Re: [PATCH 2/4] perf tools: Add functions which can get or set perf config variables.

[taeung]

Hi, Jiri Olsa

Thanks for your feedbacks on my patches.

There are one thing I don't understand very well.
I wrote a number 1) in the middle of the your feedbacks to mark it.

I don't follow, could you elaborate it little more?


On 05/05/2015 04:16 AM, Jiri Olsa wrote:
> On Mon, Apr 27, 2015 at 03:34:24PM +0900, Taeung Song wrote:
> > This patch consists of functions
> > which can get, set specific config variables.
> > For the syntax examples,
> >
> >     perf config [options] [section.subkey[=value] ...]
> >
> >     display key-value pairs of specific config variables
> >     # perf config report.queue-size report.children
> [jolsa@krava perf]$ ./perf config krava.krava
> krava.krava=true
>
> ?
>
> some comments below
>
> >     set specific config variables
> >     # perf config report.queue-size=100M report.children=true
> >
> > Signed-off-by: Taeung Song <treeze.taeung@xxxxxxxxx>
> > ---
> >   tools/perf/Documentation/perf-config.txt |   2 +
> >   tools/perf/builtin-config.c              | 276 ++++++++++++++++++++++++++++++-
> >   tools/perf/util/cache.h                  |  17 ++
> >   tools/perf/util/config.c                 |  30 +++-
> >   4 files changed, 320 insertions(+), 5 deletions(-)
> SNIP
>
> > +static int set_spec_config(const char *section_name, const char *subkey,
> > +			   const char *value)
> >   {
> >   	int ret = 0;
> > +	ret += set_config(section_name, subkey, value);
> > +	ret += perf_configset_write_in_full();
> > +
> > +	return ret;
> > +}
> > +
> > +static void parse_key(const char *var, const char **section_name, const char **subkey)
> > +{
> > +	char *key = strdup(var);
> > +
> > +	if (!key)
> > +		die("%s: strdup failed\n", __func__);
> > +
> > +	*section_name = strsep(&key, ".");
> > +	*subkey = strsep(&key, ".");
> should this check the config syntax? could be used for command line check as well
> > +}
> > +
> > +static int collect_config(const char *var, const char *value,
> > +			  void *cb __maybe_unused)
> > +{
> > +	struct config_section *section_node;
> > +	const char *section_name, *subkey;
> SNIP
>
> > +	}
> > +	for (i = 0; key[i]; i++) {
> > +		if (i == 0 && !isalpha(key[i++]))
> > +			goto out_err;
> > +
> > +		switch (key[i]) {
> > +		case '.':
> > +			num_dot += 1;
> > +			if (!isalpha(key[++i]))
> > +				goto out_err;
> > +			break;
> > +		case '=':
> > +			num_equals += 1;
> > +			break;
> > +		default:
> > +			if (!isalpha(key[i]) && !isalnum(key[i]))
> > +				goto out_err;
> you dont allow '-' in the key report.queue-size, I think we should support also _
>
> also please put the name checks into separated function
>
> > +		}
> > +	}
> > +
> > +	if (num_equals > 1 || num_dot > 1)
> > +		goto out_err;
> > +
> > +	given_value = strchr(key, '=');
> > +	if (given_value == NULL || given_value == key)
> > +		given_value = NULL;
> SNIP
>
> >   	argc = parse_options(argc, argv, config_options, config_usage,
> >   			     PARSE_OPT_STOP_AT_NON_OPTION);
> > +	if (origin_argc > argc)
> > +		is_option = true;
> > +	else
> > +		is_option = false;
> > +
> > +	if (!is_option && argc >= 0) {
> > +		switch (argc) {
> > +		case 0:
> > +			break;
> > +		default:
> > +			for (i = 0; argv[i]; i++) {
> > +				value = strrchr(argv[i], '=');
> > +				if (value == NULL || value == argv[i])
> hum, so you let go in args like '=krava' ?
>
> why dont you completely check the name (assignment string) first
> and decide later about the callback
1) I understood that the name must be completely checked first.
   But I don't know the callback. What does it mean ?
   Could you elaborate it little more?

Thanks,
Taeung

> > +					ret = perf_configset_with_option(show_spec_config, argv[i]);
> > +				else
> > +					ret = perf_configset_with_option(set_spec_config, argv[i]);
> > +				if (ret < 0)
> > +					break;
> > +			}
> > +			goto out;
> > +		}
> > +	}
> SNIP
>
> > @@ -502,6 +501,31 @@ out:
> >   	return ret;
> >   }
> >   
> > +int perf_configset_write_in_full(void)
> > +{
> > +	struct config_section *section_node;
> > +	struct config_element *element_node;
> > +	const char *first_line = "# this file is auto-generated.";
> so you parse whole config, change it and write back..
> hum, I dont see better way.. and I like the first line ;-)
>
> > +	FILE *fp = fopen(config_file_name, "w");
> > +
> > +	if (!fp)
> > +		return -1;
> > +
> > +	fprintf(fp, "%s\n", first_line);
> > +	/* overwrite configvariables */
> > +	list_for_each_entry(section_node, sections, list) {
> > +		fprintf(fp, "[%s]\n", section_node->name);
> > +		list_for_each_entry(element_node, &section_node->element_head, list) {
> > +			if (element_node->value)
> > +				fprintf(fp, "\t%s = %s\n",
> > +					element_node->subkey, element_node->value);
> > +		}
> > +	}
> > +	fclose(fp);
> > +
> > +	return 0;
> > +}
> > +
> >   /*
> >    * Call this to report error for your variable that should not
> >    * get a boolean value (i.e. "[my] var" means "true").
> > --
> > 1.9.1

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