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%.

diff --git a/src/mesa/main/texobj.c b/src/mesa/main/texobj.c
index d51e7b76ec7594faf921c1d85b5848bcddf77bb6..2082f945f1852d0132f477346fe44ddbc9d1d17b 100644 (file)
--- a/src/mesa/main/texobj.c
+++ b/src/mesa/main/texobj.c
@@ -945,6 +945,7 @@ _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))
@@ -998,6 +999,17 @@ _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);