4045 zfs write throttle & i/o scheduler performance work
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>

*** 182,192 ****
          .zo_metaslab_gang_bang = 32 << 10
  };
  
  extern uint64_t metaslab_gang_bang;
  extern uint64_t metaslab_df_alloc_threshold;
! extern uint64_t zfs_deadman_synctime;
  
  static ztest_shared_opts_t *ztest_shared_opts;
  static ztest_shared_opts_t ztest_opts;
  
  typedef struct ztest_shared_ds {
--- 182,192 ----
          .zo_metaslab_gang_bang = 32 << 10
  };
  
  extern uint64_t metaslab_gang_bang;
  extern uint64_t metaslab_df_alloc_threshold;
! extern uint64_t zfs_deadman_synctime_ms;
  
  static ztest_shared_opts_t *ztest_shared_opts;
  static ztest_shared_opts_t ztest_opts;
  
  typedef struct ztest_shared_ds {
*** 5323,5336 ****
          ztest_shared_t *zs = arg;
          spa_t *spa = ztest_spa;
          hrtime_t delta, total = 0;
  
          for (;;) {
!                 delta = (zs->zs_thread_stop - zs->zs_thread_start) /
!                     NANOSEC + zfs_deadman_synctime;
  
!                 (void) poll(NULL, 0, (int)(1000 * delta));
  
                  /*
                   * If the pool is suspended then fail immediately. Otherwise,
                   * check to see if the pool is making any progress. If
                   * vdev_deadman() discovers that there hasn't been any recent
--- 5323,5336 ----
          ztest_shared_t *zs = arg;
          spa_t *spa = ztest_spa;
          hrtime_t delta, total = 0;
  
          for (;;) {
!                 delta = zs->zs_thread_stop - zs->zs_thread_start +
!                     MSEC2NSEC(zfs_deadman_synctime_ms);
  
!                 (void) poll(NULL, 0, (int)NSEC2MSEC(delta));
  
                  /*
                   * If the pool is suspended then fail immediately. Otherwise,
                   * check to see if the pool is making any progress. If
                   * vdev_deadman() discovers that there hasn't been any recent
*** 5337,5352 ****
                   * I/Os then it will end up aborting the tests.
                   */
                  if (spa_suspended(spa)) {
                          fatal(0, "aborting test after %llu seconds because "
                              "pool has transitioned to a suspended state.",
!                             zfs_deadman_synctime);
                          return (NULL);
                  }
                  vdev_deadman(spa->spa_root_vdev);
  
!                 total += zfs_deadman_synctime;
                  (void) printf("ztest has been running for %lld seconds\n",
                      total);
          }
  }
  
--- 5337,5352 ----
                   * I/Os then it will end up aborting the tests.
                   */
                  if (spa_suspended(spa)) {
                          fatal(0, "aborting test after %llu seconds because "
                              "pool has transitioned to a suspended state.",
!                             zfs_deadman_synctime_ms / 1000);
                          return (NULL);
                  }
                  vdev_deadman(spa->spa_root_vdev);
  
!                 total += zfs_deadman_synctime_ms/1000;
                  (void) printf("ztest has been running for %lld seconds\n",
                      total);
          }
  }
  
*** 6071,6081 ****
          char *fd_data_str = getenv("ZTEST_FD_DATA");
  
          (void) setvbuf(stdout, NULL, _IOLBF, 0);
  
          dprintf_setup(&argc, argv);
!         zfs_deadman_synctime = 300;
  
          ztest_fd_rand = open("/dev/urandom", O_RDONLY);
          ASSERT3S(ztest_fd_rand, >=, 0);
  
          if (!fd_data_str) {
--- 6071,6081 ----
          char *fd_data_str = getenv("ZTEST_FD_DATA");
  
          (void) setvbuf(stdout, NULL, _IOLBF, 0);
  
          dprintf_setup(&argc, argv);
!         zfs_deadman_synctime_ms = 300000;
  
          ztest_fd_rand = open("/dev/urandom", O_RDONLY);
          ASSERT3S(ztest_fd_rand, >=, 0);
  
          if (!fd_data_str) {