Set Up Profiling

With Profiling, Sentry allows you to collect and analyze performance profiles from real users in production to give you a complete picture of how your application performs in a variety of environments.

Under the hood, we're using Wikipedia's sampling profiler Excimer. The Excimer PHP extension supports PHP 7.2 and up.

Installation

Here's how to install Excimer with a Linux package manager, PECL, or build from a source.

Linux Package Manager

apt-get install php-excimer

See https://www.mediawiki.org/wiki/Excimer for additional distributions.

PECL

pecl install excimer

See https://pecl.php.net/package/excimer for more information.

Build From Source

git clone https://github.com/wikimedia/mediawiki-php-excimer.git

cd excimer/
phpize && ./configure && make && sudo make install

Depending on your environment, you may need to enable the Excimer extension afterwards.

phpenmod -s fpm excimer
# or
phpenmod -s apache2 excimer

Enable Tracing

Sentry's tracing product has to be enabled in order for Profiling to work. Check out the performance setup documentation for more detailed information.

sentry:
  options:
    traces_sample_rate: 1.0

Enable Profiling

sentry:
  options:
    traces_sample_rate: 1.0
    # Set a sampling rate for profiling - this is relative to traces_sample_rate
    profiles_sample_rate: 1.0

Improve Response Time

Response time is somewhat impacted when you use the performance capabilities in your Symfony application, (depending on the traces_sample_rate you've configured). If your web server is using FastCGI, our SDK utilizes the kernel.terminate event, which means that the response is sent to the user before the profiling data is sent to Sentry.

If your web server isn't using FastCGI, you can run Relay locally on the same machine or a local network that can act as a proxy/agent. Doing this will make the PHP process send requests to your local Relay, which will then forward them to Sentry, instead of sending requests to Sentry directly.

To begin using Relay, check out our docs for getting started. We recommend using Relay in managed mode (which is the default).

Follow the instructions in the Relay docs to send a test event through Relay to Sentry. Don't forget to update your DSN to point to your running Relay instance. After you've set up Relay, you should see a dramatic improvement in how much your server is impacted.

Troubleshooting

If you don't see any profiling data in sentry.io, you can try the following:

• Ensure that Tracing is enabled.
• Ensure that the automatic instrumentation is sending performance data to Sentry by going to the Performance page in sentry.io.
• If the automatic instrumentation is not sending performance data, try using custom instrumentation.