From 09774740a7702e86a35448c9c1941440fe80548a Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Wed, 22 Feb 2017 20:11:52 +0000
Subject: [PATCH] better cache sizing

---
 TODO                           | 17 -----------------
 libvips/conversion/tilecache.c |  2 +-
 libvips/iofuncs/sink.c         | 35 +++++++++++++++++++++++++++++++++-
 libvips/iofuncs/sinkdisc.c     |  5 +++++
 4 files changed, 40 insertions(+), 19 deletions(-)

diff --git a/TODO b/TODO
index 88b621f3..40c1ca70 100644
--- a/TODO
+++ b/TODO
@@ -1,20 +1,3 @@
-- seq no longer stalls ahead threads ... instead, we rely on sinkdisk 
-  interlocks to limit how far ahead or behind threads can get
-
-  reexamine cache sizing ... are they too large?
-
-  is thumbnail thinstrip or fatstrip? how does that affect seq cache sizing?
-
-  add something to linecache (and tilecache?) to get it to display cache size
-
-  sinkdisk could use a smaller wbuffer for thinstrip .. thinstrip * nthreads high
-  ... this would reduce the size of the input caches we need during shrink
-
-  same for fatstrip ... would it be less than tile-height? 
-
-
-
-
 - vips linecache has access there twice!
 
 	 $ vips linecache
diff --git a/libvips/conversion/tilecache.c b/libvips/conversion/tilecache.c
index 14808159..e280961e 100644
--- a/libvips/conversion/tilecache.c
+++ b/libvips/conversion/tilecache.c
@@ -382,7 +382,7 @@ vips_block_cache_build( VipsObject *object )
 		build( object ) )
 		return( -1 );
 
-	VIPS_DEBUG_MSG( "vips_block_cache_build: max size = %g MB\n",
+	g_info( "vips_block_cache_build: max size = %g MB",
 		(cache->max_tiles * cache->tile_width * cache->tile_height *
 		 	VIPS_IMAGE_SIZEOF_PEL( cache->in )) / (1024 * 1024.0) );
 
diff --git a/libvips/iofuncs/sink.c b/libvips/iofuncs/sink.c
index e950ffdf..14371ee3 100644
--- a/libvips/iofuncs/sink.c
+++ b/libvips/iofuncs/sink.c
@@ -200,6 +200,9 @@ sink_free( Sink *sink )
 void
 vips_sink_base_init( SinkBase *sink_base, VipsImage *image )
 {
+	int tiles_across;
+	int tiles_down;
+
 	/* Always clear kill before we start looping. See the 
 	 * call to vips_image_iskilled() below.
 	 */
@@ -208,12 +211,42 @@ vips_sink_base_init( SinkBase *sink_base, VipsImage *image )
 	sink_base->im = image;
 	sink_base->x = 0;
 	sink_base->y = 0;
+	sink_base->processed = 0;
 
 	vips_get_tile_size( image, 
 		&sink_base->tile_width, &sink_base->tile_height, 
 		&sink_base->nlines );
 
-	sink_base->processed = 0;
+	/* vips_get_tile_size() is very conservative about setting nlines. We
+	 * know that we are the final element in the pipeline, so we can be
+	 * much tighter.
+	 */
+
+	/* Number of tiles we need across to fill the image width. This will be
+	 * 1 for fat/thin strip.
+	 */
+	tiles_across = 
+		VIPS_ROUND_UP( image->Xsize, sink_base->tile_width ) / 
+		sink_base->tile_width;
+
+	/* Number of rows of tiles we need to have at least 1 tile per thread.
+	 */
+	tiles_down = 
+		VIPS_ROUND_UP( vips_concurrency_get(), tiles_across ) / 
+		tiles_across; 
+
+	/* Therefore the number of scanlines to have at least one tile per
+	 * thread in a buffer.
+	 */
+	sink_base->nlines = tiles_down * sink_base->tile_height;
+
+	g_info( _( "%s %s: %d x %d pixels, %d threads, %d x %d tiles, "
+		"%d lines in buffer" ),
+		g_get_prgname(), image->filename,
+		image->Xsize, image->Ysize,
+		vips_concurrency_get(),
+		sink_base->tile_width, sink_base->tile_height, 
+		sink_base->nlines );
 }
 
 static int
diff --git a/libvips/iofuncs/sinkdisc.c b/libvips/iofuncs/sinkdisc.c
index 30f2134b..36483ae3 100644
--- a/libvips/iofuncs/sinkdisc.c
+++ b/libvips/iofuncs/sinkdisc.c
@@ -238,6 +238,11 @@ wbuffer_new( Write *write )
 		return( NULL );
 	}
 
+	g_info( "wbuffer_new: %g MB",
+		(write->sink_base.nlines * 
+		 	VIPS_IMAGE_SIZEOF_LINE( write->sink_base.im )) /
+		(1024 * 1024.0) );
+
 	return( wbuffer );
 }