Performance: Remap multiple items in UI

During sprite fright loading of complex scenes would spend a long time in remapping ID's
The remapping process is done on a per ID instance that resulted in a very time consuming
process that goes over every possible ID reference to find out if it needs to be updated.

If there are N of references to ID blocks and there are M ID blocks that needed to be remapped
it would take N*M checks. These checks are scattered around the place and memory.
Each reference would only be updated at most once, but most of the time no update is needed at all.

Idea: By grouping the changes together will reduce the number of checks resulting in improved performance.
This would only require N checks. Additional benefits is improved data locality as data is only loaded once
in the L2 cache.

It has be implemented for the resyncing process and UI editors.
On an Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz 16Gig the resyncing process went
from 170 seconds to 145 seconds (during hotspot recording).

After this patch has been applied we could add similar approach
to references (references between data blocks) and functionality (tagged deletion).
In my understanding this could reduce the resyncing process to less than a second.
Opening the village production file between 10 and 20 seconds.

Flame graphs showing that UI remapping isn't visible anymore (`WM_main_remap_editor_id_reference`)
* Master {F12769210 size=full}
* This patch {F12769211 size=full}

Reviewed By: mont29

Maniphest Tasks: T94185

Differential Revision: https://developer.blender.org/D13615

1 files changed, 56 insertions, 10 deletions

diff --git a/source/blender/blenkernel/intern/lib_remap.c b/source/blender/blenkernel/intern/lib_remap.c
index ec97ca83703..c3ccedb9608 100644
--- a/source/blender/blenkernel/intern/lib_remap.c
+++ b/source/blender/blenkernel/intern/lib_remap.c
@@ -510,11 +510,18 @@ static void libblock_remap_data(
 #endif
 }
 
-void BKE_libblock_remap_locked(Main *bmain, void *old_idv, void *new_idv, const short remap_flags)
+typedef struct LibblockRemapMultipleUserData {
+  Main *bmain;
+  short remap_flags;
+} LibBlockRemapMultipleUserData;
+
+static void libblock_remap_foreach_idpair_cb(ID *old_id, ID *new_id, void *user_data)
 {
+  LibBlockRemapMultipleUserData *data = user_data;
+  Main *bmain = data->bmain;
+  const short remap_flags = data->remap_flags;
+
   IDRemap id_remap_data;
-  ID *old_id = old_idv;
-  ID *new_id = new_idv;
   int skipped_direct, skipped_refcounted;
 
   BLI_assert(old_id != NULL);
@@ -527,13 +534,6 @@ void BKE_libblock_remap_locked(Main *bmain, void *old_idv, void *new_idv, const
     free_notifier_reference_cb(old_id);
   }
 
-  /* We assume editors do not hold references to their IDs... This is false in some cases
-   * (Image is especially tricky here),
-   * editors' code is to handle refcount (id->us) itself then. */
-  if (remap_editor_id_reference_cb) {
-    remap_editor_id_reference_cb(old_id, new_id);
-  }
-
   skipped_direct = id_remap_data.skipped_direct;
   skipped_refcounted = id_remap_data.skipped_refcounted;
 
@@ -606,6 +606,41 @@ void BKE_libblock_remap_locked(Main *bmain, void *old_idv, void *new_idv, const
   DEG_relations_tag_update(bmain);
 }
 
+void BKE_libblock_remap_multiple_locked(Main *bmain,
+                                        const struct IDRemapper *mappings,
+                                        const short remap_flags)
+{
+  if (BKE_id_remapper_is_empty(mappings)) {
+    /* Early exit nothing to do. */
+    return;
+  }
+
+  LibBlockRemapMultipleUserData user_data;
+  user_data.bmain = bmain;
+  user_data.remap_flags = remap_flags;
+  BKE_id_remapper_iter(mappings, libblock_remap_foreach_idpair_cb, &user_data);
+
+  /* We assume editors do not hold references to their IDs... This is false in some cases
+   * (Image is especially tricky here),
+   * editors' code is to handle refcount (id->us) itself then. */
+  if (remap_editor_id_reference_cb) {
+    remap_editor_id_reference_cb(mappings);
+  }
+
+  /* Full rebuild of DEG! */
+  DEG_relations_tag_update(bmain);
+}
+
+void BKE_libblock_remap_locked(Main *bmain, void *old_idv, void *new_idv, const short remap_flags)
+{
+  struct IDRemapper *remapper = BKE_id_remapper_create();
+  ID *old_id = old_idv;
+  ID *new_id = new_idv;
+  BKE_id_remapper_add(remapper, old_id, new_id);
+  BKE_libblock_remap_multiple_locked(bmain, remapper, remap_flags);
+  BKE_id_remapper_free(remapper);
+}
+
 void BKE_libblock_remap(Main *bmain, void *old_idv, void *new_idv, const short remap_flags)
 {
   BKE_main_lock(bmain);
@@ -615,6 +650,17 @@ void BKE_libblock_remap(Main *bmain, void *old_idv, void *new_idv, const short r
   BKE_main_unlock(bmain);
 }
 
+void BKE_libblock_remap_multiple(Main *bmain,
+                                 const struct IDRemapper *mappings,
+                                 const short remap_flags)
+{
+  BKE_main_lock(bmain);
+
+  BKE_libblock_remap_multiple_locked(bmain, mappings, remap_flags);
+
+  BKE_main_unlock(bmain);
+}
+
 void BKE_libblock_unlink(Main *bmain,
                          void *idv,
                          const bool do_flag_never_null,