This section describes how to read the timeline of a profile. You can also
visualize a profile as a
The timeline representation of a profile is a great way to analyze the
wall-clock time of the most important function calls, which are represented as
Like for the call-graph, Blackfire filters unimportant calls to only display
the most significant ones. Blackfire also automatically understands which
libraries you are using and groups similar calls as metrics that show up in
the left pane.
The global memory usage is displayed in the navigation panel as a light blue
graph. It represents the growing peak memory enveloppe. A sudden increase can
give you a hint on which function calls consume more memory.
On PHP profiles, the memory graph is an always-growing-graph. As it
represents the peak memory, you can never see it decreasing, even if you
manually clear your application memory.
The threshold timeline metric highlights one or several event blocks in
the Timeline view. It is designed to draw your attention on something that
Blackfire considers significant.
The timeline threshold is a value computed when a profile is triggered.
When you ask for a profile with a Blackfire client, e.g. with Blackfire
browser extension, it first fires a pre-flight
request that will not be profiled. The duration of this request is taken as a
reference in order to calculate the threshold value.
The threshold value is calculated as 1% of the duration of the pre-flight
This value is displayed in the metadata panel of your profile that you can
view by hovering on your profile name.
This value is a reference for Blackfire in order to detect significant
events for you.
Considering the threshold value, significant events are function calls that
are worth paying attention to, an event being usually considered significant
when its exclusive wall-time exceeds the threshold value.
The timeline only displays relevant metrics that are configured and curated by
the Blackfire team.
But you can also add more information by creating your own custom
metrics ready for the timeline.
Markers allow you to visualize cue-points you explicitly define in your code.
Call \BlackfireProbe::addMarker($markerName) to define a marker:
\BlackfireProbe::addMarker() is production safe. When no profile
is requested, this function call operates as a no-op instruction.