gprof

TLDR

Generate profile report

$ gprof [program] [gmon.out]

Flat profile only

$ gprof -p [program]

Call graph only

$ gprof -q [program]

Suppress static functions

$ gprof -a [program]

Output to file

$ gprof [program] > [profile.txt]

SYNOPSIS

gprof [options] [executable] [profile-data]

gprof analyzes program execution profiles to identify performance bottlenecks. It requires programs compiled with -pg flag and produces reports showing time spent in each function and call relationships.
The tool generates two main reports: a flat profile showing time per function, and a call graph showing function relationships and cumulative times.

PARAMETERS

-p, --flat-profile

Print flat profile only.

-q, --graph

Print call graph only.

-b, --brief

Suppress explanatory text.

-a, --no-static

Suppress static functions.

-z, --display-unused-functions

Show functions never called.

-c, --static-call-graph

Include static call graph.

-A, --annotated-source

Print annotated source.

-l, --line

Line-by-line profiling.

WORKFLOW

$ # 1. Compile with profiling
gcc -pg -o program program.c

# 2. Run program (generates gmon.out)
./program

# 3. Analyze profile
gprof program gmon.out > analysis.txt

CAVEATS

Requires recompilation with -pg. Adds overhead to execution. Sampling-based; short-running functions may be underrepresented. Modern alternatives include perf and valgrind.

HISTORY

gprof was developed at UC Berkeley in the early 1980s by Susan Graham, Peter Kessler, and Marshall McKusick. It became the standard Unix profiler and remains part of GNU binutils.