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cache should be threaded

This commit is contained in:
John Cupitt 2013-07-31 22:00:52 +01:00
parent 226095c39d
commit d5cac2a0fe
1 changed files with 12 additions and 0 deletions
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12
tools/vipsthumbnail.c
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@ -342,6 +342,17 @@ thumbnail_shrink( VipsObject *thumbnail, VipsImage *in,
*
* So ... read into a cache where tiles are scanlines, and make sure
* we keep enough scanlines to be able to serve a line of tiles.
*
* We use a threaded tilecache to avoid a deadlock: suppose thread1,
* evaluating the top block of the output, is delayed, and thread2,
* evaluating the second block, gets here first (this can happen on
* a heavily-loaded system).
*
* With an unthreaded tilecache (as we had before), thread2 will get
* the cache lock and start evaling the second block of the shrink.
* When it reaches the png reader it will stall until the first block
* has been used ... but it never will, since thread1 will block on
* this cache lock.
*/
vips_get_tile_size( in,
&tile_width, &tile_height, &nlines );
@ -350,6 +361,7 @@ thumbnail_shrink( VipsObject *thumbnail, VipsImage *in,
"tile_height", 10,
"max_tiles", (nlines * 2) / 10,
"strategy", VIPS_CACHE_SEQUENTIAL,
"threaded", TRUE,
NULL ) ||
vips_affine( t[4], &t[5], residual, 0, 0, residual, NULL,
"interpolate", interp,