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 command.

OPTIONS         top

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

           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.

       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

       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 lines.

       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

       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 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

           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

               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.

       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

           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.

           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;

           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

               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

           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

           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++;
               │             }

           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)

           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

           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.

       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.

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

           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.

           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 example.

               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

           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.

           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.

           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

           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

       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.

           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.

       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).

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

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 ⟨⟩.  If
       you have a bug report for this manual page, send it to  This page was obtained from the
       project's upstream Git repository
       ⟨⟩ on
       2018-10-29.  (At that time, the date of the most recent commit that
       was found in the repository was 2018-10-27.)  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

perf                             04/30/2018                   PERF-CONFIG(1)