flamegraph.pl

#!/usr/bin/perl -w
#
# flamegraph.pl		flame stack grapher.
#
# This takes stack samples and renders a call graph, allowing hot functions
# and codepaths to be quickly identified.  Stack samples can be generated using
# tools such as DTrace, perf, SystemTap, and Instruments.
#
# USAGE: ./flamegraph.pl [options] input.txt > graph.svg
#
#        grep funcA input.txt | ./flamegraph.pl [options] > graph.svg
#
# Then open the resulting .svg in a web browser, for interactivity: mouse-over
# frames for info, click to zoom, and ctrl-F to search.
#
# Options are listed in the usage message (--help).
#
# The input is stack frames and sample counts formatted as single lines.  Each
# frame in the stack is semicolon separated, with a space and count at the end
# of the line.  These can be generated for Linux perf script output using
# stackcollapse-perf.pl, for DTrace using stackcollapse.pl, and for other tools
# using the other stackcollapse programs.  Example input:
#
#  swapper;start_kernel;rest_init;cpu_idle;default_idle;native_safe_halt 1
#
# An optional extra column of counts can be provided to generate a differential
# flame graph of the counts, colored red for more, and blue for less.  This
# can be useful when using flame graphs for non-regression testing.
# See the header comment in the difffolded.pl program for instructions.
#
# The input functions can optionally have annotations at the end of each
# function name, following a precedent by some tools (Linux perf's _[k]):
# 	_[k] for kernel
#	_[i] for inlined
#	_[j] for jit
#	_[w] for waker
# Some of the stackcollapse programs support adding these annotations, eg,
# stackcollapse-perf.pl --kernel --jit. They are used merely for colors by
# some palettes, eg, flamegraph.pl --color=java.
#
# The output flame graph shows relative presence of functions in stack samples.
# The ordering on the x-axis has no meaning; since the data is samples, time
# order of events is not known.  The order used sorts function names
# alphabetically.
#
# While intended to process stack samples, this can also process stack traces.
# For example, tracing stacks for memory allocation, or resource usage.  You
# can use --title to set the title to reflect the content, and --countname
# to change "samples" to "bytes" etc.
#
# There are a few different palettes, selectable using --color.  By default,
# the colors are selected at random (except for differentials).  Functions
# called "-" will be printed gray, which can be used for stack separators (eg,
# between user and kernel stacks).
#
# HISTORY
#
# This was inspired by Neelakanth Nadgir's excellent function_call_graph.rb
# program, which visualized function entry and return trace events.  As Neel
# wrote: "The output displayed is inspired by Roch's CallStackAnalyzer which
# was in turn inspired by the work on vftrace by Jan Boerhout".  See:
# https://blogs.oracle.com/realneel/entry/visualizing_callstacks_via_dtrace_and
#
# Copyright 2016 Netflix, Inc.
# Copyright 2011 Joyent, Inc.  All rights reserved.
# Copyright 2011 Brendan Gregg.  All rights reserved.
#
# CDDL HEADER START
#
# The contents of this file are subject to the terms of the