Re: [PATCH v6 2/4] tools/perf: extend format_alias() to include event parameters

[Jiri Olsa <jolsa@redhat.com>]

On Sun, Dec 21, 2014 at 11:49:25PM -0800, Sukadev Bhattiprolu wrote:
> From: Cody P Schafer <cody@linux.vnet.ibm.com>
> 
> This causes `perf list pmu` to show parameters for parameterized events
> like:
> 
>   pmu/event_name,param1=?,param2=?/ [Kernel PMU event]
> 
> An example:
> 
>   hv_24x7/HPM_TLBIE__PHYS_CORE,core=?/ [Kernel PMU event]
> 
> Changelog[v6]
> 	[Jir Olsa, Sukadev Bhattiprolu] Drop the '$' sign and go back to
> 	just printing whatevever sysfs provides (which is '=?') to identify
> 	required parameters. sysfs also now uses parameters like 'core'
> 	and 'vcpu' rather than 'starting_index'.
> 
> Changelog[v5]
> 	[Jiri Olsa, Peter Zijlstra] Use '$' to prefix parameterized events.
> 
> Changelog[v4]
> 	[Jiri Olsa] If the parameter for an event in sysfs is 'param=val',
> 	have perf-list show the event as 'param=?' rather than 'val=?'.
> 
> CC: Haren Myneni <hbabu@us.ibm.com>
> CC: Cody P Schafer <dev@codyps.com>
> Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
> Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
> ---
>  tools/perf/util/pmu.c | 27 ++++++++++++++++++++++++++-
>  1 file changed, 26 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index cb516dd..d208fef 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -810,10 +810,35 @@ void perf_pmu__set_format(unsigned long *bits, long from, long to)
>  		set_bit(b, bits);
>  }
>  
> +static int sub_non_neg(int a, int b)
> +{
> +	if (b > a)
> +		return 0;
> +	return a - b;
> +}
> +
>  static char *format_alias(char *buf, int len, struct perf_pmu *pmu,
>  			  struct perf_pmu_alias *alias)
>  {
> -	snprintf(buf, len, "%s/%s/", pmu->name, alias->name);
> +	struct parse_events_term *term;
> +	int used = snprintf(buf, len, "%s/%s", pmu->name, alias->name);
> +
> +	list_for_each_entry(term, &alias->terms, list)
> +		if (term->type_val == PARSE_EVENTS__TERM_TYPE_STR)
> +			used += snprintf(buf + used, sub_non_neg(len, used),
> +					",%s=%s", term->config,
> +					term->val.str);

why not display PARSE_EVENTS__TERM_TYPE_NUM as well?

jirka