path: root/tools/perf/Documentation/perf-config.txt

perf-config(1)
==============

NAME
----
perf-config - Get and set variables in a configuration file.

SYNOPSIS
--------
[verse]
'perf config' [<file-option>] [section.name ...]
or
'perf config' [<file-option>] -l | --list

DESCRIPTION
-----------
You can manage variables in a configuration file with this command.

OPTIONS
-------

-l::
--list::
	Show current config variables, name and value, for all sections.

--user::
	For writing and reading options: write to user
	'$HOME/.perfconfig' file or read it.

--system::
	For writing and reading options: write to system-wide
	'$(sysconfdir)/perfconfig' or read it.

CONFIGURATION FILE
------------------

The perf configuration file contains many variables to change various
aspects of each of its tools, including output, disk usage, etc.
The '$HOME/.perfconfig' file is used to store a per-user configuration.
The file '$(sysconfdir)/perfconfig' can be used to
store a system-wide default configuration.

When reading or writing, the values are read from the system and user
configuration files by default, and options '--system' and '--user'
can be used to tell the command to read from or write to only that location.

Syntax
~~~~~~

The file consist of sections. A section starts with its name
surrounded by square brackets and continues till the next section
begins. Each variable must be in a section, and have the form
'name = value', for example:

	[section]
		name1 = value1
		name2 = value2

Section names are case sensitive and can contain any characters except
newline (double quote `"` and backslash have to be escaped as `\"` and `\\`,
respectively). Section headers can't span multiple lines.

Example
~~~~~~~

Given a $HOME/.perfconfig like this:

#
# This is the config file, and
# a '#' and ';' character indicates a comment
#

	[colors]
		# Color variables
		top = red, default
		medium = green, default
		normal = lightgray, default
		selected = white, lightgray
		jump_arrows = blue, default
		addr = magenta, default
		root = white, blue

	[tui]
		# Defaults if linked with libslang
		report = on
		annotate = on
		top = on

	[buildid]
		# Default, disable using /dev/null
		dir = ~/.debug

	[annotate]
		# Defaults
		hide_src_code = false
		use_offset = true
		jump_arrows = true
		show_nr_jumps = false

	[help]
		# Format can be man, info, web or html
		format = man
		autocorrect = 0

	[ui]
		show-headers = true

	[call-graph]
		# fp (framepointer), dwarf
		record-mode = fp
		print-type = graph
		order = caller
		sort-key = function

	[report]
		# Defaults
		sort-order = comm,dso,symbol
		percent-limit = 0
		queue-size = 0
		children = true
		group = true

To query the record mode of call graph, do

	% perf config call-graph.record-mode

If you want to know multiple config key/value pairs, you can do like

	% perf config report.queue-size call-graph.order report.children

To query the config value of sort order of call graph in user config file (i.e. `~/.perfconfig`), do

	% perf config --user call-graph.sort-order

To query the config value of buildid directory in system config file (i.e. `$(sysconf)/perfconfig`), do

	% perf config --system buildid.dir

Variables
~~~~~~~~~

colors.*::
	The variables for customizing the colors used in the output for the
	'report', 'top' and 'annotate' in the TUI. They should specify the
	foreground and background colors, separated by a comma, for example:

		medium = green, lightgray

	If you want to use the color configured for you terminal, just leave it
	as 'default', for example:

		medium = default, lightgray

	Available colors:
	red, yellow, green, cyan, gray, black, blue,
	white, default, magenta, lightgray

	colors.top::
		'top' means a overhead percentage which is more than 5%.
		And values of this variable specify percentage colors.
		Basic key values are foreground-color 'red' and
		background-color 'default'.
	colors.medium::
		'medium' means a overhead percentage which has more than 0.5%.
		Default values are 'green' and 'default'.
	colors.normal::
		'normal' means the rest of overhead percentages
		except 'top', 'medium', 'selected'.
		Default values are 'lightgray' and 'default'.
	colors.selected::
		This selects the colors for the current entry in a list of entries
		from sub-commands (top, report, annotate).
		Default values are 'black' and 'lightgray'.
	colors.jump_arrows::
		Colors for jump arrows on assembly code listings
		such as 'jns', 'jmp', 'jane', etc.
		Default values are 'blue', 'default'.
	colors.addr::
		This selects colors for addresses from 'annotate'.
		Default values are 'magenta', 'default'.
	colors.root::
		Colors for headers in the output of a sub-commands (top, report).
		Default values are 'white', 'blue'.

tui.*, gtk.*::
	Subcommands that can be configured here are 'top', 'report' and 'annotate'.
	These values are booleans, for example:

	[tui]
		top = true

	will make the TUI be the default for the 'top' subcommand. Those will be
	available if the required libs were detected at tool build time.

buildid.*::
	buildid.dir::
		Each executable and shared library in modern distributions comes with a
		content based identifier that, if available, will be inserted in a
		'perf.data' file header to, at analysis time find what is needed to do
		symbol resolution, code annotation, etc.

		The recording tools also stores a hard link or copy in a per-user
		directory, $HOME/.debug/, of binaries, shared libraries, /proc/kallsyms
		and /proc/kcore files to be used at analysis time.

		The buildid.dir variable can be used to either change this directory
		cache location, or to disable it altogether. If you want to disable it,
		set buildid.dir to /dev/null. The default is $HOME/.debug

annotate.*::
	These options work only for TUI.
	These are in control of addresses, jump function, source code
	in lines of assembly code from a specific program.

	annotate.hide_src_code::
		If a program which is analyzed has source code,
		this option lets 'annotate' print a list of assembly code with the source code.
		For example, let's see a part of a program. There're four lines.
		If this option is 'true', they can be printed
		without source code from a program as below.

		│        push   %rbp
		│        mov    %rsp,%rbp
		│        sub    $0x10,%rsp
		│        mov    (%rdi),%rdx

		But if this option is 'false', source code of the part
		can be also printed as below. Default is 'false'.

		│      struct rb_node *rb_next(const struct rb_node *node)
		│      {
		│        push   %rbp
		│        mov    %rsp,%rbp
		│        sub    $0x10,%rsp
		│              struct rb_node *parent;
		│
		│              if (RB_EMPTY_NODE(node))
		│        mov    (%rdi),%rdx
		│              return n;

        annotate.use_offset::
		Basing on a first address of a loaded function, offset can be used.
		Instead of using original addresses of assembly code,
		addresses subtracted from a base address can be printed.
		Let's illustrate an example.
		If a base address is 0XFFFFFFFF81624d50 as below,

		ffffffff81624d50 <load0>

		an address on assembly code has a specific absolute address as below

		ffffffff816250b8:│  mov    0x8(%r14),%rdi

		but if use_offset is 'true', an address subtracted from a base address is printed.
		Default is true. This option is only applied to TUI.

		             368:│  mov    0x8(%r14),%rdi

	annotate.jump_arrows::
		There can be jump instruction among assembly code.
		Depending on a boolean value of jump_arrows,
		arrows can be printed or not which represent
		where do the instruction jump into as below.

		│     ┌──jmp    1333
		│     │  xchg   %ax,%ax
		│1330:│  mov    %r15,%r10
		│1333:└─→cmp    %r15,%r14

		If jump_arrow is 'false', the arrows isn't printed as below.
		Default is 'false'.

		│      ↓ jmp    1333
		│        xchg   %ax,%ax
		│1330:   mov    %r15,%r10
		│1333:   cmp    %r15,%r14

        annotate.show_linenr::
		When showing source code if this option is 'true',
		line numbers are printed as below.

		│1628         if (type & PERF_SAMPLE_IDENTIFIER) {
		│     ↓ jne    508
		│1628                 data->id = *array;
		│1629                 array++;
		│1630         }

		However if this option is 'false', they aren't printed as below.
		Default is 'false'.

		│             if (type & PERF_SAMPLE_IDENTIFIER) {
		│     ↓ jne    508
		│                     data->id = *array;
		│                     array++;
		│             }

        annotate.show_nr_jumps::
		Let's see a part of assembly code.

		│1382:   movb   $0x1,-0x270(%rbp)

		If use this, the number of branches jumping to that address can be printed as below.
		Default is 'false'.

		│1 1382:   movb   $0x1,-0x270(%rbp)

        annotate.show_total_period::
		To compare two records on an instruction base, with this option
		provided, display total number of samples that belong to a line
		in assembly code. If this option is 'true', total periods are printed
		instead of percent values as below.

		  302 │      mov    %eax,%eax

		But if this option is 'false', percent values for overhead are printed i.e.
		Default is 'false'.

		99.93 │      mov    %eax,%eax

hist.*::
	hist.percentage::
		This option control the way to calculate overhead of filtered entries -
		that means the value of this option is effective only if there's a
		filter (by comm, dso or symbol name). Suppose a following example:

		       Overhead  Symbols
		       ........  .......
		        33.33%     foo
		        33.33%     bar
		        33.33%     baz

	       This is an original overhead and we'll filter out the first 'foo'
	       entry. The value of 'relative' would increase the overhead of 'bar'
	       and 'baz' to 50.00% for each, while 'absolute' would show their
	       current overhead (33.33%).

ui.*::
	ui.show-headers::
		This option controls display of column headers (like 'Overhead' and 'Symbol')
		in 'report' and 'top'. If this option is false, they are hidden.
		This option is only applied to TUI.

call-graph.*::
	When sub-commands 'top' and 'report' work with -g/—-children
	there're options in control of call-graph.

	call-graph.record-mode::
		The record-mode can be 'fp' (frame pointer), 'dwarf' and 'lbr'.
		The value of 'dwarf' is effective only if perf detect needed library
		(libunwind or a recent version of libdw).
		'lbr' only work for cpus that support it.

	call-graph.dump-size::
		The size of stack to dump in order to do post-unwinding. Default is 8192 (byte).
		When using dwarf into record-mode, the default size will be used if omitted.

	call-graph.print-type::
		The print-types can be graph (graph absolute), fractal (graph relative),
		flat and folded. This option controls a way to show overhead for each callchain
		entry. Suppose a following example.

                Overhead  Symbols
                ........  .......
                  40.00%  foo
                          |
                          ---foo
                             |
                             |--50.00%--bar
                             |          main
                             |
                              --50.00%--baz
                                        main

		This output is a 'fractal' format. The 'foo' came from 'bar' and 'baz' exactly
		half and half so 'fractal' shows 50.00% for each
		(meaning that it assumes 100% total overhead of 'foo').

		The 'graph' uses absolute overhead value of 'foo' as total so each of
		'bar' and 'baz' callchain will have 20.00% of overhead.
		If 'flat' is used, single column and linear exposure of call chains.
		'folded' mean call chains are displayed in a line, separated by semicolons.

	call-graph.order::
		This option controls print order of callchains. The default is
		'callee' which means callee is printed at top and then followed by its
		caller and so on. The 'caller' prints it in reverse order.

		If this option is not set and report.children or top.children is
		set to true (or the equivalent command line option is given),
		the default value of this option is changed to 'caller' for the
		execution of 'perf report' or 'perf top'. Other commands will
		still default to 'callee'.

	call-graph.sort-key::
		The callchains are merged if they contain same information.
		The sort-key option determines a way to compare the callchains.
		A value of 'sort-key' can be 'function' or 'address'.
		The default is 'function'.

	call-graph.threshold::
		When there're many callchains it'd print tons of lines. So perf omits
		small callchains under a certain overhead (threshold) and this option
		control the threshold. Default is 0.5 (%). The overhead is calculated
		by value depends on call-graph.print-type.

	call-graph.print-limit::
		This is a maximum number of lines of callchain printed for a single
		histogram entry. Default is 0 which means no limitation.

report.*::
	report.sort_order::
		Allows changing the default sort order from "comm,dso,symbol" to
		some other default, for instance "sym,dso" may be more fitting for
		kernel developers.
	report.percent-limit::
		This one is mostly the same as call-graph.threshold but works for
		histogram entries. Entries having an overhead lower than this
		percentage will not be printed. Default is '0'. If percent-limit
		is '10', only entries which have more than 10% of overhead will be
		printed.

	report.queue-size::
		This option sets up the maximum allocation size of the internal
		event queue for ordering events. Default is 0, meaning no limit.

	report.children::
		'Children' means functions called from another function.
		If this option is true, 'perf report' cumulates callchains of children
		and show (accumulated) total overhead as well as 'Self' overhead.
		Please refer to the 'perf report' manual. The default is 'true'.

	report.group::
		This option is to show event group information together.
		Example output with this turned on, notice that there is one column
		per event in the group, ref-cycles and cycles:

		# group: {ref-cycles,cycles}
		# ========
		#
		# Samples: 7K of event 'anon group { ref-cycles, cycles }'
		# Event count (approx.): 6876107743
		#
		#         Overhead  Command      Shared Object               Symbol
		# ................  .......  .................  ...................
		#
		    99.84%  99.76%  noploop  noploop            [.] main
		     0.07%   0.00%  noploop  ld-2.15.so         [.] strcmp
		     0.03%   0.00%  noploop  [kernel.kallsyms]  [k] timerqueue_del

top.*::
	top.children::
		Same as 'report.children'. So if it is enabled, the output of 'top'
		command will have 'Children' overhead column as well as 'Self' overhead
		column by default.
		The default is 'true'.

man.*::
	man.viewer::
		This option can assign a tool to view manual pages when 'help'
		subcommand was invoked. Supported tools are 'man', 'woman'
		(with emacs client) and 'konqueror'. Default is 'man'.

		New man viewer tool can be also added using 'man.<tool>.cmd'
		or use different path using 'man.<tool>.path' config option.

pager.*::
	pager.<subcommand>::
		When the subcommand is run on stdio, determine whether it uses
		pager or not based on this value. Default is 'unspecified'.

kmem.*::
	kmem.default::
		This option decides which allocator is to be analyzed if neither
		'--slab' nor '--page' option is used. Default is 'slab'.

record.*::
	record.build-id::
		This option can be 'cache', 'no-cache' or 'skip'.
		'cache' is to post-process data and save/update the binaries into
		the build-id cache (in ~/.debug). This is the default.
		But if this option is 'no-cache', it will not update the build-id cache.
		'skip' skips post-processing and does not update the cache.

SEE ALSO
--------
linkperf:perf[1]