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@@ -6,14 +6,13 @@ The Profiler
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You run your game from Godot and play around. It's fun, it's becoming feature
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complete, and you feel it's getting close to release.
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-But then, you open the skill tree, and it grinds to a halt as something snags
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-in your code. Watching the skill tree scroll by like it's a slide show is
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+But then, you open the skill tree, and it grinds to a halt as something snags in
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+your code. Watching the skill tree scroll by like it's a slide show is
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unacceptable. What went wrong? Is it positioning the skill tree elements, the
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UI, or rendering?
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-You could try to optimize everything and running the game again and again, but
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-you can be smarter about this and narrow down the possibilities. Enter Godot's
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-profiler.
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+You could try to optimize everything and run the game repeatedly, but you can be
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+smarter about this and narrow down the possibilities. Enter Godot's profiler.
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An overview of the profiler
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+++++++++++++++++++++++++++
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@@ -21,19 +20,19 @@ An overview of the profiler
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You can open the profiler by opening the **Debugger** panel and clicking on the
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**Profiler** tab.
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-..image:: img/profiler.png
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+.. image:: img/profiler.png
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-Godot's profiler does not run automatically because profiling is
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-performance-intensive. It has to continually measure everything happening in
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-the game and report back to the debugger, so it's off by default.
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+Godot's profiler does not automatically run because profiling is
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+performance-intensive. It has to continually measure everything happening in the
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+game and report back to the debugger, so it's off by default.
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To begin profiling, click on the **Start** button in the top-left. Run your game
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and data will start appearing. You can also start profiling at any time before
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or during gameplay, depending on if you want.
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-You can clear the data by clicking the **Clear** button anytime. Use the **Measure**
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-drop-down menu to change the type of data you measure. The measurements panel
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-and the graph will update accordingly.
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+You can clear the data by clicking the **Clear** button anytime. Use the
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+**Measure** drop-down menu to change the type of data you measure. The
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+measurements panel and the graph will update accordingly.
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The measured data
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+++++++++++++++++
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@@ -46,90 +45,94 @@ The main measurements are frame time, physics time, idle time, and physics time.
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- The **frame time** is the time it takes Godot to execute all the logic for an
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entire image, from physics to rendering.
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- **Physics frame** is the time Godot has allocated between physics updates. In
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- an ideal scenario, the frame time is whatever you chose: 16.66 milliseconds
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- by default, which corresponds to 60FPS. It's a frame of reference you can use
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- for everything else around it.
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-- **Idle time** is the time Godot took to update logic other than physics, such as
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- code that lives in `_process` or timers and cameras set to update on **Idle**.
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+ an ideal scenario, the frame time is whatever you chose: 16.66 milliseconds by
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+ default, which corresponds to 60FPS. It's a frame of reference you can use for
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+ everything else around it.
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+- **Idle time** is the time Godot took to update logic other than physics, such
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+ as code that lives in `_process` or timers and cameras set to update on
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+ **Idle**.
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- **Physics time** is the time Godot took to update physics tasks, like
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`_physics_process` and built-in nodes set to **Physics** update.
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-
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.. note:: In Godot 3, **Frame Time** includes rendering time. Say you find a
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- mysterious spike of lag in your game, but your physics and scripts
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- are all running fast. The delay could be due to the appearance of
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+ mysterious spike of lag in your game, but your physics and scripts are
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+ all running fast. The delay could be due to the appearance of
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particles or visual effects!
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-By default, Godot ticks on Frame Time and Physics Time. This gives you an overview
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-of how long each frame takes relative to the allocated desired physics FPS. You can
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-toggle functions on and off by clicking the checkboxes on the left. Other facilities
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-make appearances as you go down the list, like Physics 2D, Physics, and Audio,
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-before reaching Script functions, where your code appears.
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+By default, Godot ticks on Frame Time and Physics Time. This gives you an
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+overview of how long each frame takes relative to the allocated desired physics
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+FPS. You can toggle functions on and off by clicking the checkboxes on the left.
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+Other facilities make appearances as you go down the list, like Physics 2D,
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+Physics, and Audio, before reaching Script functions, where your code appears.
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-If you click on the graph, you change which frame's information appears on the left.
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-In the top right, there is also a frame counter where you can manually adjust the
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-frame you are looking at more granularly.
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+If you click on the graph, you change which frame's information appears on the
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+left. In the top right, there is also a frame counter where you can manually
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+adjust the frame you are looking at more granularly.
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Scope of measurement and measurement windows
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++++++++++++++++++++++++++++++++++++++++++++
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-You can change what measurement you are looking at using the **Measure** drop-down
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-menu. By default, it starts with Frame Time and lists the time it takes to go through
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-the frame in milliseconds. The average time is the average time any given function
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-took when called more than once. For example, a function that took 0.05 milliseconds
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-to run five times should give you an average of 0.01 milliseconds.
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+You can change what measurement you are looking at using the **Measure**
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+drop-down menu. By default, it starts with Frame Time and lists the time it
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+takes to go through the frame in milliseconds. The average time is the average
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+time any given function took when called more than once. For example, a function
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+that took 0.05 milliseconds to run five times should give you an average of 0.01
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+milliseconds.
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-If accurate milliseconds count are not important, and you want to see proportions of
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-time relative to the rest of the frame, use percentage measurements. Frame % is
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-relative to Frame Time, and Physics % is relative to Physics Time.
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+If accurate milliseconds count is not important, and you want to see proportions
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+of time relative to the rest of the frame, use percentage measurements. Frame %
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+is relative to Frame Time, and Physics % is relative to Physics Time.
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-The last option is the scope of the time. **Inclusive** measures the time a function
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-took **with** any nested function calls. For example:
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+The last option is the scope of the time. **Inclusive** measures the time a
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+function took **with** any nested function calls. For example:
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-..image:: img/split_curve.png
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+.. image:: img/split_curve.png
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-`get_neighbors`, `find_nearest_neighbor` and `move_subject` all took a lot of time.
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-You could be fooled into thinking that this is because all three of them are slow.
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+`get_neighbors`, `find_nearest_neighbor` and `move_subject` all took a lot of
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+time. You could be fooled into thinking that this is because all three of them
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+are slow.
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-But when changed to **Self**, Godot measures the time spent in the function body without
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-considering function calls it made itself.
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+But when changed to **Self**, Godot measures the time spent in the function body
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+without considering function calls it made itself.
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-..image:: img/self_curve.png
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+.. image:: img/self_curve.png
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You can see that `get_neighbors` and `move_subject` have lost a lot of their
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-importance. In effect, that means that `get_neighbors` and `move_subject` have spent
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-more time waiting for some other function call to finish than not, and
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+importance. In effect, that means that `get_neighbors` and `move_subject` have
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+spent more time waiting for some other function call to finish than not, and
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`find_nearest_neighbor` is **actually** slow.
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Debugging slow code with the profiler
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+++++++++++++++++++++++++++++++++++++
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-Finding slow code with the profiler boils down to running your game and watching the
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-performance graph as it draws. When an unacceptable spike occurs in the frame time,
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-you can click on the graph to pause your game and narrow the _Frame #_ to the start
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-of the spike. You may need to jump back and forth between frames and functions to
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-find the root cause.
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+Finding slow code with the profiler boils down to running your game and watching
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+the performance graph as it draws. When an unacceptable spike occurs in the
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+frame time, you can click on the graph to pause your game and narrow the _Frame
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+#_ to the spike's start. You may need to jump back and forth between frames and
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+functions to find the root cause.
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-Under the Script functions, turn on the checkboxes for some functions to find which
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-take time. These are the functions you need to review and optimize.
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+Under the Script functions, turn on the checkboxes for some functions to find
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+which take time. These are the functions you need to review and optimize.
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Measuring manually in microseconds
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++++++++++++++++++++++++++++++++++
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-If your function is complex, it could be challenging to figure out which part needs
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-optimization. Is it your math or the way you access other pieces of data to do the
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-math with? Is it the `for` loop? The `if` statements?
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+If your function is complex, it could be challenging to figure out which part
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+needs optimization. Is it your math or the way you access other pieces of data
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+to do the math with? Is it the `for` loop? The `if` statements?
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-You can narrow down the measurement by manually counting ticks as the code runs with
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-some temporary functions. The two functions are part of the `OS` class object. They
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-are `get_ticks_msec` and `get_ticks_usec`. The first measures in milliseconds (1,000
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-per second) and the second measures in microseconds (1,000,000 per second).
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+You can narrow down the measurement by manually counting ticks as the code runs
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+with some temporary functions. The two functions are part of the `OS` class
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+object. They are `get_ticks_msec` and `get_ticks_usec`. The first measures in
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+milliseconds (1,000 per second), and the second measures in microseconds
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+(1,000,000 per second).
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-Either one returns the amount of time since the game started in their respective time
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-frame. This comes directly from the operating system rather than Godot.
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+Either one returns the amount of time since the game started in their respective
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+time frame. This comes directly from the operating system rather than Godot.
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-If you wrap a piece of code with a start and end count of microseconds, the difference
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-between the two is the amount of time it took to run that piece of code.
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+If you wrap a piece of code with a start and end count of microseconds, the
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+difference between the two is the amount of time it took to run that piece of
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+code.
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.. tabs::
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.. code-tab:: gdscript GDScript
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@@ -149,9 +152,10 @@ between the two is the amount of time it took to run that piece of code.
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print("Worker time: %s\nLoop time: %s" % [worker_time, loop_time])
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-As you become a more experienced programmer, this technique becomes less necessary.You
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-begin to learn what parts of a running program are slow. Knowing that loops and branches
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-can be slow comes from experience, and you gain experience by measuring and doing research.
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+As you become a more experienced programmer, this technique becomes less
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+necessary. You begin to learn what parts of a running program are slow. Knowing
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+that loops and branches can be slow comes from experience, and you gain
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+experience by measuring and doing research.
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-But between the profiler and the ticks functions, you should have enough to get started
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-finding which parts of your code need optimization.
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+But between the profiler and the ticks functions, you should have enough to get
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+started finding which parts of your code need optimization.
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