setf the caar of
profiler-report-memory-line-format to a larger width (default 50 and 55).
Update 2021-03-10: As of this commit on 2020-12-22 the profiler layout has been changed for Emacs 28, putting function names at the rightmost column, preventing them from being truncated. So this article only applies to Emacs up to 27.
Emacs's profiler reports have a fixed width, which makes debugging deeply nested function calls difficult.
Ideally the columns would be resized along with the window, or perhaps profiler.el should define its formatting variables with
defcustom. Either way, it is still relatively easy to change the format.
The formatting is stored in two variables,
profiler-report-memory-line-format. They're not explicitly documented, but turns out their
caar fields specify their widths.
In profiler.el (comments added):
To change the width of lines in the profiler report, simply set these to what you want.
And here is a minor mode to do it:
This is a solution to this StackExchange question. Specifically, a comment there pointed out that
profiler-report mentions "width", which led me to find the relevant variables.