Index: trunk/psphot/src/psphotStackReadout.c
===================================================================
--- trunk/psphot/src/psphotStackReadout.c	(revision 34266)
+++ trunk/psphot/src/psphotStackReadout.c	(revision 34317)
@@ -2,4 +2,5 @@
 
 static bool psphotStackLoadWCS(pmConfig *config, const pmFPAview *view, const char *filerule);
+static void logMemStats(const char *heading);
 
 // we have 3 possible real filesets:
@@ -51,4 +52,6 @@
     // by the multiple threads, not the total time used by all threads.
     psTimerStart ("psphotReadout");
+
+    logMemStats("Start");
 
     pmModelClassSetLimits(PM_MODEL_LIMITS_LAX); // allow models to have ugly fits (eg, central cusp)
@@ -82,6 +85,10 @@
     }
 
-    // Generate the mask and weight images (if not supplied) and set mask bits
+    // Generate the mask and weight images (if not supplied) and set mask bits. 
+    // This also insures that all invalid pixels are masked (this is done for STACK_CNV in psphotStackMatchPSFs)
     if (!psphotSetMaskAndVariance (config, view, STACK_DET)) {
+	return psphotReadoutCleanup (config, view, STACK_SRC);
+    }
+    if (!psphotSetMaskAndVariance (config, view, STACK_OUT)) {
 	return psphotReadoutCleanup (config, view, STACK_SRC);
     }
@@ -151,4 +158,5 @@
     // psphotDumpTest (config, view, STACK_SRC);
     psMemDump("sourcestats");
+    logMemStats("sourcestats");
 
     // classify sources based on moments, brightness
@@ -196,5 +204,7 @@
     // window of size PSF_MOMENTS_RADIUS (same window used to measure the psf-scale moments)
     // but iterates to an appropriately larger size
-    psphotKronIterate(config, view, STACK_SRC);
+    logMemStats("before.kron.1");
+    psphotKronIterate(config, view, STACK_SRC, 1);
+    logMemStats("after.kron.1");
 
     // identify CRs and extended sources
@@ -208,4 +218,5 @@
     psphotReplaceAllSources (config, view, STACK_SRC, false); // pass 1 (detections->allSources)
 
+    logMemStats("pass1");
 
     // if we only do one pass, skip to extended source analysis
@@ -299,4 +310,6 @@
     }
 
+    logMemStats("prematch");
+
     // generate the objects (objects unify the sources from the different images) NOTE: could
     // this just match the detections for the chisq image, and not bother measuring the source
@@ -331,5 +344,7 @@
     // re-measure the kron mags with models subtracted
     // psphotKronMasked(config, view, STACK_SRC);
-    psphotKronIterate(config, view, STACK_SRC);
+    logMemStats("before.kron.2");
+    psphotKronIterate(config, view, STACK_SRC, 2);
+    logMemStats("after.kron.2");
 
     // measure source size for the remaining sources
@@ -353,5 +368,4 @@
 	return psphotReadoutCleanup (config, view, STACK_SRC);
     }
-
 
     bool radial_apertures = psMetadataLookupBool(NULL, recipe, "RADIAL_APERTURES");
@@ -419,5 +433,5 @@
         // psphotEfficiency wants to have the PSF of the image, but since we are measuring on
         // the convolved images we need to generate PSFs for the DET images
-        if (!psphotChoosePSF (config, view, STACK_DET, false)) { // pass 1
+        if (!psphotChoosePSF (config, view, STACK_DET, false)) {
             psLogMsg ("psphot", 3, "failure to construct a psf model for raw input");
             return psphotReadoutCleanup (config, view, STACK_DET);
@@ -429,4 +443,10 @@
     }
     psphotCopyEfficiency (config, view, STACK_OUT, STACK_DET);
+
+    logMemStats("final");
+#if (1)
+    psphotSourceMemory(config, view, STACK_SRC);
+    psphotSourceMemory(config, view, STACK_OUT);
+#endif
 
     // replace failed sources?
@@ -474,4 +494,36 @@
     return true;
 }
+
+// read the memory usage data from /proc and log them out
+// This will only work on a system that has /proc (not MacOS for instance) but since this function just
+// tries to open and read from a file it is safe
+static void logMemStats(const char *heading) {
+
+    // file containing memory statistics for this process proc. See proc(5)
+    const char* statm_path = "/proc/self/statm";
+
+    FILE *f = fopen(statm_path,"r");
+    if (!f) {
+        psLogMsg ("psphot", PS_LOG_WARN, "failed to open %s", statm_path);
+        return;
+    }
+
+    unsigned long vmSize, resident, share, text, lib, data;
+
+    int nread;
+    nread = fscanf(f,"%ld %ld %ld %ld %ld %ld", &vmSize, &resident, &share, &text, &lib, &data);
+    fclose(f);
+    if (nread != 6) {
+        psLogMsg ("psphot", PS_LOG_WARN, "failed to read 6 items from %s", statm_path);
+        return;
+    }
+  
+    // assuming 4 KB page size here
+#   define PAGES_TO_MB(_v) (_v * 4.096 / 1024.)
+    psLogMsg ("psphot", PS_LOG_INFO, "Memory usage at %20s: Total VmSize: %8.2f MB   Resident %8.2f MB   Data: %8.2f MB\n",
+        heading, PAGES_TO_MB(vmSize), PAGES_TO_MB(resident), PAGES_TO_MB(data));
+}
+
+
 
 /* here is the process: