Re: [PATCH 11/19] perf metric: Compute referenced metrics

[kajoljain <kjain@linux.ibm.com>]

On 7/19/20 11:43 PM, Jiri Olsa wrote:
> Adding computation (expr__parse call) of referenced metric at
> the point when it needs to be resolved during the parent metric
> computation.
> 
> Once the inner metric is computed, the result is stored and
> used if there's another usage of that metric.
> 
> Acked-by: Ian Rogers <irogers@google.com>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>

Reviewed-By : Kajol Jain<kjain@linux.ibm.com>

Thanks,
Kajol Jain
> ---
>  tools/perf/util/expr.c | 31 +++++++++++++++++++++++++++++++
>  tools/perf/util/expr.h |  3 +++
>  tools/perf/util/expr.y |  4 ++--
>  3 files changed, 36 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/util/expr.c b/tools/perf/util/expr.c
> index d3997c2b4a90..a346ca590513 100644
> --- a/tools/perf/util/expr.c
> +++ b/tools/perf/util/expr.c
> @@ -112,6 +112,7 @@ int expr__add_ref(struct expr_parse_ctx *ctx, struct metric_ref *ref)
>  	 */
>  	data_ptr->ref.metric_name = ref->metric_name;
>  	data_ptr->ref.metric_expr = ref->metric_expr;
> +	data_ptr->ref.counted = false;
>  	data_ptr->is_ref = true;
>  
>  	ret = hashmap__set(&ctx->ids, name, data_ptr,
> @@ -133,6 +134,34 @@ int expr__get_id(struct expr_parse_ctx *ctx, const char *id,
>  	return hashmap__find(&ctx->ids, id, (void **)data) ? 0 : -1;
>  }
>  
> +int expr__resolve_id(struct expr_parse_ctx *ctx, const char *id,
> +		     struct expr_id_data **datap)
> +{
> +	struct expr_id_data *data;
> +
> +	if (expr__get_id(ctx, id, datap) || !*datap) {
> +		pr_debug("%s not found\n", id);
> +		return -1;
> +	}
> +
> +	data = *datap;
> +
> +	pr_debug2("lookup: is_ref %d, counted %d, val %f: %s\n",
> +		  data->is_ref, data->ref.counted, data->val, id);
> +
> +	if (data->is_ref && !data->ref.counted) {
> +		data->ref.counted = true;
> +		pr_debug("processing metric: %s ENTRY\n", id);
> +		if (expr__parse(&data->val, ctx, data->ref.metric_expr, 1)) {
> +			pr_debug("%s failed to count\n", id);
> +			return -1;
> +		}
> +		pr_debug("processing metric: %s EXIT: %f\n", id, data->val);
> +	}
> +
> +	return 0;
> +}
> +
>  void expr__del_id(struct expr_parse_ctx *ctx, const char *id)
>  {
>  	struct expr_id_data *old_val = NULL;
> @@ -173,6 +202,8 @@ __expr__parse(double *val, struct expr_parse_ctx *ctx, const char *expr,
>  	void *scanner;
>  	int ret;
>  
> +	pr_debug2("parsing metric: %s\n", expr);
> +
>  	ret = expr_lex_init_extra(&scanner_ctx, &scanner);
>  	if (ret)
>  		return ret;
> diff --git a/tools/perf/util/expr.h b/tools/perf/util/expr.h
> index 81d04ff7f857..9ed208d93418 100644
> --- a/tools/perf/util/expr.h
> +++ b/tools/perf/util/expr.h
> @@ -23,6 +23,7 @@ struct expr_id_data {
>  		struct {
>  			const char *metric_name;
>  			const char *metric_expr;
> +			bool counted;
>  		} ref;
>  	};
>  
> @@ -42,6 +43,8 @@ int expr__add_id_val(struct expr_parse_ctx *ctx, const char *id, double val);
>  int expr__add_ref(struct expr_parse_ctx *ctx, struct metric_ref *ref);
>  int expr__get_id(struct expr_parse_ctx *ctx, const char *id,
>  		 struct expr_id_data **data);
> +int expr__resolve_id(struct expr_parse_ctx *ctx, const char *id,
> +		     struct expr_id_data **datap);
>  int expr__parse(double *final_val, struct expr_parse_ctx *ctx,
>  		const char *expr, int runtime);
>  int expr__find_other(const char *expr, const char *one,
> diff --git a/tools/perf/util/expr.y b/tools/perf/util/expr.y
> index 0d4f5d324be7..d34b370391c6 100644
> --- a/tools/perf/util/expr.y
> +++ b/tools/perf/util/expr.y
> @@ -88,11 +88,11 @@ expr:	  NUMBER
>  	| ID			{
>  					struct expr_id_data *data;
>  
> -					if (expr__get_id(ctx, $1, &data) || !data) {
> -						pr_debug("%s not found\n", $1);
> +					if (expr__resolve_id(ctx, $1, &data)) {
>  						free($1);
>  						YYABORT;
>  					}
> +
>  					$$ = data->val;
>  					free($1);
>  				}
>