perf-config(1) ============== NAME ---- perf-config - Get and set variables in a configuration file. SYNOPSIS -------- [verse] 'perf config' [] -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 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 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..cmd' or use different path using 'man..path' config option. pager.*:: pager.:: 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]