, since_ss = 0;
  99                 struct timeval timeout = {
 100                         .tv_sec  = DISK_UTIL_MSEC / 1000,
 101                         .tv_usec = (DISK_UTIL_MSEC % 1000) * 1000,
 102                 };
 103                 fd_set rfds, efds;
 104
 105                 timespec_add_msec(&ts, msec_to_next_event);
 106
 107                 if (read(hd->pipe[0], &action, sizeof(action)) < 0) {
 108                         FD_ZERO(&rfds);
 109                         FD_SET(hd->pipe[0], &rfds);
 110                         FD_ZERO(&efds);
 111                         FD_SET(hd->pipe[0], &efds);
 112                         select(1, &rfds, NULL, &efds, &timeout);
 113                         if (read(hd->pipe[0], &action, sizeof(action)) < 0)
 114                                 action = 0;
 115                 }
 116
 117 #ifdef CONFIG_PTHREAD_CONDATTR_SETCLOCK
 118                 clock_gettime(CLOCK_MONOTONIC, &ts);
 119 #else
 120                 clock_gettime(CLOCK_REALTIME, &ts);
 121 #endif
 122
 123                 if (action == A_RESET) {
 124                         last_du = ts;
 125                         last_ss = ts;
 126                 }
 127
 128                 since_du = mtime_since(&last_du, &ts);
 129                 if (since_du >= DISK_UTIL_MSEC || DISK_UTIL_MSEC - since_du < 10) {
 130                         ret = update_io_ticks();
 131                         timespec_add_msec(&last_du, DISK_UTIL_MSEC);
 132                         msec_to_next_event = DISK_UTIL_MSEC;
 133                         if (since_du >= DISK_UTIL_MSEC)
 134                                 msec_to_next_event -= (since_du - DISK_UTIL_MSEC);
 135                 } else
 136                         msec_to_next_event = DISK_UTIL_MSEC - since_du;
 137
 138                 if (action == A_DO_STAT)
 139                         __show_running_run_stats();
 140
 141                 next_log = calc_log_samples();
 142                 if (!next_log)
 143                         next_log = DISK_UTIL_MSEC;
 144
 145                 if (steadystate_enabled) {
 146                         since_ss = mtime_since(&last_ss, &ts);
 147                         if (since_ss >= STEADYSTATE_MSEC || STEADYSTATE_MSEC - since_ss < 10) {
 148                                 steadystate_check();
 149                                 timespec_add_msec(&last_ss, since_ss);
 150                                 if (since_ss > STEADYSTATE_MSEC)
 151                                         next_ss = STEADYSTATE_MSEC - (since_ss - STEADYSTATE_MSEC);
 152                                 else
 153                                         next_ss = STEADYSTATE_MSEC;
 154                         } else
 155                                 next_ss = STEADYSTATE_MSEC - since_ss;
 156                 }
 157
 158                 msec_to_next_event = min(min(next_log, msec_to_next_event), next_ss);
 159                 dprint(FD_HELPERTHREAD, "since_ss: %llu, next_ss: %u, next_log: %u, msec_to_next_event: %u\n", (unsigned long long)since_ss, next_ss, next_log, msec_to_next_event);
 160
 161                 if (!is_backend)
 162                         print_thread_status();
 163         }
 164
 165         fio_writeout_logs(false);
 166
 167         sk_out_drop();
 168         return NULL;
 169 }
 170
 171 int helper_thread_create(struct fio_sem *startup_sem, struct sk_out *sk_out)
 172 {
 173         struct helper_data *hd;
 174         int ret;
 175
 176         hd = scalloc(1, sizeof(*hd));
 177
 178         setup_disk_util();
 179         steadystate_setup();
 180
 181         hd->sk_out = sk_out;
 182
 183 #ifdef __linux__
 184         ret = pipe2(hd->pipe, O_CLOEXEC);
 185 #else
 186         ret = pipe(hd->pipe);
 187 #endif
 188         if (ret)
 189                 return 1;
 190
 191         ret = fcntl(hd->pipe[0], F_SETFL, O_NONBLOCK);
 192         assert(ret >= 0);
 193
 194         hd->startup_sem = startup_sem;
 195
 196         DRD_IGNORE_VAR(helper_data);
 197
 198         ret = pthread_create(&hd->thread, NULL, helper_thread_main, hd);
 199         if (ret) {
 200                 log_err("Can't create helper thread: %s\n", strerror(ret));
 201                 return 1;
 202         }
 203
 204         helper_data = hd;
 205
 206         dprint(FD_MUTEX, "wait on startup_sem\n");
 207         fio_sem_down(startup_sem);
 208         dprint(FD_MUTEX, "done waiting on startup_sem\n");
 209         return 0;
 210 }