int
dmu_tx_assign(dmu_tx_t *tx, uint64_t txg_how)
{
+ hrtime_t before, after;
int err;
ASSERT(tx->tx_txg == 0);
ASSERT(txg_how != 0);
ASSERT(!dsl_pool_sync_context(tx->tx_pool));
+ before = gethrtime();
+
while ((err = dmu_tx_try_assign(tx, txg_how)) != 0) {
dmu_tx_unassign(tx);
txg_rele_to_quiesce(&tx->tx_txgh);
+ after = gethrtime();
+
+ dsl_pool_tx_assign_add_usecs(tx->tx_pool,
+ (after - before) / NSEC_PER_USEC);
+
return (0);
}