diff --git a/pyproject.toml b/pyproject.toml
index 1aa17f9..7718cf7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "rda_python_dsquasar"
-version = "3.0.15"
+version = "3.0.16"
 authors = [
   { name="Zaihua Ji", email="zji@ucar.edu" },
 ]
diff --git a/src/rda_python_dsquasar/dsquasar.py b/src/rda_python_dsquasar/dsquasar.py
index f92985c..c09000d 100644
--- a/src/rda_python_dsquasar/dsquasar.py
+++ b/src/rda_python_dsquasar/dsquasar.py
@@ -611,7 +611,7 @@ def backup_dataset_files(self, dsfiles, backflag):
                qinfo['dslocks'].remove(dsid)
             qinfo['dsids'] = []
       if self.PGBACK['mproc'] > 1:
-         self.check_child(None, 0, self.LOGWRN, 1)   # wait all child processes done
+         self.wait_all_children()   # wait all child processes done
          self.confirm_quasar_counts(qinfo, qinfo['abids'], "status = 'T'")   # recount confirmed backups from RDADB
       if qinfo['dslocks']:
          for dsid in qinfo['dslocks']:
@@ -728,7 +728,7 @@ def backup_dataset_infiles(self, dsfiles, backflag):
             self.unlock_backup_datasets(qinfo, dslocks)
          if self.PGBACK['dolock']: self.unlock_backup_datasets(qinfo, [dsid])
       if self.PGBACK['mproc'] > 1:
-         self.check_child(None, 0, self.LOGWRN, 1)   # wait all child processes done
+         self.wait_all_children()   # wait all child processes done
          self.confirm_quasar_counts(qinfo, qinfo['abids'], "status = 'T'")   # recount confirmed backups from RDADB
       qcnt = qinfo['qcnt']
       if qcnt > 0:
@@ -769,7 +769,7 @@ def backup_dataset_tarfiles(self, dsfiles, backflag):
          self.transfer_quasar_tarfiles(qinfo)
       if qinfo['size'] > 0: self.transfer_quasar_tarfiles(qinfo)
       if self.PGBACK['mproc'] > 1:
-         self.check_child(None, 0, self.LOGWRN, 1)   # wait all child processes done
+         self.wait_all_children()   # wait all child processes done
          self.confirm_quasar_counts(qinfo, list(bfiles), "status = 'A'")   # recount confirmed backups from RDADB
       qcnt = qinfo['qcnt']
       if qcnt > 0:
@@ -906,6 +906,20 @@ def check_batch_deadline(self):
       self.report_dscheck_email(title, 1)
       self.PGLOG.update(saved)
 
+   # wait for every child process to finish, checking the walltime deadline between polls.
+   # check_child(..., 1) does the waiting inside its own loop, so a phase that ends with the
+   # last tar children still running would sit there for the rest of the run without ever
+   # reaching a deadline check - the parent has no per-item loop left to guard. polling with
+   # dowait 0 and sleeping here keeps the same cadence and wait message as check_child does.
+   def wait_all_children(self):
+      if self.PGBACK['mproc'] < 2: return
+      i = 0
+      while True:
+         self.check_batch_deadline()
+         if self.check_child(None, 0, self.LOGWRN, 0) < 1: break
+         self.show_wait_message(i, "{}: wait child processes".format(self.PGSIG['DSTR']), self.LOGWRN, 1)
+         i += 1
+
    # recompute the confirmed backup counts from RDADB after all child processes
    # finished, so a multi-process summary reflects succeeded (not just started) work
    def confirm_quasar_counts(self, qinfo, bids, dcnd):
@@ -1389,6 +1403,10 @@ def gather_dataset_files(self, dsfiles, unlock = True, sizes = None):
          dcnt = len(mrecs['dsid']) if mrecs else 0
          pgrecs = [self.onerecord(mrecs, i) for i in range(dcnt)]
       for pgrec in pgrecs:
+         # a gather is not free: it queries every dataset, and each one another worker holds
+         # costs an rdaps call to check that worker's pid. a run under dscheck does two of
+         # them before any work, and -A 3 does a third one before tarring
+         self.check_batch_deadline()
          dsid = pgrec['dsid']
          if unlock and pgrec['pid'] and self.lock_dataset(dsid, 0, self.LOGACT) < 1: continue
          fcnt += self.get_dataset_files(dsid, dsfiles, pgrec['backflag'], logact, sizes)
@@ -1413,6 +1431,7 @@ def gather_dataset_infiles(self, dsfiles):
          pgrecs = self.pgmget("bfile", flds, dcnd, self.LGWNEX)
          bcnt = len(pgrecs['bid']) if pgrecs else 0
          for i in range(bcnt):
+            self.check_batch_deadline()
             cnt = self.get_backup_infile(dsfiles, self.onerecord(pgrecs, i))
             if cnt:
                icnt += 1
@@ -1438,6 +1457,7 @@ def gather_dataset_tarfiles(self, dsfiles):
          pgrecs = self.pgmget("bfile", flds, dcnd, self.LGWNEX)
          bcnt = len(pgrecs['bid']) if pgrecs else 0
          for i in range(bcnt):
+            self.check_batch_deadline()
             cnt = self.get_backup_tarfile(dsfiles, self.onerecord(pgrecs, i))
             if cnt:
                tcnt += 1