perf-config(1) — Linux manual page


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

DESCRIPTION         top

       You can manage variables in a configuration file with this

OPTIONS         top

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

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

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


       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.

       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:

                   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

       Given a $HOME/.perfconfig like this:

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

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

                   # Defaults if linked with libslang
                   report = on
                   annotate = on
                   top = on

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

                   # Defaults
                   hide_src_code = false
                   use_offset = true
                   jump_arrows = true
                   show_nr_jumps = false

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

                   show-headers = true

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

                   # 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

           % perf config 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

           % 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

           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
           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.

           medium means a overhead percentage which has more than 0.5%.
           Default values are green and default.

           normal means the rest of overhead percentages except top,
           medium, selected. Default values are lightgray and default.

           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 for jump arrows on assembly code listings such as jns,
           jmp, jane, etc. Default values are blue, default.

           This selects colors for addresses from annotate. Default
           values are magenta, default.

           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:

                       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 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.debuginfod=URLs Specify debuginfod URLs to be
           used when retrieving binaries, it follows the same
           syntax as the DEBUGINFOD_URLS variable, like:


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

           addr2line binary to use for file names and line numbers.

           objdump binary to use for disassembly and annotations.

           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.

           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.

           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.

           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

               │     ┌──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.

           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.

           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.

           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.

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

                74.03 │      mov    %fs:0x28,%rax

               When set as true:

                    6 │      mov    %fs:0x28,%rax

               This option works with tui, stdio2, stdio browsers.

           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.

           Demangle symbol names to human readable form. Default is

           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%).

           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.

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

           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

           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.

           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

               Overhead  Symbols
               ........  .......
                 40.00%  foo
                            |          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.

           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'.

           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.

           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

           This is a maximum number of lines of callchain printed for a
           single histogram entry. Default is 0 which means no

       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.

           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.

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

           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.
           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         [.] strcmp
                    0.03%   0.00%  noploop  [kernel.kallsyms]  [k] timerqueue_del

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

       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.
           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

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

           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.
           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.

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

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


               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

           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.

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

           Do not follow children threads.

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

           Show syscall duration.

           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".

           Show syscall start timestamp.

           Do not suppress syscall arguments that are equal to zero.

           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

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

           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,

       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

           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.

SEE ALSO         top


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 
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       bug report for this manual page, send it to  This page was obtained from the
       project's upstream Git repository
       on 2023-12-22.  (At that time, the date of the most recent commit
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       manual page), send a mail to

perf                           2023-08-15                 PERF-CONFIG(1)

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