perf-config(1) - Man pages

PERF-CONFIG(1) perf Manual PERF-CONFIG(1)

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

SYNOPSIS
perf config [<file-option>] [section.name[=value] ...]
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.

One an disable reading config files by setting the PERF_CONFIG
environment variable to /dev/null, or provide an alternate config file
by setting that variable.

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
skip-empty = true

You can hide source code of annotate feature setting the config to
false with

% perf config annotate.hide_src_code=true

If you want to add or modify several config items, you can do like

% perf config ui.show-headers=false kmem.default=slab

To modify the sort order of report functionality in user config
file(i.e. ~/.perfconfig), do

% perf config --user report.sort-order=srcline

To change colors of selected line to other foreground and background
colors in system config file (i.e. $(sysconf)/perfconfig), do

% perf config --system colors.selected=yellow,green

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.

core.*, core.proc-map-timeout
Sets a timeout (in milliseconds) for parsing /proc/<pid>/maps
files. Can be overridden by the --proc-map-timeout option on
supported subcommands. The default timeout is 500ms.

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

buildid-cache.*
buildid-cache.debuginfod=URLs Specify debuginfod URLs to be used
when retrieving perf.data binaries, it follows the same syntax as
the DEBUGINFOD_URLS variable, like:

buildid-cache.debuginfod=http://192.168.122.174:8002

annotate.*
These are in control of addresses, jump function, source code in
lines of assembly code from a specific program.

annotate.addr2line
addr2line binary to use for file names and line numbers.

annotate.objdump
objdump binary to use for disassembly and annotations, including in
the perf test command.

annotate.disassembler_style
Use this to change the default disassembler style to some other
value supported by binutils, such as "intel", see the -M option
help in the objdump man page.

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;

This option works with tui, stdio2 browsers.

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

This option works with tui, stdio2 browsers.

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

This option works with tui browser.

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++;
│ }

This option works with tui, stdio2 browsers.

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)

This option works with tui, stdio2 browsers.

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

This option works with tui, stdio2, stdio browsers.

annotate.show_nr_samples
By default perf annotate shows percentage of samples. This option
can be used to print absolute number of samples. Ex, when set as
false:

Percent│
74.03 │ mov %fs:0x28,%rax

When set as true:

Samples│
6 │ mov %fs:0x28,%rax

This option works with tui, stdio2, stdio browsers.

annotate.offset_level
Default is 1, meaning just jump targets will have offsets show
right beside the instruction. When set to 2 call instructions will
also have its offsets shown, 3 or higher will show offsets for all
instructions.

This option works with tui, stdio2 browsers.

annotate.demangle
Demangle symbol names to human readable form. Default is true.

annotate.demangle_kernel
Demangle kernel symbol names to human readable form. Default is
true.

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.*
The following controls the handling of call-graphs (obtained via
the -g/--call-graph options).

call-graph.record-mode
The mode for user space can be fp (frame pointer), dwarf and lbr.
The value dwarf is effective only if libunwind (or a recent version
of libdw) is present on the system; the value lbr only works for
certain cpus. The method for kernel space is controlled not by this
option but by the kernel config (CONFIG_UNWINDER_*).

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.

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

report.skip-empty
This option can change default stat behavior with empty results. If
it’s set true, perf report --stat will not show 0 stats.

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.

top.call-graph
This is identical to call-graph.record-mode, except it is
applicable only for top subcommand. This option ONLY setup the
unwind method. To enable perf top to actually use it, the command
line option -g must be specified.

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, skip or mmap. 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. mmap skips
post-processing and reads build-ids from MMAP events.

record.call-graph
This is identical to call-graph.record-mode, except it is
applicable only for record subcommand. This option ONLY setup the
unwind method. To enable perf record to actually use it, the
command line option -g must be specified.

record.aio
Use n control blocks in asynchronous (Posix AIO) trace writing mode
(n default: 1, max: 4).

record.debuginfod
Specify debuginfod URL to be used when cacheing perf.data binaries,
it follows the same syntax as the DEBUGINFOD_URLS variable, like:

http://192.168.122.174:8002

If the URLs is 'system', the value of DEBUGINFOD_URLS system environment
variable is used.

diff.*, diff.order
This option sets the number of columns to sort the result. The
default is 0, which means sorting by baseline. Setting it to 1 will
sort the result by delta (or other compute method selected).

diff.compute
This options sets the method for computing the diff result.
Possible values are delta, delta-abs, ratio and wdiff. Default is
delta.

trace.*, trace.add_events
Allows adding a set of events to add to the ones specified by the
user, or use as a default one if none was specified. The initial
use case is to add augmented_raw_syscalls.o to activate the perf
trace logic that looks for syscall pointer contents after the
normal tracepoint payload.

trace.args_alignment
Number of columns to align the argument list, default is 70, use 40
for the strace default, zero to no alignment.

trace.no_inherit
Do not follow children threads.

trace.show_arg_names
Should syscall argument names be printed? If not then
trace.show_zeros will be set.

trace.show_duration
Show syscall duration.

trace.show_prefix
If set to yes will show common string prefixes in tables. The
default is to remove the common prefix in things like "MAP_SHARED",
showing just "SHARED".

trace.show_timestamp
Show syscall start timestamp.

trace.show_zeros
Do not suppress syscall arguments that are equal to zero.

trace.tracepoint_beautifiers
Use "libtraceevent" to use that library to augment the tracepoint
arguments, "libbeauty", the default, to use the same argument
beautifiers used in the strace-like sys_enter+sys_exit lines.

ftrace.*, ftrace.tracer
Can be used to select the default tracer when neither -G nor -F
option is not specified. Possible values are function and
function_graph.

samples.*, samples.context
Define how many ns worth of time to show around samples in perf
report sample context browser.

scripts.*
Any option defines a script that is added to the scripts menu in
the interactive perf browser and whose output is displayed. The
name of the option is the name, the value is a script command line.
The script gets the same options passed as a full perf script, in
particular -i perfdata file, --cpu, --tid

convert.*, convert.queue-size
Limit the size of ordered_events queue, so we could control
allocation size of perf data files without proper finished round
events.

stat.*, stat.big-num
(boolean) Change the default for "--big-num". To make
"--no-big-num" the default, set "stat.big-num=false".

intel-pt.*, intel-pt.cache-divisor, intel-pt.mispred-all
If set, Intel PT decoder will set the mispred flag on all branches.

intel-pt.max-loops
If set and non-zero, the maximum number of unconditional branches
decoded without consuming any trace packets. If the maximum is
exceeded there will be a "Never-ending loop" error. The default is
100000.

auxtrace.*, auxtrace.dumpdir
s390 only. The directory to save the auxiliary trace buffer can be
changed using this option. Ex, auxtrace.dumpdir=/tmp. If the
directory does not exist or has the wrong file type, the current
directory is used.

itrace.*, debug-log-buffer-size
Log size in bytes to output when using the option --itrace=d+e
Refer itrace option of perf-script(1) or perf-report(1). The
default is 16384.

daemon.*, daemon.base
Base path for daemon data. All sessions data are stored under this
path.

session-<NAME>.*, session-<NAME>.run
Defines new record session for daemon. The value is record’s
command line without the record keyword.