mutter/cogl/cogl-pipeline-cache.c
Neil Roberts 5085919acc pipeline-cache: Prune old unused pipelines when the cache gets too big
Previously when a pipeline is added to the cache it would never be
removed. If the application is generating a lot of unique pipelines
this can end up effectively leaking a large number of resources
including the GL program objects. Arguably this isn't really a problem
because if the application is generating that many unique pipelines
then it is doing something wrong anyway. It also implies that it will
be recompiling shaders very often so the cache leaking will likely be
the least of the problems.

This patch makes it keep track of which pipelines in the cache are in
use. The cache now returns a struct representing the entry instead of
directly returning the pipeline. This entry contains a usage counter
which the pipeline backends can use to mark when there is a pipeline
alive that is using the cache entry. When the hash table decides that
it's a good time to prune some entries, it will make a list of all of
the pipelines that are not in use and then remove the least recently
used half of the pipelines. That way it is less likely to remove
pipelines that the application is actually regenerating often even if
they aren't in use all of the time.

When the cache is pruned the hash table makes a note of how small the
cache could be if it removed all of the unused pipelines. The hash
table starts pruning when there are more entries than twice this
minimum expected size. The idea is that if that case it hit then the
hash table is more than half full of useless pipelines so the
application is generating lots of redundant pipelines and it is a good
time to remove them.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit c21aac22992bb7fef5a8d0913130b8245e67f2eb)

Conflicts:
	cogl/driver/gl/cogl-pipeline-fragend-glsl.c
	cogl/driver/gl/cogl-pipeline-progend-glsl.c
	cogl/driver/gl/cogl-pipeline-vertend-glsl.c
	cogl/driver/gl/gl/cogl-pipeline-fragend-arbfp.c
2014-01-14 12:05:17 +00:00

211 lines
7.0 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2011, 2013 Intel Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*
*
* Authors:
* Neil Roberts <neil@linux.intel.com>
* Robert Bragg <robert@linux.intel.com>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <test-fixtures/test-unit.h>
#include "cogl-context-private.h"
#include "cogl-pipeline-private.h"
#include "cogl-pipeline-cache.h"
#include "cogl-pipeline-hash-table.h"
struct _CoglPipelineCache
{
CoglPipelineHashTable fragment_hash;
CoglPipelineHashTable vertex_hash;
CoglPipelineHashTable combined_hash;
};
CoglPipelineCache *
_cogl_pipeline_cache_new (void)
{
CoglPipelineCache *cache = g_new (CoglPipelineCache, 1);
unsigned long vertex_state;
unsigned long layer_vertex_state;
unsigned int fragment_state;
unsigned int layer_fragment_state;
_COGL_GET_CONTEXT (ctx, 0);
vertex_state =
_cogl_pipeline_get_state_for_vertex_codegen (ctx);
layer_vertex_state =
COGL_PIPELINE_LAYER_STATE_AFFECTS_VERTEX_CODEGEN;
fragment_state =
_cogl_pipeline_get_state_for_fragment_codegen (ctx);
layer_fragment_state =
_cogl_pipeline_get_layer_state_for_fragment_codegen (ctx);
_cogl_pipeline_hash_table_init (&cache->vertex_hash,
vertex_state,
layer_vertex_state,
"vertex shaders");
_cogl_pipeline_hash_table_init (&cache->fragment_hash,
fragment_state,
layer_fragment_state,
"fragment shaders");
_cogl_pipeline_hash_table_init (&cache->combined_hash,
vertex_state | fragment_state,
layer_vertex_state | layer_fragment_state,
"programs");
return cache;
}
void
_cogl_pipeline_cache_free (CoglPipelineCache *cache)
{
_cogl_pipeline_hash_table_destroy (&cache->fragment_hash);
_cogl_pipeline_hash_table_destroy (&cache->vertex_hash);
_cogl_pipeline_hash_table_destroy (&cache->combined_hash);
g_free (cache);
}
CoglPipelineCacheEntry *
_cogl_pipeline_cache_get_fragment_template (CoglPipelineCache *cache,
CoglPipeline *key_pipeline)
{
return _cogl_pipeline_hash_table_get (&cache->fragment_hash,
key_pipeline);
}
CoglPipelineCacheEntry *
_cogl_pipeline_cache_get_vertex_template (CoglPipelineCache *cache,
CoglPipeline *key_pipeline)
{
return _cogl_pipeline_hash_table_get (&cache->vertex_hash,
key_pipeline);
}
CoglPipelineCacheEntry *
_cogl_pipeline_cache_get_combined_template (CoglPipelineCache *cache,
CoglPipeline *key_pipeline)
{
return _cogl_pipeline_hash_table_get (&cache->combined_hash,
key_pipeline);
}
#ifdef ENABLE_UNIT_TESTS
static void
create_pipelines (CoglPipeline **pipelines,
int n_pipelines)
{
int i;
for (i = 0; i < n_pipelines; i++)
{
char *source = g_strdup_printf (" cogl_color_out = "
"vec4 (%f, 0.0, 0.0, 1.0);\n",
i / 255.0f);
CoglSnippet *snippet =
cogl_snippet_new (COGL_SNIPPET_HOOK_FRAGMENT,
NULL, /* declarations */
source);
g_free (source);
pipelines[i] = cogl_pipeline_new (test_ctx);
cogl_pipeline_add_snippet (pipelines[i], snippet);
cogl_object_unref (snippet);
}
/* Test that drawing with them works. This should create the entries
* in the cache */
for (i = 0; i < n_pipelines; i++)
{
cogl_framebuffer_draw_rectangle (test_fb,
pipelines[i],
i, 0,
i + 1, 1);
test_utils_check_pixel_rgb (test_fb, i, 0, i, 0, 0);
}
}
UNIT_TEST (check_pipeline_pruning,
TEST_REQUIREMENT_GLSL, /* requirements */
0 /* no failure cases */)
{
CoglPipeline *pipelines[18];
int fb_width, fb_height;
CoglPipelineHashTable *fragment_hash =
&test_ctx->pipeline_cache->fragment_hash;
CoglPipelineHashTable *combined_hash =
&test_ctx->pipeline_cache->combined_hash;
int i;
fb_width = cogl_framebuffer_get_width (test_fb);
fb_height = cogl_framebuffer_get_height (test_fb);
cogl_framebuffer_orthographic (test_fb,
0, 0,
fb_width,
fb_height,
-1,
100);
/* Create 18 unique pipelines. This should end up being more than
* the initial expected minimum size so it will trigger the garbage
* collection. However all of the pipelines will be in use so they
* won't be collected */
create_pipelines (pipelines, 18);
/* These pipelines should all have unique entries in the cache. We
* should have run the garbage collection once and at that point the
* expected minimum size would have been 17 */
g_assert_cmpint (g_hash_table_size (fragment_hash->table), ==, 18);
g_assert_cmpint (g_hash_table_size (combined_hash->table), ==, 18);
g_assert_cmpint (fragment_hash->expected_min_size, ==, 17);
g_assert_cmpint (combined_hash->expected_min_size, ==, 17);
/* Destroy the original pipelines and create some new ones. This
* should run the garbage collector again but this time the
* pipelines won't be in use so it should free some of them */
for (i = 0; i < 18; i++)
cogl_object_unref (pipelines[i]);
create_pipelines (pipelines, 18);
/* The garbage collection should have freed half of the original 18
* pipelines which means there should now be 18*1.5 = 27 */
g_assert_cmpint (g_hash_table_size (fragment_hash->table), ==, 27);
g_assert_cmpint (g_hash_table_size (combined_hash->table), ==, 27);
/* The 35th pipeline would have caused the garbage collection. At
* that point there would be 35-18=17 used unique pipelines. */
g_assert_cmpint (fragment_hash->expected_min_size, ==, 17);
g_assert_cmpint (combined_hash->expected_min_size, ==, 17);
for (i = 0; i < 18; i++)
cogl_object_unref (pipelines[i]);
}
#endif /* ENABLE_UNIT_TESTS */