Resource usage meter

Adds to HTTP headers of a response the performance data of the request not only
as the actual execution time in seconds (rtime), but also the utime and
stime:

• rtime represents the total duration of the response generation process.

• utime represents the actual CPU time, exclusively spent on processing only
  the PHP code of the current request, excluding other background processes.

• stime represents the CPU time spent on kernel processes like disk read/writes
  and other IO operations.

More information: https://www.baeldung.com/linux/total-process-cpu-usage#2-the-cpu-usage

Additionally, it shows the memory usage and the disk read (inblock) and write (oublock) operations.

An example of the HTTP headers output of a response:

x-rusage-rtime: 3.482499
x-rusage-stime: 0.101052
x-rusage-utime: 2.792771
x-rusage-memory: 91076728
x-rusage-memory-peak: 144699680
x-rusage-inblock: 16216
x-rusage-oublock: 192

An example chart for 10 concurrent requests to the homepage:

The data is collected by the PHP functions getrusage(), microtime(),
memory_get_usage(), memory_get_peak_usage().

Features

The benefit of this approach is to see not only the actual time during which the response is generated but how much resources the server actually spent to generate this response.

This should show more stable time numbers for concurrent requests with less dependency on the background processes load.

Usually, the rtime shows fewer numbers than the request time, but sometimes the utime can show more time than the total request time if the process uses multi-threading.

More documentation can be found here:
https://www.php.net/manual/en/function.getrusage.php

Post-Installation

The module works out of the box without any configuration, and is controlled by the environment variables:

• RUSAGE_METER_INJECT_ALWAYS=1 - enables injecting headers always.
• RUSAGE_METER_INJECT_KEY=put-an-unique-key-here - enables injecting headers only for requests with the GET query parameter rusage-meter-key or the HTTP header x-rusage-meter-key equals to the configured string.

By default, it counts the resource usage of the span from the request processing start event (KernelEvents::REQUEST) time to the response created event (KernelEvents::RESPONSE).

If you want to include also the Kernel initialization flow, you should manually extend your index.php file like this:

  use Symfony\Component\HttpFoundation\Request;

+ // Sets the initial resource usage data for the `rusage_meter` module.
+ require 'modules/contrib/rusage_meter/rusage_meter_initial.inc.php';
+
  $autoloader = require_once 'autoload.php';

Also, you can push initial and final data in your own places of the code, to measure the exact part of your business logic, by using the service:

\Drupal::service('rusage_meter')->setInitialData(array $data = NULL, bool $override = TRUE);
// Do some stuff.
\Drupal::service('rusage_meter')->setFinalData(array $data = NULL, bool $override = TRUE);

If the $data array is null, it will get the current values, if not null - put
your custom values.

And if you want to optimize some specific part of your code before the Drupal kernel is initialized, for example, the autoloader, you can wrap it by requiring the initial and final data, like this:

+ require 'modules/contrib/rusage_meter/rusage_meter_initial.inc.php';
  $autoloader = require_once 'autoload.php';
+ require 'modules/contrib/rusage_meter/rusage_meter_final.inc.php';

Additional Requirements

No additional requirements or dependencies.

Recommended modules/libraries

If you're interested in monitoring and optimizing the performance of your website, please try also my other module OpenTelemetry.

Similar projects

I haven't found any similar module, if you know one - please tell me!

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