commit 361fb38662f80e645e9087781faa4bec10dd6ac7
author Icecream95 <ixn@keemail.me> Sat Jun 20 19:30:54 2020 +1200
committer Marge Bot <eric+marge@anholt.net> Mon Jun 22 12:15:05 2020 +0000
tree f66f139677eebbb0e7ab8034f5b95718f4e44e50
parent 65b3b08aaf4f5e9d9207e174232b4bbb820d7de4

panfrost: Copy resources when mapping to avoid waiting for readers

It is often faster to copy the whole resource and modify that than
to flush and wait for readers of the BO.

Helps anything which updates textures after already using them in a
frame, such as most GLQuake ports.

Reviewed-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5573>

src/gallium/drivers/panfrost/pan_resource.c

diff --git a/src/gallium/drivers/panfrost/pan_resource.c b/src/gallium/drivers/panfrost/pan_resource.c
index 8c1cda9..9d1905d 100644
--- a/src/gallium/drivers/panfrost/pan_resource.c
+++ b/src/gallium/drivers/panfrost/pan_resource.c
@@ -597,7 +597,26 @@
         if (pan_debug & (PAN_DBG_TRACE | PAN_DBG_SYNC))
                 pandecode_inject_mmap(bo->gpu, bo->cpu, bo->size, NULL);
 
-        if (usage & PIPE_TRANSFER_DISCARD_WHOLE_RESOURCE) {
+        bool create_new_bo = usage & PIPE_TRANSFER_DISCARD_WHOLE_RESOURCE;
+        bool copy_resource = false;
+
+        if (!create_new_bo &&
+            !(usage & PIPE_TRANSFER_UNSYNCHRONIZED) &&
+            (usage & PIPE_TRANSFER_WRITE) &&
+            !(resource->target == PIPE_BUFFER
+              && !util_ranges_intersect(&rsrc->valid_buffer_range, box->x, box->x + box->width))) {
+
+                /* It is often faster to copy the whole resource than to flush
+                 * readers */
+
+                panfrost_flush_batches_accessing_bo(ctx, bo, PAN_BO_ACCESS_WRITE);
+                panfrost_bo_wait(bo, INT64_MAX, PAN_BO_ACCESS_WRITE);
+
+                create_new_bo = true;
+                copy_resource = true;
+        }
+
+        if (create_new_bo) {
                 /* If the BO is used by one of the pending batches or if it's
                  * not ready yet (still accessed by one of the already flushed
                  * batches), we try to allocate a new one to avoid waiting.
@@ -619,6 +638,9 @@
                                                            flags);
 
                         if (newbo) {
+                                if (copy_resource)
+                                        memcpy(newbo->cpu, rsrc->bo->cpu, bo->size);
+
                                 panfrost_bo_unreference(bo);
                                 rsrc->bo = newbo;
                                 bo = newbo;