Date:	Thu, 1 Oct 2015 14:24:20 +0900
From:	Taeung Song <treeze.taeung@...il.com>
To:	Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	jolsa@...hat.com, namhyung@...nel.org,
	Ingo Molnar <mingo@...hat.com>
Subject: Re: [PATCH v6 1/7] perf tools: Add 'perf-config' command

Hi, Arnaldo

Thanks for your review


> On Sep 28, 2015, at 11:01 PM, Arnaldo Carvalho de Melo <arnaldo.melo@...il.com> wrote:
> 
> Em Wed, Sep 23, 2015 at 03:57:01PM +0900, Taeung Song escreveu:
>> The perf configuration file contains many variables which can make
>> the perf command's action more effective.
>> But looking through state of configuration is difficult and there's no knowing
>> what kind of other variables except variables in perfconfig.example exist.
>> So This patch adds 'perf-config' command with '--list' option and a document for it.
>> 
>>    perf config [options]
>> 
>>    display current perf config variables.
>>    # perf config
>>    or
>>    # perf config -l | --list
>> 
>> Signed-off-by: Taeung Song <treeze.taeung@...il.com>
>> ---
>> tools/perf/Build                         |   1 +
>> tools/perf/Documentation/perf-config.txt | 381 +++++++++++++++++++++++++++++++
>> tools/perf/builtin-config.c              |  62 +++++
>> tools/perf/builtin.h                     |   1 +
>> tools/perf/command-list.txt              |   1 +
>> tools/perf/perf.c                        |   1 +
>> 6 files changed, 447 insertions(+)
>> create mode 100644 tools/perf/Documentation/perf-config.txt
>> create mode 100644 tools/perf/builtin-config.c
>> 
>> diff --git a/tools/perf/Build b/tools/perf/Build
>> index 7223745..2c7aaf2 100644
>> --- a/tools/perf/Build
>> +++ b/tools/perf/Build
>> @@ -1,5 +1,6 @@
>> perf-y += builtin-bench.o
>> perf-y += builtin-annotate.o
>> +perf-y += builtin-config.o
>> perf-y += builtin-diff.o
>> perf-y += builtin-evlist.o
>> perf-y += builtin-help.o
>> diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt
>> new file mode 100644
>> index 0000000..a3a12cc
>> --- /dev/null
>> +++ b/tools/perf/Documentation/perf-config.txt
>> @@ -0,0 +1,381 @@
>> +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 with key and value into each sections.
> 
>   Show current config variables, name and value, for all sections.
> 
>> +
>> +CONFIGURATION FILE
>> +------------------
>> +
>> +The Perf configuration file contains many variables which can make
>> +the perf command's action more effective.
>> +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.
>> +
>> +The variables are divided into sections. In each section, the variables
>> +can are composed of a key and value.
> 
> "can are" -> "that are"
> 
>> +
>> +Syntax
>> +~~~~~~
>> +
>> +The file consists of sections and names. A section begins with
>> +the name of the section in square brackets and continues until the next
> 
> The file consists of sections. A section startas with its name
> surrounded by square brackers and continues till the next section
> begins.
> 
>> +section begins. Each variable have to belong to some section, which means
>> +there must be a section header before the first setting of a variable, as below:
> 
> Each variable belongs to a section, which means that there must be a
> section header before the first variable, as below:
> 
>> +Each variable are in the form 'name = value'.
>> +
>> +	[section]
>> +		name1 = value1
>> +		name2 = value2
>> +
>> +Section names are case sensitive and can contain any characters except
>> +newline (doublequote `"` and backslash have to be escaped as `\"` and `\\`,
> 
>  double quote
> 
>> +respectively).  Section headers can't span multiple
>> +lines.  Variables may belong directly to a section.
> 
> ? They "may" or they "must"? what means "belong directly to a section”?

I meant a section can contain variables or not.
But I think the sentence "Variables may belong directly to a section” isn’t needed.

> 
>> +
>> +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
>> +	code = 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.*::
>> +	Color variables can customize colors of the output which is printed out
>> +	from ‘report’, ‘top’, ’annotate’ on tui.
>> +	Color variables are composed of foreground and background
>> +	and should have two values for them. If you want to keep as colors
> 
> "and should have two values, comma separated. (please provide an example
> of setting one of those variables).
> 
>> +	of your terminal, you should use ‘default’ for the color value.
> 
> If you want to keep the background or the foreground color set for your
> terminal, replace the desired value with 'default'. For instance:
> 
> (provide an example of setting just the foreground or the background,
> with 'default' for the terminal color that should be used
> 
>> +	The color names that can be used are:
> 
> Shorter:
> 
> "Avaliable colors:"
> 
>> +	red, green, default, black, blue, white, magenta, lightgray
>> +
>> +	colors.top::
>> +		‘top’ means a overhead percentage which is more than 5%.
>> +		And values of this variable specify colors of percentage.
>> +		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 ’white’ and ’lightgray’.
>> +	colors.code::
>> +		Colors for arrows and lines in jumps 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-command ‘top’.
>> +		Default values are ‘white’, ‘blue’.
>> +
>> +tui.*::
>> +	A boolean value that controls launching TUI browser for each subcommand.
> 
>        A boolean value that controls if the TUI browser will be used
> for subcomands having that UI.
> 
>> +	By default, TUI is enabled if perf detects the required library during build
>> +	and this config option can control it.  Available subcommands are 'top',
>> +	'report' and 'annotate'.
>> +
>> +gtk.*::
>> +	A boolean value that controls launching GTK+2 GUI browser for
>> +	each subcommand.  By default, TUI is enabled if perf detects the
> 
> Use TUI wording suggested above
> 
>> +	required library during build and this config option can control it.
>> +	Available subcommands are 'top', 'report' and 'annotate'.
>> +
>> +buildid.*::
>> +	buildid.dir::
>> +		Each executable or shared library built with each program is assigned
>> +		a unique identification as build-id. The option means a path where
>> +		build-id information can be saved.
> 
> Each executable and shared library in modern distributions comes with a
> content based identified 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 anotation, etc.
> 
> The recording tools also stores a hard link or copy in a per-user
> directory, $HOME/.debug/, of binaries, shared libraries, /proc/kallsyms
> and /proc/kcore files to be used at analysis time.
> 
> The buildid.dir variable can be used to either change this directory
> cache location, or to disable it altogether.
> 
> ---
> find out how to disable it, iirc, its a matter of testing if setting
> buildid.dir to /dev/null works
> Yeah, it works:
> 
> [acme@zoo linux]$ ls -la ~/.debug/
> ls: cannot access /home/acme/.debug/: No such file or directory
> [acme@zoo linux]$ perf record usleep 1
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.016 MB perf.data (7 samples) ]
> [acme@zoo linux]$ ls -la ~/.debug/
> ls: cannot access /home/acme/.debug/: No such file or directory
> [acme@zoo linux]$ cat ~/.perfconfig 
> [buildid]
> 	dir = /dev/null
> [acme@zoo linux]$

So.. setting buildid.dir to /dev/null hasn’t problems ?
Do I just add a description to disable it by ‘/dev/null’ ?  

Thanks,
Taeung

> 
>> +		The default is $HOME/.debug
>> +
>> +annotate.*::
>> +	There’re options which work with a ’annotate’ sub-command.
>> +	This options is 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 of itself,
> 
> No need for "of itself"
> 
>> +		this option let ‘annotate’ print a list of assembly code with the source code.
>                            lets          to print
> 
> Getting sidetracked, hope this helps.
> 
> - Arnaldo
> 
>> +		For example, let’s see a part of a program. There’re four lines.
>> +		If this option is ‘false’, 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 ‘true’, source code of the part
>> +		can be also printed as below.
>> +
>> +		│      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 a example.
>> +		If a base address is 0XFFFFFFFF81624d50 as below,
>> +
>> +		ffffffff81624d50 <load0>
>> +
>> +		a address on assembly code has a specific absolute address as below
>> +
>> +		ffffffff816250b8:│  mov    0x8(%r14),%rdi
>> +
>> +		but if use_offset is ’true’, a address subtracted from a base address is printed.
>> +		The default is true.
>> +
>> +		             368:│  mov    0x8(%r14),%rdi
>> +
>> +	annotate.jump_arrows::
>> +		There’re 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.
>> +
>> +		│      ↓ jmp    1333
>> +		│        xchg   %ax,%ax
>> +		│1330:   mov    %r15,%r10
>> +		│1333:   cmp    %r15,%r14
>> +
>> +        annotate.show_nr_jumps::
>> +		Let’s see a part of assembly code.
>> +
>> +		│1382:   movb   $0x1,-0x270(%rbp)
>> +
>> +		If use this, the number of branches branching to that address can be printed as below.
>> +
>> +		│1 1382:   movb   $0x1,-0x270(%rbp)
>> +
>> +help.*::
>> +	help.format:: = man
>> +		A format of manual page can be ‘man’, ‘info’, ‘web’ or ‘html’.
>> +		’man’ is default.
>> +	help.autocorrect:: = 0
>> +		Automatically correct and execute mistyped commands after
>> +		waiting for the given number of deciseconds (0.1 sec).
>> +		Let's see a example. If a mistyped sub-command is executed like 'perf mistyped-command'
>> +		and this option is 0, the output is as below.
>> +
>> +		perf: 'mistyped-command' is not a perf-command. See 'perf --help’.
>> +
>> +		Or if this option is more than 1, the output can be such as.
>> +
>> +		WARNING: You called a perf program named 'mistyped-command', which does not exist.
>> +		Continuing under the assumption that you meant 'with-kcore'
>> +		in 0.1 seconds automatically...
>> +		Usage: perf-with-kcore <perf sub-command> <perf.data directory> [<sub-command options> [ -- <workload>]]
>> +		<perf sub-command> can be record, script, report or inject
>> +		    or: perf-with-kcore fix_buildid_cache_permissions
>> +
>> +hist.*::
>> +	hist.percentage::
>> +		This option control a way to calcurate 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::
>> +		There’re columns as header ‘Overhead’, ‘Children’, ‘Shared Object’, ‘Symbol’, ’self’.
>> +		If this option is false, they are hiden.
>> +
>> +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) and ‘dwarf’.
>> +		The value of 'dwarf' is effective only if perf detect needed library
>> +		(libunwind or a recent version of libdw).  Also it doesn't *require*
>> +		the dump-size option since it can use the default value of 8192 if
>> +		missing.
>> +
>> +	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 this option should have a value.
>> +
>> +	call-graph.print-type::
>> +		The print-types can be graph (graph absolute), fractal (graph relative), flat.
>> +		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 default format which is 'fractal'.  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.
>> +
>> +	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.
>> +
>> +	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 threashold.  Default is 0.5 (%).
>> +
>> +	call-graph.print-limit::
>> +		This is another way to control the number of callchains printed for a
>> +		single entry.  Default is 0 which means no limitation.
>> +
>> +report.*::
>> +	report.percent-limit::
>> +		This one is mostly same as call-graph.threshold but works for
>> +		histogram entries.  Entries have overhead lower than this percentage
>> +		will not be printed.  Default is 0.
>> +		If percent-limit is 70, the output which has percentages of
>> +		each overhead above 70% can be printed.
>> +
>> +	report.queue-size::
>> +		option to setup the maximum allocation size for session's
>> +		ordered events queue, if not set there's no default limit.
>> +
>> +	report.children::
>> +		The children means that functions called from another function.
>> +		If the option is true, accumulate callchain of children and show total overhead.
>> +		Please refer to the perf-report manual.
>> +
>> +top.*::
>> +	top.children::
>> +		This option means same as report.children.
>> +		So it is true, the output of ‘top’ is rearranged by each overhead into children group.
>> +
>> +man.*::
>> +	man.viewer::
>> +		This option can assign a manual tool with which a subcommand 'help' work.
>> +		it can used as 'man', 'woman', 'konqueror'. Default value is 'man'.
>> +
>> +pager.*::
>> +	pager.<subcommand>::
>> +		When a subcommand work as stdio instead of TUI, use pager with it.
>> +		Default value is 'true'.
>> +
>> +kmem.*::
>> +	kmem.default::
>> +		This option can decide which allocator is analyzed between 'slab' and 'page'
>> +		without using options '--slab' and '--page'.
>> +		Default value is 'slab'.
>> +
>> +SEE ALSO
>> +--------
>> +linkperf:perf[1], linkperf:perf-report[1]
>> diff --git a/tools/perf/builtin-config.c b/tools/perf/builtin-config.c
>> new file mode 100644
>> index 0000000..30b1500
>> --- /dev/null
>> +++ b/tools/perf/builtin-config.c
>> @@ -0,0 +1,62 @@
>> +/*
>> + * builtin-config.c
>> + *
>> + * Copyright (C) 2015, Taeung Song <treeze.taeung@...il.com>
>> + *
>> + */
>> +#include "builtin.h"
>> +
>> +#include "perf.h"
>> +
>> +#include "util/cache.h"
>> +#include "util/parse-options.h"
>> +#include "util/util.h"
>> +#include "util/debug.h"
>> +
>> +static const char * const config_usage[] = {
>> +	"perf config [options]",
>> +	NULL
>> +};
>> +
>> +enum actions {
>> +	ACTION_LIST = 1
>> +} actions;
>> +
>> +static struct option config_options[] = {
>> +	OPT_GROUP("Action"),
>> +	OPT_SET_UINT('l', "list", &actions,
>> +		     "show current config variables", ACTION_LIST),
>> +	OPT_END()
>> +};
>> +
>> +static int show_config(const char *key, const char *value,
>> +		       void *cb __maybe_unused)
>> +{
>> +	if (value)
>> +		printf("%s=%s\n", key, value);
>> +	else
>> +		printf("%s\n", key);
>> +
>> +	return 0;
>> +}
>> +
>> +int cmd_config(int argc, const char **argv, const char *prefix __maybe_unused)
>> +{
>> +	int ret = 0;
>> +
>> +	argc = parse_options(argc, argv, config_options, config_usage,
>> +			     PARSE_OPT_STOP_AT_NON_OPTION);
>> +
>> +	switch (actions) {
>> +	case ACTION_LIST:
>> +	default:
>> +		if (argc) {
>> +			pr_err("Error: takes no arguments\n");
>> +			parse_options_usage(config_usage, config_options, "l", 1);
>> +			return -1;
>> +		} else
>> +			ret = perf_config(show_config, NULL);
>> +	}
>> +
>> +	return ret;
>> +}
>> diff --git a/tools/perf/builtin.h b/tools/perf/builtin.h
>> index 3688ad2..3f871b5 100644
>> --- a/tools/perf/builtin.h
>> +++ b/tools/perf/builtin.h
>> @@ -17,6 +17,7 @@ extern int cmd_annotate(int argc, const char **argv, const char *prefix);
>> extern int cmd_bench(int argc, const char **argv, const char *prefix);
>> extern int cmd_buildid_cache(int argc, const char **argv, const char *prefix);
>> extern int cmd_buildid_list(int argc, const char **argv, const char *prefix);
>> +extern int cmd_config(int argc, const char **argv, const char *prefix);
>> extern int cmd_diff(int argc, const char **argv, const char *prefix);
>> extern int cmd_evlist(int argc, const char **argv, const char *prefix);
>> extern int cmd_help(int argc, const char **argv, const char *prefix);
>> diff --git a/tools/perf/command-list.txt b/tools/perf/command-list.txt
>> index 00fcaf8..acc3ea7 100644
>> --- a/tools/perf/command-list.txt
>> +++ b/tools/perf/command-list.txt
>> @@ -9,6 +9,7 @@ perf-buildid-cache		mainporcelain common
>> perf-buildid-list		mainporcelain common
>> perf-data			mainporcelain common
>> perf-diff			mainporcelain common
>> +perf-config			mainporcelain common
>> perf-evlist			mainporcelain common
>> perf-inject			mainporcelain common
>> perf-kmem			mainporcelain common
>> diff --git a/tools/perf/perf.c b/tools/perf/perf.c
>> index 1fded92..6acbfd5 100644
>> --- a/tools/perf/perf.c
>> +++ b/tools/perf/perf.c
>> @@ -38,6 +38,7 @@ struct cmd_struct {
>> static struct cmd_struct commands[] = {
>> 	{ "buildid-cache", cmd_buildid_cache, 0 },
>> 	{ "buildid-list", cmd_buildid_list, 0 },
>> +	{ "config",	cmd_config,	0 },
>> 	{ "diff",	cmd_diff,	0 },
>> 	{ "evlist",	cmd_evlist,	0 },
>> 	{ "help",	cmd_help,	0 },
>> -- 
>> 1.9.1

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