perf-config(1) — Linux manual page

NAME \| SYNOPSIS \| DESCRIPTION \| OPTIONS \| CONFIGURATION FILE \| SEE ALSO \| COLOPHON

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

NAME top

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

SYNOPSIS top

       perf config [<file-option>] [section.name[=value] ...]
       or
       perf config [<file-option>] -l | --list

DESCRIPTION top

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

OPTIONS top

       -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 top

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.

COLOPHON top

       This page is part of the perf (Performance analysis tools for
       Linux (in Linux source tree)) project.  Information about the
       project can be found at 
       ⟨https://perf.wiki.kernel.org/index.php/Main_Page⟩.  If you have a
       bug report for this manual page, send it to
       [email protected].  This page was obtained from the
       project's upstream Git repository
       ⟨http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git⟩
       on 2024-06-14.  (At that time, the date of the most recent commit
       that was found in the repository was 2024-06-13.)  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to [email protected]

perf                           2023-11-27                 PERF-CONFIG(1)

Pages that refer to this page: perf(1), perf-daemon(1), perf-intel-pt(1)

perf-config(1) — Linux manual page

NAME top

SYNOPSIS top

DESCRIPTION top

OPTIONS top

CONFIGURATION FILE top

SEE ALSO top

COLOPHON top