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Date: Fri, 18 Mar 2016 09:52:10 +0900
From: Taeung Song <treeze.taeung@...il.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>,
linux-kernel@...r.kernel.org, Jiri Olsa <jolsa@...nel.org>,
Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH v2 1/5] perf config: Introduce perf_config_set class
On 03/18/2016 08:27 AM, Namhyung Kim wrote:
> On Thu, Mar 17, 2016 at 11:10:12PM +0900, Taeung Song wrote:
>> Hi, Namhyung
>>
>> On 03/17/2016 09:31 PM, Namhyung Kim wrote:
>>> Hi Taeung,
>>>
>>> On Mon, Mar 14, 2016 at 09:16:05PM +0900, Taeung Song wrote:
>>>> This infrastructure code was designed for
>>>> upcoming features of perf-config.
>>>>
>>>> That collect config key-value pairs from user and
>>>> system config files (i.e. user wide ~/.perfconfig
>>>> and system wide $(sysconfdir)/perfconfig)
>>>> to manage perf's configs.
>>>>
>>>> Cc: Namhyung Kim <namhyung@...nel.org>
>>>> Cc: Jiri Olsa <jolsa@...nel.org>
>>>> Signed-off-by: Taeung Song <treeze.taeung@...il.com>
>>>> ---
>>>> tools/perf/builtin-config.c | 1 +
>>>> tools/perf/util/config.c | 123 ++++++++++++++++++++++++++++++++++++++++++++
>>>> tools/perf/util/config.h | 21 ++++++++
>>>> 3 files changed, 145 insertions(+)
>>>> create mode 100644 tools/perf/util/config.h
>>>>
>>>> diff --git a/tools/perf/builtin-config.c b/tools/perf/builtin-config.c
>>>> index c42448e..412c725 100644
>>>> --- a/tools/perf/builtin-config.c
>>>> +++ b/tools/perf/builtin-config.c
>>>> @@ -12,6 +12,7 @@
>>>> #include <subcmd/parse-options.h>
>>>> #include "util/util.h"
>>>> #include "util/debug.h"
>>>> +#include "util/config.h"
>>>>
>>>> static bool use_system_config, use_user_config;
>>>>
>>>> diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
>>>> index 4e72763..b9660e4 100644
>>>> --- a/tools/perf/util/config.c
>>>> +++ b/tools/perf/util/config.c
>>>> @@ -13,6 +13,7 @@
>>>> #include <subcmd/exec-cmd.h>
>>>> #include "util/hist.h" /* perf_hist_config */
>>>> #include "util/llvm-utils.h" /* perf_llvm_config */
>>>> +#include "config.h"
>>>>
>>>> #define MAXNAME (256)
>>>>
>>>> @@ -506,6 +507,128 @@ out:
>>>> return ret;
>>>> }
>>>>
>>>> +static struct perf_config_item *find_config(struct list_head *config_list,
>>>> + const char *section,
>>>> + const char *name)
>>>> +{
>>>> + struct perf_config_item *config;
>>>> +
>>>> + list_for_each_entry(config, config_list, list) {
>>>> + if (!strcmp(config->section, section) &&
>>>> + !strcmp(config->name, name))
>>>> + return config;
>>>> + }
>>>
>>> Hmm.. why do you remove the section list?
>>>
>>
>> IMHO, there are several reasons
>>
>> 1) To use only one list (default config, custom config(user/system))
>>
>> 1-1) I used two list that were 'list_head sections'
>> and 'config_item default_configs[]'. So if checking
>> type of config variable, two for-loop must be needed
>> for each list. Because two structure was different i.e.
>>
>> 'sections' list mean config_section list
>> that each section contain config_element list.
>> (there wasn't telling about correct type of 'value' instead of string(char
>> *))
>>
>> struct config_element {
>> char *name;
>> char *value;
>> struct list_head list;
>> };
>>
>> struct config_section {
>> char *name;
>> struct list_head element_head;
>> struct list_head list;
>> };
>>
>> 'struct config_item default_configs[]' mean all default configs.
>>
>> struct config_item {
>> const char *section;
>> const char *name;
>> union {
>> bool b;
>> int i;
>> u32 l;
>> u64 ll;
>> float f;
>> double d;
>> const char *s;
>> } value;
>> enum config_type type;
>> const char *desc;
>> };
>>
>>
>> IMHO, I think this is a bit complex
>> and I want to simplify the perf's config list on perf-config.
>>
>> 2) A small number of perf's configs
>>
>> I think perf's configs aren't too many so I think
>> two structure for section and element aren't needed.
>
> OK.
>
>
>>
>> 3) A object for a config variable need to have enough info for itself
>>
>> This is a bit similar to 1) reason.
>> If using only 'struct config_item' for the config list,
>> it can contain section name, name, values(default, user config,
>> system config, both config), correct type, etc.
>>
>> If we do, we needn't to find detail for a config variable at other objects
>> e.g.
>> When we find correct type of a config variable,
>> we needn't to do for-loop for default_configs[] in order to know the
>> type.
>
> I'm not sure I understand you correctly, but I think this is not
> related to the two-level structure.
What you said is right.
I just thought using two lists (list_head sections, default_configs[])
was complex..
At this patchset, I only focused on simplifying the config list on
perf-config..
As you said, it hasn't problems to use the two-level structure i.e.
struct config_element
struct config_section (that has multiple elements)
So, what about this structures ?
(you may already think about it, but..)
struct config_element {
char *name;
char *value; /*from the two config file (user/system)*/
union {
bool b;
int i;
u32 l;
u64 ll;
float f;
double d;
const char *s;
} default_value; /* perf's default config value */
enum config_type type;
struct list_head list;
};
struct config_section {
char *name;
struct list_head element_head;
struct list_head list;
};
Because I want to use only one list (default_configs + sections)
for more concise code than old code.
>
>>
>>
>> I think this is better than old two structure.
>>
>>>> +
>>>> + return NULL;
>>>> +}
>>>> +
>>>> +static struct perf_config_item *add_config(struct list_head *config_list,
>>>> + const char *section,
>>>> + const char *name)
>>>> +{
>>>> + struct perf_config_item *config = zalloc(sizeof(*config));
>>>> +
>>>> + if (!config)
>>>> + return NULL;
>>>> +
>>>> + config->section = strdup(section);
>>>> + if (!section)
>>>> + goto out_err;
>>>> +
>>>> + config->name = strdup(name);
>>>> + if (!name) {
>>>> + free((char *)config->section);
>>>> + goto out_err;
>>>> + }
>>>> +
>>>> + list_add_tail(&config->list, config_list);
>>>> + return config;
>>>> +
>>>> +out_err:
>>>> + free(config);
>>>> + pr_err("%s: strdup failed\n", __func__);
>>>> + return NULL;
>>>> +}
>>>> +
>>>> +static int set_value(struct perf_config_item *config, const char *value)
>>>> +{
>>>> + char *val = strdup(value);
>>>> +
>>>> + if (!val)
>>>> + return -1;
>>>> + config->value = val;
>>>
>>> It seems to overwrite old value..
>>>
>>
>> Yes, I know it.
>> If don't using '--user' or '--system',
>> there isn't exclusive config file path
>> then have to read both config files.
>>
>> But because user config file has a high order of priority,
>> if two config file has same variable, old value(for system config)
>> must be overwrote by new value(for user config).
>
> But shouldn't it free the old value before overwriting?
>
Sorry, I missed free() out.
I'll fix it.
Thanks,
Taeung
>
>>
>>>
>>>
>>>> +
>>>> + return 0;
>>>> +}
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