diff --git a/ui/medashare/cli.py b/ui/medashare/cli.py
index e710fc2..dea2760 100644
--- a/ui/medashare/cli.py
+++ b/ui/medashare/cli.py
@@ -19,7 +19,7 @@ if False:
 	logging.getLogger('sqlalchemy').addHandler(_handler)
 	logging.getLogger('sqlalchemy.engine').setLevel(lvl)
 
-from .utils import _debprint
+from .utils import _debprint, enable_debug, disable_debug
 
 def _getquery(q, objstr):
 	return repr(str(q.compile(objstr._engine,
@@ -841,6 +841,7 @@ class FileObject(MDBase):
 		#print(repr(self), repr(s), s.st_mtime, file=_real_stderr)
 		if self.mtime.timestamp() != mtimets or \
 		    self.size != s.st_size:
+			_debprint('times:', self.mtime.timestamp(), mtimets)
 			raise ValueError('file %s has changed' %
 			    repr(self.filename))
 
@@ -1206,6 +1207,18 @@ def checkforfile(objstr, curfile, ask=False):
 
 	return fobj
 
+from contextlib import contextmanager
+import time
+
+@contextmanager
+def timeblock(tag):
+	s = time.time()
+	try:
+		yield
+	finally:
+		e = time.time()
+		_debprint(tag, e - s)
+
 @init_datastructs
 def cmd_interactive(options, persona, objstr, cache):
 	files = [ pathlib.Path(x) for x in options.files ]
@@ -1219,33 +1232,36 @@ def cmd_interactive(options, persona, objstr, cache):
 		files = sorted(pathlib.Path('.').iterdir())
 
 	while True:
-		curfile = files[idx]
+		with timeblock('checkfile'):
+			curfile = files[idx]
 
-		fobj = checkforfile(objstr, curfile, not autoskip)
+			fobj = checkforfile(objstr, curfile, not autoskip)
+			#_debprint(repr(fobj))
 
-		if fobj is None and autoskip and idx > 0 and idx < len(files) - 1:
-			# if we are auto skipping, and within range, continue
-			if inp == '1':
-				idx = max(0, idx - 1)
-				continue
-			if inp == '2':
-				idx = min(len(files) - 1, idx + 1)
-				continue
+			if fobj is None and autoskip and idx > 0 and idx < len(files) - 1:
+				# if we are auto skipping, and within range, continue
+				if inp == '1':
+					idx = max(0, idx - 1)
+					continue
+				if inp == '2':
+					idx = min(len(files) - 1, idx + 1)
+					continue
 
 		print('Current: %s' % repr(str(curfile)))
 
-		if fobj is None:
-			print('No file object for this file.')
-		else:
-			try:
-				objs = objstr.by_file(curfile)
-			except KeyError:
-				print('No tags or metadata object for this file.')
+		with timeblock('byfile'):
+			if fobj is None:
+				print('No file object for this file.')
 			else:
-				for k, v in _iterdictlist(objs[0]):
-					if k in { 'sig', 'hashes' }:
-						continue
-					print('%s:\t%s' % (k, v))
+				try:
+					objs = objstr.by_file(curfile)
+				except KeyError:
+					print('No tags or metadata object for this file.')
+				else:
+					for k, v in _iterdictlist(objs[0]):
+						if k in { 'sig', 'hashes' }:
+							continue
+						print('%s:\t%s' % (k, v))
 
 		if idx == 0:
 			print('1) No previous file')
@@ -1668,6 +1684,9 @@ def main():
 
 	parser = argparse.ArgumentParser()
 
+	parser.add_argument('--debug', action='store_true',
+	    default=False, help='enable debug output')
+
 	parser.add_argument('--db', '-d', type=str,
 	    help='base name for storage')
 
@@ -1762,6 +1781,11 @@ def main():
 
 	options = parser.parse_args()
 
+	if options.debug:
+		enable_debug()
+	else:
+		disable_debug()
+
 	try:
 		fun = options.func
 	except AttributeError:
diff --git a/ui/medashare/utils.py b/ui/medashare/utils.py
index 7832385..e1fca56 100644
--- a/ui/medashare/utils.py
+++ b/ui/medashare/utils.py
@@ -6,7 +6,22 @@ import uuid
 
 _real_stderr = sys.stderr
 
+DEBUG = True
+
+def enable_debug():
+	global DEBUG
+
+	DEBUG = True
+
+def disable_debug():
+	global DEBUG
+
+	DEBUG = False
+
 def _debprint(*args): # pragma: no cover
+	if not DEBUG:
+		return
+
 	import traceback, sys, os.path
 	st = traceback.extract_stack(limit=2)[0]