Date:	Sun, 12 Jun 2016 17:57:28 +0900
From:	Taeung Song <treeze.taeung@...il.com>
To:	Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>
Cc:	linux-kernel@...r.kernel.org, Jiri Olsa <jolsa@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Ingo Molnar <mingo@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Masami Hiramatsu <mhiramat@...nel.org>,
	Wang Nan <wangnan0@...wei.com>, Jiri Olsa <jolsa@...hat.com>,
	Ingo Molnar <mingo@...hat.com>
Subject: Re: [PATCH v8 3/5] perf config: Reimplement perf_config() using
 perf_config_set__iter()

Hi, Arnaldo

What do you think about setting all actual config variables
before a sub-command start at perf.c ?

(in order to free the config set that contains all configs
by perf_config_set__delete() after using it was finished where it was 
needed)

i.e. initialize all actual config variables at perf.c
instead of at each source file as below.
(before running a particular sub-command at run_builitin())

util/alias.c
22:	perf_config(alias_lookup_cb, NULL);

util/intel-pt.c
330:	perf_config(intel_pt_config_div, &d);
1993:static int intel_pt_perf_config(const char *var, const char *value, 
void *data)
2047:	perf_config(intel_pt_perf_config, pt);

util/data-convert-bt.c
1302:	perf_config(convert__config, &c);

util/help-unknown-cmd.c
62:	perf_config(perf_unknown_cmd_config, NULL);

builtin-help.c
454:	perf_config(perf_help_config, &help_format);

perf.c
94:	perf_config(pager_command_config, &c);
117:	perf_config(browser_command_config, &c);
561:	perf_config(perf_default_config, NULL);

builtin-record.c
1432:	perf_config(perf_record_config, rec);

ui/browsers/annotate.c
1163:	perf_config(annotate__config, NULL);

ui/browser.c
743:	perf_config(ui_browser__color_config, NULL);

builtin-report.c
829:	perf_config(report__config, &report);

builtin-kmem.c
1899:	perf_config(kmem_config, NULL);

builtin-top.c
1231:	perf_config(perf_top_config, &top);


If we do, we could set all actual config variables
before a sub-command work. And the config set that is made
by perf_config_set__new() would be reused
when we initialize all actual config variables
and then if using is is finished, we could free the config set.


Thanks,
Taeung


On 06/10/2016 07:58 PM, Taeung Song wrote:
>
>
> On 06/09/2016 10:34 PM, Arnaldo Carvalho de Melo wrote:
>> Em Wed, Jun 08, 2016 at 09:36:51PM +0900, Taeung Song escreveu:
>>> Many sub-commands use perf_config() so
>>> everytime perf_config() is called, perf_config() always read config
>>> files.
>>> (i.e. user config '~/.perfconfig' and system config
>>> '$(sysconfdir)/perfconfig')
>>
>> And this is not always a bad thing, think about being in 'mutt' and
>> adding an entry to ~/.mail_aliases, then going to compose a message,
>> would be good that the just added entry to ~/.mail_aliases be considered
>> when adding recipients to your messages, right?
>>
>> In the same fashion, 'perf report', 'perf annotate', 'perf top' are long
>> running utilities that have operations that could get changes to config
>> files without having to restart them, i.e. do annotation changes in your
>> ~/.perfconfig and then see them reflected next time you hit 'A´ to
>> annotate a function in 'perf top' or 'perf report'.
>>
>
> Currently, this suggestion isn't already contained among features of
> perf. right?
>
> I understood that you mean while perf process is already running
> if user change a config file, the changed config can be reflected in
> 'perf top', 'perf report' or etc without restarting perf process like mutt.
> Is it right ?
>
>> So, I think that if tools want ammortize the cost of reading config
>> files, they should create an instance of the relevant object
>> (perf_config_set?) use it and then delete it, but not keep one around
>> for a long time.
>>
>
> I got it.
>
> How about the two ideas that I have in mind ?
>
> 1) If we eliminate the config set object(perf_config_set) after using it
> because we don't need to keep it until perf process is done,
>
> we could bring many codes using perf_config() at one spot of perf.c ?
> (because it is hard to decide a point of time we destroy the config set.)
> For example,
>
> (This code isn't executable)
>
> diff --git a/tools/perf/perf.c b/tools/perf/perf.c
> index 15982ce..6a56985 100644
> --- a/tools/perf/perf.c
> +++ b/tools/perf/perf.c
> @@ -77,6 +77,23 @@ struct pager_config {
>           int val;
>   };
>
> +static void perf_default_config_init(void)
> +{
> +        default_colors_config_init();
> +        default_annoate_config_init();
> +        default_report_config_init();
> +        ...
> +}
> +
> +static void perf_config_init(void)
> +{
> +        perf_default_config_init();
> +        colors_config_init();
> +        annotate_config_init();
> +        report_config_init();
> +        ...
> +}
> +
>   static int pager_command_config(const char *var, const char *value,
> void *data)
>   {
>           struct pager_config *c = data;
> @@ -558,7 +575,7 @@ int main(int argc, const char **argv)
>
>           srandom(time(NULL));
>
> -        perf_config(perf_default_config, NULL);
> +        perf_config_init();
>           set_buildid_dir(NULL);
>
>           /* get debugfs/tracefs mount point from /proc/mounts */
> diff --git a/tools/perf/ui/browser.c b/tools/perf/ui/browser.c
> index af68a9d..4b827c2 100644
> --- a/tools/perf/ui/browser.c
> +++ b/tools/perf/ui/browser.c
> @@ -740,8 +740,6 @@ void ui_browser__init(void)
>   {
>           int i = 0;
>
> -        perf_config(ui_browser__color_config, NULL);
> -
>           while (ui_browser__colorsets[i].name) {
>                   struct ui_browser_colorset *c =
> &ui_browser__colorsets[i++];
>                   sltt_set_color(c->colorset, c->name, c->fg, c->bg);
>
> ... (omitted)
>
>
> Many sub-commands call perf_config() at builtin-report.c, ui/browser.c
> and etc. So I think it is ambiguous to decide where
> perf_config_set__delete()
> will be called instead of at run_builtin().
>
> (If the config set's life cycle is the same as perf's ,
> I would call perf_config_set__delete() at run_builtin()
> because a sub-command is done)
>
>
> 2) If having the config set for perf's life,
>
> we would add configuration features to TUI like TUI configuring options
> for linux kernel compiling (e.g. make menuconfig) ?
>
> Of course, we don't need to have the same function as make menuconfig
> but IMHO, we could add similar way to menuconfig while perf is running.
>
>
> How do you feel about these ?
>
>
> Thanks, :)
> Taeung
>
>>
>>> But we need to use the config set that already contains all config
>>> key-value pairs to avoid this repetitive work reading the config files
>>> in perf_config(). (the config set mean a global variable 'config_set')
>>>
>>> In other words, if new perf_config() is called,
>>> only first time 'config_set' is initialized collecting all configs
>>> from the config files and it work with perf_config_set__iter().
>>> And free the config set after a sub-command work at run_builtin().
>>>
>>> If we do, 'config_set' can be reused wherever using perf_config()
>>> and a feature of old perf_config() is the same as new perf_config() work
>>> without the repetitive work that read the config files.
>>>
>>> Cc: Namhyung Kim <namhyung@...nel.org>
>>> Cc: Jiri Olsa <jolsa@...hat.com>
>>> Cc: Wang Nan <wangnan0@...wei.com>
>>> Cc: Peter Zijlstra <peterz@...radead.org>
>>> Cc: Ingo Molnar <mingo@...hat.com>
>>> Cc: Masami Hiramatsu <mhiramat@...nel.org>
>>> Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
>>> Signed-off-by: Taeung Song <treeze.taeung@...il.com>
>>> ---
>>>   tools/perf/builtin-config.c |  4 +++
>>>   tools/perf/perf.c           |  1 +
>>>   tools/perf/util/config.c    | 87
>>> ++++++++++++++++++++++-----------------------
>>>   tools/perf/util/config.h    |  1 +
>>>   4 files changed, 48 insertions(+), 45 deletions(-)
>>>
>>> diff --git a/tools/perf/builtin-config.c b/tools/perf/builtin-config.c
>>> index fe1b77f..cfd1036 100644
>>> --- a/tools/perf/builtin-config.c
>>> +++ b/tools/perf/builtin-config.c
>>> @@ -80,6 +80,10 @@ int cmd_config(int argc, const char **argv, const
>>> char *prefix __maybe_unused)
>>>       else if (use_user_config)
>>>           config_exclusive_filename = user_config;
>>>
>>> +    /*
>>> +     * At only 'config' sub-command, individually use the config set
>>> +     * because of reinitializing with options config file location.
>>> +     */
>>>       set = perf_config_set__new();
>>>       if (!set) {
>>>           ret = -1;
>>> diff --git a/tools/perf/perf.c b/tools/perf/perf.c
>>> index 15982ce..fe2ab7c 100644
>>> --- a/tools/perf/perf.c> - Arnaldo
>>> +++ b/tools/perf/perf.c
>>> @@ -391,6 +391,7 @@ static int run_builtin(struct cmd_struct *p, int
>>> argc, const char **argv)
>>>
>>>       perf_env__set_cmdline(&perf_env, argc, argv);
>>>       status = p->fn(argc, argv, prefix);
>>> +    perf_config_set__delete(config_set);
>>>       exit_browser(status);
>>>       perf_env__exit(&perf_env);
>>>       bpf__clear();
>>> diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
>>> index 31e09a4..72db134 100644
>>> --- a/tools/perf/util/config.c
>>> +++ b/tools/perf/util/config.c
>>> @@ -28,6 +28,7 @@ static int config_linenr;
>>>   static int config_file_eof;
>>>
>>>   const char *config_exclusive_filename;
>>> +struct perf_config_set *config_set;
>>>
>>>   static int get_next_char(void)
>>>   {
>>> @@ -478,51 +479,6 @@ static int perf_config_global(void)
>>>       return !perf_env_bool("PERF_CONFIG_NOGLOBAL", 0);
>>>   }
>>>
>>> -int perf_config(config_fn_t fn, void *data)
>>> -{
>>> -    int ret = -1;
>>> -    const char *home = NULL;
>>> -
>>> -    /* Setting $PERF_CONFIG makes perf read _only_ the given config
>>> file. */
>>> -    if (config_exclusive_filename)
>>> -        return perf_config_from_file(fn, config_exclusive_filename,
>>> data);
>>> -    if (perf_config_system() && !access(perf_etc_perfconfig(), R_OK)) {
>>> -        if (perf_config_from_file(fn, perf_etc_perfconfig(), data) < 0)
>>> -            goto out;
>>> -    }
>>> -
>>> -    home = getenv("HOME");
>>> -    if (perf_config_global() && home) {
>>> -        char *user_config = strdup(mkpath("%s/.perfconfig", home));
>>> -        struct stat st;
>>> -
>>> -        if (user_config == NULL) {
>>> -            warning("Not enough memory to process %s/.perfconfig, "
>>> -                "ignoring it.", home);
>>> -            goto out;
>>> -        }
>>> -
>>> -        if (stat(user_config, &st) < 0)
>>> -            goto out_free;
>>> -
>>> -        if (st.st_uid && (st.st_uid != geteuid())) {
>>> -            warning("File %s not owned by current user or root, "
>>> -                "ignoring it.", user_config);
>>> -            goto out_free;
>>> -        }
>>> -
>>> -        if (!st.st_size)
>>> -            goto out_free;
>>> -
>>> -        ret = perf_config_from_file(fn, user_config, data);
>>> -
>>> -out_free:
>>> -        free(user_config);
>>> -    }
>>> -out:
>>> -    return ret;
>>> -}
>>> -
>>>   static struct perf_config_section *find_section(struct list_head
>>> *sections,
>>>                           const char *section_name)
>>>   {
>>> @@ -706,6 +662,47 @@ struct perf_config_set *perf_config_set__new(void)
>>>       return set;
>>>   }
>>>
>>> +static int perf_config_set__iter(struct perf_config_set *set,
>>> config_fn_t fn, void *data)
>>> +{
>>> +    struct perf_config_section *section;
>>> +    struct perf_config_item *item;
>>> +    struct list_head *sections;
>>> +    char key[BUFSIZ];
>>> +
>>> +    if (set == NULL)
>>> +        return -1;
>>> +
>>> +    sections = &set->sections;
>>> +    if (list_empty(sections))
>>> +        return -1;
>>> +
>>> +    list_for_each_entry(section, sections, node) {
>>> +        list_for_each_entry(item, &section->items, node) {
>>> +            char *value = item->value;
>>> +
>>> +            if (value) {
>>> +                scnprintf(key, sizeof(key), "%s.%s",
>>> +                      section->name, item->name);
>>> +                if (fn(key, value, data) < 0) {
>>> +                    pr_err("Error: wrong config key-value pair
>>> %s=%s\n",
>>> +                           key, value);
>>> +                    return -1;
>>> +                }
>>> +            }
>>> +        }
>>> +    }
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +int perf_config(config_fn_t fn, void *data)
>>> +{
>>> +    if (config_set == NULL)
>>> +        config_set = perf_config_set__new();
>>> +
>>> +    return perf_config_set__iter(config_set, fn, data);
>>> +}
>>> +
>>>   static void perf_config_item__delete(struct perf_config_item *item)
>>>   {
>>>       zfree(&item->name);
>>> diff --git a/tools/perf/util/config.h b/tools/perf/util/config.h
>>> index 35ccddb..7cc4fea 100644
>>> --- a/tools/perf/util/config.h
>>> +++ b/tools/perf/util/config.h
>>> @@ -21,6 +21,7 @@ struct perf_config_set {
>>>   };
>>>
>>>   extern const char *config_exclusive_filename;
>>> +extern struct perf_config_set *config_set;
>>>
>>>   typedef int (*config_fn_t)(const char *, const char *, void *);
>>>   int perf_default_config(const char *, const char *, void *);
>>> --
>>> 2.5.0

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