gl: Do less work on glyph caching

There is no need for us to be very precise about
aging the glyph entries. It is enough to check
occasionally and mark old entries. This reduces
the overhead of work we do every frame on the
caches, at the cost of letting glyphs linger
a bit longer in the cache.
This commit is contained in:
Matthias Clasen 2019-10-12 11:03:04 -04:00
parent bcdc3b706c
commit 977ac2b31f
2 changed files with 20 additions and 19 deletions

View File

@ -15,9 +15,9 @@
/* Cache eviction strategy
*
* Each cached glyph has an age that gets reset every time a cached
* glyph gets used. Glyphs that have not been used for the
* MAX_FRAME_AGE frames are considered old.
* We mark glyphs as accessed every time we use them. Every
* few frames, we mark glyphs that haven't been accessed since
* the last check as old.
*
* We keep count of the pixels of each atlas that are taken up by old
* data. When the fraction of old pixels gets too high, we drop the
@ -264,12 +264,12 @@ gsk_gl_glyph_cache_lookup_or_add (GskGLGlyphCache *cache,
if (value)
{
value->timestamp = cache->timestamp;
if (value->atlas && !value->used)
{
gsk_gl_texture_atlas_mark_used (value->atlas, value->draw_width, value->draw_height);
value->used = TRUE;
}
value->accessed = TRUE;
*cached_glyph_out = value;
return;
@ -292,7 +292,7 @@ gsk_gl_glyph_cache_lookup_or_add (GskGLGlyphCache *cache,
value->draw_y = ink_rect.y;
value->draw_width = ink_rect.width;
value->draw_height = ink_rect.height;
value->timestamp = cache->timestamp;
value->accessed = TRUE;
value->atlas = NULL; /* For now */
key = g_new0 (GlyphCacheKey, 1);
@ -341,20 +341,21 @@ gsk_gl_glyph_cache_begin_frame (GskGLGlyphCache *self,
GSK_NOTE(GLYPH_CACHE, if (dropped > 0) g_message ("Dropped %d glyphs", dropped));
}
g_hash_table_iter_init (&iter, self->hash_table);
while (g_hash_table_iter_next (&iter, (gpointer *)&key, (gpointer *)&value))
if (self->timestamp % MAX_FRAME_AGE == 0)
{
const guint age = self->timestamp - value->timestamp;
if (age > MAX_FRAME_AGE)
g_hash_table_iter_init (&iter, self->hash_table);
while (g_hash_table_iter_next (&iter, (gpointer *)&key, (gpointer *)&value))
{
GskGLTextureAtlas *atlas = value->atlas;
if (atlas && value->used)
if (!value->accessed)
{
gsk_gl_texture_atlas_mark_unused (atlas, value->draw_width, value->draw_height);
value->used = FALSE;
if (value->atlas && value->used)
{
gsk_gl_texture_atlas_mark_unused (value->atlas, value->draw_width, value->draw_height);
value->used = FALSE;
}
}
}
value->accessed = FALSE;
}
}
}

View File

@ -15,7 +15,7 @@ typedef struct
GHashTable *hash_table;
GskGLTextureAtlases *atlases;
guint64 timestamp;
int timestamp;
} GskGLGlyphCache;
typedef struct
@ -63,8 +63,8 @@ struct _GskGLCachedGlyph
int draw_width;
int draw_height;
guint used: 1;
guint64 timestamp;
guint accessed : 1; /* accessed since last check */
guint used : 1; /* accounted as used in the atlas */
};