Incompatibilities with Unix gprof

GNU gprof and Berkeley Unix gprof use the same data file gmon.out, and provide essentially the same information. But there are a few differences.

• GNU gprof uses a new, generalized file format with support for basic-block execution counts and non-realtime histograms. A magic cookie and version number allows gprof to easily identify new style files. Old BSD-style files can still be read. See File Format.
• For a recursive function, Unix gprof lists the function as a parent and as a child, with a calls field that lists the number of recursive calls. GNU gprof omits these lines and puts the number of recursive calls in the primary line.
• When a function is suppressed from the call graph with -e, GNU gprof still lists it as a subroutine of functions that call it.
• GNU gprof accepts the -k with its argument in the form from/to, instead of from to.
• In the annotated source listing, if there are multiple basic blocks on the same line, GNU gprof prints all of their counts, separated by commas.
• The blurbs, field widths, and output formats are different. GNU gprof prints blurbs after the tables, so that you can see the tables without skipping the blurbs.