Fast path when rebinding the same texture in single context environment

If there is no shared context, there is no purpose in rebinding the same
texture.  In some artificial tests this improves performance 10% - 30%.
(cherry picked from commit 7f8000db8bd45bb95bda4a4f8535c49b8ef74254)

diff --git a/src/mesa/main/texobj.c b/src/mesa/main/texobj.c
index b63f747fe8d3936cd2b5e40e246ac77e524d3fcb..9b8d3777fb100c7ac0d0a580dccefc0290ed43e1 100644 (file)
--- a/src/mesa/main/texobj.c
+++ b/src/mesa/main/texobj.c
@@ -891,6 +891,7 @@ _mesa_BindTexture( GLenum target, GLuint texName )
    struct gl_texture_unit *texUnit = &ctx->Texture.Unit[unit];
    struct gl_texture_object *newTexObj = NULL, *defaultTexObj = NULL;
    GLint targetIndex;
+   GLboolean early_out = GL_FALSE;
    ASSERT_OUTSIDE_BEGIN_END(ctx);
 
    if (MESA_VERBOSE & (VERBOSE_API|VERBOSE_TEXTURE))
@@ -944,6 +945,17 @@ _mesa_BindTexture( GLenum target, GLuint texName )
 
    assert(valid_texture_object(newTexObj));
 
+   _glthread_LOCK_MUTEX(ctx->Shared->Mutex);
+   if ((ctx->Shared->RefCount == 1)
+       && (newTexObj == texUnit->CurrentTex[targetIndex])) {
+      early_out = GL_TRUE;
+   }
+   _glthread_UNLOCK_MUTEX(ctx->Shared->Mutex);
+
+   if (early_out) {
+      return;
+   }
+
    /* flush before changing binding */
    FLUSH_VERTICES(ctx, _NEW_TEXTURE);