Merged with develop and updated to new changelog.

1 files changed, 122 insertions, 0 deletions

diff --git a/user_guide_src/source/libraries/benchmark.rst b/user_guide_src/source/libraries/benchmark.rst
new file mode 100644
index 000000000..5b86142dd
--- /dev/null
+++ b/user_guide_src/source/libraries/benchmark.rst
@@ -0,0 +1,122 @@
+##################
+Benchmarking Class
+##################
+
+CodeIgniter has a Benchmarking class that is always active, enabling the
+time difference between any two marked points to be calculated.
+
+.. note:: This class is initialized automatically by the system so there
+	is no need to do it manually.
+
+In addition, the benchmark is always started the moment the framework is
+invoked, and ended by the output class right before sending the final
+view to the browser, enabling a very accurate timing of the entire
+system execution to be shown.
+
+.. contents:: Table of Contents
+
+Using the Benchmark Class
+=========================
+
+The Benchmark class can be used within your
+:doc:`controllers </general/controllers>`,
+:doc:`views </general/views>`, or your :doc:`models </general/models>`.
+The process for usage is this:
+
+#. Mark a start point
+#. Mark an end point
+#. Run the "elapsed time" function to view the results
+
+Here's an example using real code::
+
+	$this->benchmark->mark('code_start');
+
+	// Some code happens here
+
+	$this->benchmark->mark('code_end');
+
+	echo $this->benchmark->elapsed_time('code_start', 'code_end');
+
+.. note:: The words "code_start" and "code_end" are arbitrary. They
+	are simply words used to set two markers. You can use any words you
+	want, and you can set multiple sets of markers. Consider this example::
+
+		$this->benchmark->mark('dog');
+
+		// Some code happens here
+
+		$this->benchmark->mark('cat');
+
+		// More code happens here
+
+		$this->benchmark->mark('bird');
+
+		echo $this->benchmark->elapsed_time('dog', 'cat');
+		echo $this->benchmark->elapsed_time('cat', 'bird');
+		echo $this->benchmark->elapsed_time('dog', 'bird');
+
+
+Profiling Your Benchmark Points
+===============================
+
+If you want your benchmark data to be available to the
+:doc:`Profiler </general/profiling>` all of your marked points must
+be set up in pairs, and each mark point name must end with _start and
+_end. Each pair of points must otherwise be named identically. Example::
+
+	$this->benchmark->mark('my_mark_start');
+
+	// Some code happens here...
+
+	$this->benchmark->mark('my_mark_end'); 
+
+	$this->benchmark->mark('another_mark_start');
+
+	// Some more code happens here...
+
+	$this->benchmark->mark('another_mark_end');
+
+Please read the :doc:`Profiler page </general/profiling>` for more
+information.
+
+Displaying Total Execution Time
+===============================
+
+If you would like to display the total elapsed time from the moment
+CodeIgniter starts to the moment the final output is sent to the
+browser, simply place this in one of your view templates::
+
+	<?php echo $this->benchmark->elapsed_time();?>
+
+You'll notice that it's the same function used in the examples above to
+calculate the time between two point, except you are **not** using any
+parameters. When the parameters are absent, CodeIgniter does not stop
+the benchmark until right before the final output is sent to the
+browser. It doesn't matter where you use the function call, the timer
+will continue to run until the very end.
+
+An alternate way to show your elapsed time in your view files is to use
+this pseudo-variable, if you prefer not to use the pure PHP::
+
+	{elapsed_time}
+
+.. note:: If you want to benchmark anything within your controller
+	functions you must set your own start/end points.
+
+Displaying Memory Consumption
+=============================
+
+If your PHP installation is configured with --enable-memory-limit, you
+can display the amount of memory consumed by the entire system using the
+following code in one of your view file::
+
+	<?php echo $this->benchmark->memory_usage();?>
+
+.. note:: This function can only be used in your view files. The consumption
+	will reflect the total memory used by the entire app.
+
+An alternate way to show your memory usage in your view files is to use
+this pseudo-variable, if you prefer not to use the pure PHP::
+
+	{memory_usage}
+