Index: trunk/psphot/src/psphotModelBackground.c
===================================================================
--- trunk/psphot/src/psphotModelBackground.c	(revision 18832)
+++ trunk/psphot/src/psphotModelBackground.c	(revision 18833)
@@ -135,4 +135,6 @@
     psF32 **modelStdevData = modelStdev->image->data.F32;
 
+    // XXXX we can thread this here by running blocks in parallel
+
     // measure clipped median for subimages
     psRegion ruffRegion = {0,0,0,0};