What does it do?
Blackfire enables you to gather information on how your back-end code is consuming resources.
That is achieved with two measurement techniques: profiling and monitoring.
How Does Monitoring Work?
Blackfire automatically generates "traces" based on your real-end-user traffic. Once Blackfire is installed on your servers, and that you completed the configuration procedure, data will automatically start flowing in, with no further interaction from you.
If you have completed the configuration, have an active Blackfire Monitoring subscription but do no see any data coming in, please contact our support team.
How Does Profiling Work?
Blackfire "profiles" are generated only for requests triggered by a Blackfire user (through our browser extension, SDK or CLI), or by Blackfire when profiling is automated (Blackfire Builds).
That is made possible thanks to our runtime instrumentation. As no other requests will be instrumented, Blackfire will add no overhead for your end users, which makes it safe to use in production. Another benefit of the on-the-fly runtime instrumentation is that you do not need to modify your code to get profiling data. Which makes it much more scalable when releasing to production.
To better understand how Blackfire works, check our doc on the Blackfire stack.