From 01c481335ad84f8bec29985e982ec0f20aadf522 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Ol=C5=A1=C3=A1k?= <marek.olsak@amd.com>
Date: Tue, 23 Aug 2022 00:12:09 -0400
Subject: [PATCH] glthread: skip glMultMatrixf if it's identity

This is common with viewperf and it helps.

Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18828>
---
 src/mapi/glapi/gen/gl_API.xml    |  3 ++-
 src/mesa/main/glthread_marshal.h | 13 +++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/mapi/glapi/gen/gl_API.xml b/src/mapi/glapi/gen/gl_API.xml
index fc69c152c0b..0d2c9aaf690 100644
--- a/src/mapi/glapi/gen/gl_API.xml
+++ b/src/mapi/glapi/gen/gl_API.xml
@@ -2932,7 +2932,8 @@
         <glx rop="179"/>
     </function>
 
-    <function name="MultMatrixf" es1="1.0" deprecated="3.1" exec="dlist">
+    <function name="MultMatrixf" es1="1.0" deprecated="3.1" exec="dlist"
+              marshal_call_before="if (_mesa_matrix_is_identity(m)) return;">
         <param name="m" type="const GLfloat *" count="16"/>
         <glx rop="180"/>
     </function>
diff --git a/src/mesa/main/glthread_marshal.h b/src/mesa/main/glthread_marshal.h
index f390cb9453c..05dbb106364 100644
--- a/src/mesa/main/glthread_marshal.h
+++ b/src/mesa/main/glthread_marshal.h
@@ -441,6 +441,19 @@ _mesa_get_matrix_index(struct gl_context *ctx, GLenum mode)
    return M_DUMMY;
 }
 
+static inline bool
+_mesa_matrix_is_identity(const float *m)
+{
+   static float identity[16] = {
+      1, 0, 0, 0,
+      0, 1, 0, 0,
+      0, 0, 1, 0,
+      0, 0, 0, 1
+   };
+
+   return !memcmp(m, identity, sizeof(identity));
+}
+
 static inline void
 _mesa_glthread_Enable(struct gl_context *ctx, GLenum cap)
 {