Update performance optimization pages for Godot 4.x

Author: Calinou

tutorials/performance/cpu_optimization.rst

@@ -1,12 +1,10 @@
-:article_outdated: True
-
 .. _doc_cpu_optimization:
 
 CPU optimization
 ================
 
 Measuring performance
-=====================
+---------------------
 
 We have to know where the "bottlenecks" are to know how to speed up our program.
 Bottlenecks are the slowest parts of the program that limit the rate that
@@ -18,7 +16,7 @@ lead to small performance improvements.
 For the CPU, the easiest way to identify bottlenecks is to use a profiler.
 
 CPU profilers
-=============
+-------------
 
 Profilers run alongside your program and take timing measurements to work out
 what proportion of time is spent in each function.
@@ -31,7 +29,7 @@ slow down your project significantly.
 After profiling, you can look back at the results for a frame.
 
 .. figure:: img/godot_profiler.png
-.. figure:: img/godot_profiler.png
+   :align: center
    :alt: Screenshot of the Godot profiler
 
    Results of a profile of one of the demo projects.
@@ -51,7 +49,7 @@ For more info about using Godot's built-in profiler, see
 :ref:`doc_debugger_panel`.
 
 External profilers
-~~~~~~~~~~~~~~~~~~
+------------------
 
 Although the Godot IDE profiler is very convenient and useful, sometimes you
 need more power, and the ability to profile the Godot engine source code itself.
@@ -98,7 +96,7 @@ batching, which greatly speeds up 2D rendering by reducing bottlenecks in this
 area.
 
 Manually timing functions
-=========================
+-------------------------
 
 Another handy technique, especially once you have identified the bottleneck
 using a profiler, is to manually time the function or area under test.
@@ -126,7 +124,7 @@ time them as you go. This will give you crucial feedback as to whether the
 optimization is working (or not).
 
 Caches
-======
+------
 
 CPU caches are something else to be particularly aware of, especially when
 comparing timing results of two different versions of a function. The results
@@ -159,7 +157,7 @@ rendering and physics. Still, you should be especially aware of caching when
 writing GDExtensions.
 
 Languages
-=========
+---------
 
 Godot supports a number of different languages, and it is worth bearing in mind
 that there are trade-offs involved. Some languages are designed for ease of use
@@ -170,7 +168,7 @@ language you choose. If your project is making a lot of calculations in its own
 code, consider moving those calculations to a faster language.
 
 GDScript
-~~~~~~~~
+^^^^^^^^
 
 :ref:`GDScript <toc-learn-scripting-gdscript>` is designed to be easy to use and iterate,
 and is ideal for making many types of games. However, in this language, ease of
@@ -179,7 +177,7 @@ calculations, consider moving some of your project to one of the other
 languages.
 
 C#
-~~
+^^
 
 :ref:`C# <toc-learn-scripting-C#>` is popular and has first-class support in Godot. It
 offers a good compromise between speed and ease of use. Beware of possible
@@ -188,13 +186,13 @@ common approach to workaround issues with garbage collection is to use *object
 pooling*, which is outside the scope of this guide.
 
 Other languages
-~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^
 
 Third parties provide support for several other languages, including `Rust
 <https://github.com/godot-rust/gdext>`_.
 
 C++
-~~~
+^^^
 
 Godot is written in C++. Using C++ will usually result in the fastest code.
 However, on a practical level, it is the most difficult to deploy to end users'
@@ -203,7 +201,7 @@ GDExtensions and
 :ref:`custom modules <doc_custom_modules_in_cpp>`.
 
 Threads
-=======
+-------
 
 Consider using threads when making a lot of calculations that can run in
 parallel to each other. Modern CPUs have multiple cores, each one capable of
@@ -222,7 +220,7 @@ debugger doesn't support setting up breakpoints in threads yet.
 For more information on threads, see :ref:`doc_using_multiple_threads`.
 
 SceneTree
-=========
+---------
 
 Although Nodes are an incredibly powerful and versatile concept, be aware that
 every node has a cost. Built-in functions such as `_process()` and
@@ -247,7 +245,7 @@ You can avoid the SceneTree altogether by using Server APIs. For more
 information, see :ref:`doc_using_servers`.
 
 Physics
-=======
+-------
 
 In some situations, physics can end up becoming a bottleneck. This is
 particularly the case with complex worlds and large numbers of physics objects.

tutorials/performance/general_optimization.rst

@@ -1,12 +1,10 @@
-:article_outdated: True
-
 .. _doc_general_optimization:
 
 General optimization tips
 =========================
 
 Introduction
-~~~~~~~~~~~~
+------------
 
 In an ideal world, computers would run at infinite speed. The only limit to
 what we could achieve would be our imagination. However, in the real world, it's
@@ -48,7 +46,7 @@ But in reality, there are several different kinds of performance problems:
 Each of these are annoying to the user, but in different ways.
 
 Measuring performance
-=====================
+---------------------
 
 Probably the most important tool for optimization is the ability to measure
 performance - to identify where bottlenecks are, and to measure the success of
@@ -57,19 +55,24 @@ our attempts to speed them up.
 There are several methods of measuring performance, including:
 
 - Putting a start/stop timer around code of interest.
-- Using the Godot profiler.
-- Using external third-party CPU profilers.
-- Using GPU profilers/debuggers such as
-  `NVIDIA Nsight Graphics <https://developer.nvidia.com/nsight-graphics>`__
-  or `apitrace <https://apitrace.github.io/>`__.
-- Checking the frame rate (with V-Sync disabled).
+- Using the :ref:`Godot profiler <doc_the_profiler>`.
+- Using :ref:`external CPU profilers <doc_using_cpp_profilers>`.
+- Using external GPU profilers/debuggers such as
+  `NVIDIA Nsight Graphics <https://developer.nvidia.com/nsight-graphics>`__,
+  `Radeon GPU Profiler <https://gpuopen.com/rgp/>`__ or
+  `Intel Graphics Performance Analyzers <https://www.intel.com/content/www/us/en/developer/tools/graphics-performance-analyzers/overview.html>`__.
+- Checking the frame rate (with V-Sync disabled). Third-party utilities such as
+  `RivaTuner Statistics Server <https://www.guru3d.com/files-details/rtss-rivatuner-statistics-server-download.html>`__
+  (Windows) or `MangoHud <https://github.com/flightlessmango/MangoHud>`__
+  (Linux) can also be useful here.
+- Using an unofficial `debug menu add-on <https://github.com/godot-extended-libraries/godot-debug-menu>`.
 
 Be very aware that the relative performance of different areas can vary on
 different hardware. It's often a good idea to measure timings on more than one
 device. This is especially the case if you're targeting mobile devices.
 
 Limitations
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 CPU profilers are often the go-to method for measuring performance. However,
 they don't always tell the whole story.
@@ -87,7 +90,7 @@ As a result of these limitations, you often need to use detective work to find
 out where bottlenecks are.
 
 Detective work
-~~~~~~~~~~~~~~
+--------------
 
 Detective work is a crucial skill for developers (both in terms of performance,
 and also in terms of bug fixing). This can include hypothesis testing, and
@@ -119,7 +122,7 @@ Once you know which of the two halves contains the bottleneck, you can
 repeat this process until you've pinned down the problematic area.
 
 Profilers
-=========
+---------
 
 Profilers allow you to time your program while running it. Profilers then
 provide results telling you what percentage of time was spent in different
@@ -133,7 +136,7 @@ and lead to slower performance.
 For more info about using Godot's built-in profiler, see :ref:`doc_the_profiler`.
 
 Principles
-==========
+----------
 
 `Donald Knuth <https://en.wikipedia.org/wiki/Donald_Knuth>`__ said:
 
@@ -163,7 +166,7 @@ optimization is (by definition) undesirable, performant software is the result
 of performant design.
 
 Performant design
-~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^
 
 The danger with encouraging people to ignore optimization until necessary, is
 that it conveniently ignores that the most important time to consider
@@ -178,7 +181,7 @@ will often run many times faster than a mediocre design with low-level
 optimization.
 
 Incremental design
-~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^
 
 Of course, in practice, unless you have prior knowledge, you are unlikely to
 come up with the best design the first time. Instead, you'll often make a series
@@ -195,7 +198,7 @@ structures and algorithms for *cache locality* of data and linear access, rather
 than jumping around in memory.
 
 The optimization process
-~~~~~~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^^^^^^
 
 Assuming we have a reasonable design, and taking our lessons from Knuth, our
 first step in optimization should be to identify the biggest bottlenecks - the
@@ -212,7 +215,7 @@ The process is thus:
 3. Return to step 1.
 
 Optimizing bottlenecks
-~~~~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^^^^
 
 Some profilers will even tell you which part of a function (which data accesses,
 calculations) are slowing things down.
@@ -237,10 +240,10 @@ positive effect will be outweighed by the negatives of more complex code, and
 you may choose to leave out that optimization.
 
 Appendix
-========
+--------
 
 Bottleneck math
-~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^
 
 The proverb *"a chain is only as strong as its weakest link"* applies directly to
 performance optimization. If your project is spending 90% of the time in