15.1.18. The code profiler¶

Window → Show Code Profiler opens a function-level profiler for the firmware running on the connected camera: which C functions ran, how often, and where the microseconds went, streamed live while a script executes. It answers the question the FPS counter raises – why is this pipeline slow – at the level of the camera’s own code.

Profiling support is compiled into the firmware, not always present: the camera must be running a firmware built with PROFILE_ENABLE=1, and the menu entry stays disabled otherwise. Building such a firmware is part of the custom-build workflow covered in Building the firmware.

Screenshot needed

figures/profiler.png – the Code Profiler window connected to a profiling firmware build while a script runs: the function table populated with names, calls, and timing columns, the Flat/Tree and Inclusive/Exclusive controls visible, and the totals line at the bottom. Capture the whole window.

The window is a sortable table of functions with their call counts, minimum, maximum, total, and average microseconds, average cycles, and percentage of total time, with a totals line underneath and a filter box for finding functions by name. Function names come from the firmware’s ELF file – point the window’s firmware path field at the .elf produced by the build, and addresses resolve to names.

Two view controls organize the data. Flat ranks every function independently – the view for “what is the single most expensive function.” Tree nests callees under callers, showing how time decomposes down the call chain. Independently, Inclusive charges a function for the time spent in everything it called, while Exclusive counts only the function’s own body – inclusive finds the expensive subsystem, exclusive finds the expensive loop. Reset zeroes the counters, which is how one stage of a pipeline gets measured in isolation: reset, let it run, read.

The profiler can also display hardware event counters – cache misses, branch mispredictions, and the other events the processor can count – alongside the timing columns, selected from the same window on firmware built with the support.