add VIPS_COUNT_PIXELS, overcomputation tracking

added VIPS_COUNT_PIXELS(), use like this:

	static int vips_shrinkh_gen( VipsRegion *or, ... )
	{
        	VIPS_COUNT_PIXELS( or, "vips_shrinkh_gen" );
	}

and on image close, if more than 100% of the pixels have been
calculated, you get a warning

only if you enable debugging, since this hurts perf slightly

ChangeLog

@@ -19,6 +19,7 @@
 - python .bandrank() now works like .bandjoin()
 - vipsthumbnail --interpolator and --sharpen switches are deprecated
 - switches to disable PPM, Rad and Analyze support
+- added VIPS_COUNT_PIXELS(), overcomputation tracking
 
 27/1/16 started 8.2.3
 - fix a crash with SPARC byte-order labq vips images

TODO

@@ -1,7 +1,3 @@
-- could instrument vips_region_prepare() and track number of pixels calculated
-  for each image ... on image close (or evelend?) print %computed, values over
-  100% would indicate overcomputation
-
 - if we do 
 
 	vips_region_prepare( VipsRect { 0, 0, 100, 10 } )
@@ -10,6 +6,23 @@
   do we recalculate the whole region, or shift the calculated bits down and
   just fetch another line?
 
+  how would we calculate a small part of a region?
+
+  vips_region_fill() would need to do this
+
+  instrument a bit and see what kinds of buffers we are seeing
+
+  if we see 
+
+	buffer.done: true
+	buffer.area: {0, 0, 100, 10 }
+
+  and we are asked for 
+
+	buffer.area: {0, 1, 100, 10 }
+
+  we can scroll, then use vips_region_prepare_to() to calculate just the 
+  new pixels ... would this fix it?
 
 
 

libvips/include/vips/internal.h

@@ -233,6 +233,19 @@ char *vips__make_xml_metadata( const char *domain, VipsImage *image );
 
 void vips__cairo2rgba( guint32 *buf, int n );
 
+#ifdef DEBUG_LEAK
+extern GQuark vips__image_pixels_quark;
+#endif /*DEBUG_LEAK*/
+
+/* With DEBUG_LEAK, hang one of these off each image and count pixels 
+ * calculated.
+ */
+typedef struct _VipsImagePixels {
+	const char *nickname; 
+	gint64 tpels;		/* Number of pels we expect to calculate */
+	gint64 npels;		/* Number of pels calculated so far */
+} VipsImagePixels;
+
 #ifdef __cplusplus
 }
 #endif /*__cplusplus*/

libvips/include/vips/region.h

@@ -125,6 +125,19 @@ void vips_region_invalidate( VipsRegion *reg );
 
 void vips_region_dump_all( void );
 
+#ifdef DEBUG_LEAK
+void vips__region_count_pixels( VipsRegion *region, const char *nickname );
+#endif /*DEBUG_LEAK*/
+
+/* Use this to count pixels passing through key points. Handy for spotting bad
+ * overcomputation.
+ */
+#ifdef DEBUG_LEAK
+#define VIPS_COUNT_PIXELS( R, N ) vips__region_count_pixels( R, N )
+#else /*!DEBUG_LEAK*/
+#define VIPS_COUNT_PIXELS( R, N ) 
+#endif /*DEBUG_LEAK*/
+
 /* Macros on VipsRegion.
  *	VIPS_REGION_LSKIP()		add to move down line
  *	VIPS_REGION_N_ELEMENTS()	number of elements across region

libvips/iofuncs/image.c

@@ -480,6 +480,22 @@ vips_image_dispose( GObject *gobject )
 
 	VIPS_DEBUG_MSG( "vips_image_dispose: %p\n", gobject );
 
+#ifdef DEBUG_LEAK
+{
+	VipsImagePixels *pixels = g_object_get_qdata( G_OBJECT( image ), 
+		vips__image_pixels_quark ); 
+
+	if( pixels &&
+		pixels->tpels ) {
+		int compute_percent = 100.0 * pixels->npels / pixels->tpels;
+
+		if( compute_percent > 100 ) 
+			printf( "vips_image_dispose: %s computed %d%%\n", 
+				pixels->nickname, compute_percent );
+	}
+}
+#endif /*DEBUG_LEAK*/
+
 	vips_object_preclose( VIPS_OBJECT( gobject ) );
 
 	/* We have to junk the fd in dispose, since we run this for rewind and
@@ -1368,6 +1384,11 @@ vips_image_init( VipsImage *image )
 	image->sizeof_header = VIPS_SIZEOF_HEADER;
 
 	image->mode = g_strdup( "p" );
+
+#ifdef DEBUG_LEAK
+	g_object_set_qdata_full( G_OBJECT( image ), vips__image_pixels_quark, 
+		g_new0( VipsImagePixels, 1 ), (GDestroyNotify) g_free ); 
+#endif /*DEBUG_LEAK*/
 }
 
 int

libvips/iofuncs/init.c

@@ -102,6 +102,12 @@ static char *vips__argv0 = NULL;
  */
 int vips__leak = 0;
 
+#ifdef DEBUG_LEAK
+/* Count pixels processed per image here.
+ */
+GQuark vips__image_pixels_quark = 0; 
+#endif /*DEBUG_LEAK*/
+
 /**
  * vips_get_argv0:
  *
@@ -394,6 +400,11 @@ vips_init( const char *argv0 )
 	atexit( vips_shutdown );
 #endif /*HAVE_ATEXIT*/
 
+#ifdef DEBUG_LEAK
+	vips__image_pixels_quark = 
+		g_quark_from_static_string( "vips-image-pixels" ); 
+#endif /*DEBUG_LEAK*/
+
 	done = TRUE;
 
 	vips__thread_gate_stop( "init: startup" ); 

libvips/iofuncs/region.c

@@ -1631,3 +1631,21 @@ vips_region_dump_all( void )
 	g_mutex_unlock( vips__global_lock );
 }
 #endif /*VIPS_DEBUG*/
+
+#ifdef DEBUG_LEAK
+void
+vips__region_count_pixels( VipsRegion *region, const char *nickname )
+{
+	VipsImage *image = region->im;
+	VipsImagePixels *pixels = g_object_get_qdata( G_OBJECT( image ), 
+		vips__image_pixels_quark ); 
+
+	g_mutex_lock( vips__global_lock );
+	if( !pixels->tpels )
+		pixels->tpels = VIPS_IMAGE_N_PELS( image ); 
+	if( !pixels->nickname )
+		pixels->nickname = nickname; 
+	pixels->npels += region->valid.width * region->valid.height;
+	g_mutex_unlock( vips__global_lock );
+}
+#endif /*DEBUG_LEAK*/

libvips/resample/affine.c

@@ -367,6 +367,8 @@ vips_affine_gen( VipsRegion *or, void *seq, void *a, void *b, gboolean *stop )
 
 	VIPS_GATE_STOP( "vips_affine_gen: work" ); 
 
+	VIPS_COUNT_PIXELS( or, "vips_affine_gen" ); 
+
 	return( 0 );
 }
 

libvips/resample/reduceh.cpp

@@ -399,6 +399,8 @@ vips_reduceh_gen( VipsRegion *out_region, void *seq,
 
 	VIPS_GATE_STOP( "vips_reduceh_gen: work" ); 
 
+	VIPS_COUNT_PIXELS( out_region, "vips_reduceh_gen" ); 
+
 	return( 0 );
 }
 

libvips/resample/reducev.cpp

@@ -591,6 +591,8 @@ vips_reducev_gen( VipsRegion *out_region, void *vseq,
 
 	VIPS_GATE_STOP( "vips_reducev_gen: work" ); 
 
+	VIPS_COUNT_PIXELS( out_region, "vips_reducev_gen" ); 
+
 	return( 0 );
 }
 
@@ -666,6 +668,8 @@ vips_reducev_vector_gen( VipsRegion *out_region, void *vseq,
 
 	VIPS_GATE_STOP( "vips_reducev_vector_gen: work" ); 
 
+	VIPS_COUNT_PIXELS( out_region, "vips_reducev_vector_gen" ); 
+
 	return( 0 );
 }
 

libvips/resample/shrinkh.c

@@ -218,6 +218,8 @@ vips_shrinkh_gen( VipsRegion *or, void *seq,
 		VIPS_GATE_STOP( "vips_shrinkh_gen: work" ); 
 	}
 
+	VIPS_COUNT_PIXELS( or, "vips_shrinkh_gen" ); 
+
 	return( 0 );
 }
 

libvips/resample/shrinkv.c

@@ -316,6 +316,8 @@ vips_shrinkv_gen( VipsRegion *or, void *vseq,
 		VIPS_GATE_STOP( "vips_shrinkv_gen: work" ); 
 	}
 
+	VIPS_COUNT_PIXELS( or, "vips_shrinkv_gen" ); 
+
 	return( 0 );
 }