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authorAnthony Liguori <aliguori@us.ibm.com>2013-05-13 15:22:24 -0500
committerAnthony Liguori <aliguori@us.ibm.com>2013-05-13 15:27:18 -0500
commit035873283b3f7514ad77d409870ccfd5f9680d9e (patch)
treec7b21f32c53e37dc7da2030debe1ecbaae98384a /include/qom
parentb087143b4d010451208264b7c841436aafe1cbb1 (diff)
qom: aggressively optimize qom casting
This patch adds a small typename cache to ObjectClass. This allows caching positive casts within each ObjectClass. Benchmarking a PPC workload provided by Aurelien, this patch eliminates every single g_hash_table_lookup() happening during the benchmark (which was about 2 million per-second). With this patch applied, I get exactly the same performance (within the margin of error) as with --disable-qom-cast-debug. N.B. it's safe to cache typenames only from the _assert() macros because they are always called with string literals. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'include/qom')
-rw-r--r--include/qom/object.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/qom/object.h b/include/qom/object.h
index 63e2a404da..23fc048088 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -344,6 +344,8 @@ typedef void (ObjectUnparent)(Object *obj);
*/
typedef void (ObjectFree)(void *obj);
+#define OBJECT_CLASS_CAST_CACHE 4
+
/**
* ObjectClass:
*
@@ -356,6 +358,8 @@ struct ObjectClass
Type type;
GSList *interfaces;
+ const char *cast_cache[OBJECT_CLASS_CAST_CACHE];
+
ObjectUnparent *unparent;
};