Re: [PATCH 1/2] perf expr: Add d_ratio operation

From: Jiri Olsa <jolsa@redhat.com>
To: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Andi Kleen <ak@linux.intel.com>,
	Jin Yao <yao.jin@linux.intel.com>,
	John Garry <john.garry@huawei.com>, Paul Clarke <pc@us.ibm.com>,
	Kajol Jain <kjain@linux.ibm.com>,
	linux-kernel@vger.kernel.org,
	Stephane Eranian <eranian@google.com>,
	linux-perf-users@vger.kernel.org
Subject: Re: [PATCH 1/2] perf expr: Add d_ratio operation
Date: Wed, 10 Jun 2020 17:41:29 +0200	[thread overview]
Message-ID: <20200610154129.GA1776102@krava> (raw)
In-Reply-To: <20200610051717.170457-1-irogers@google.com>

On Tue, Jun 09, 2020 at 10:17:15PM -0700, Ian Rogers wrote:
> This simplifies computing ratios in json expressions.

please put in the comment some usage example and add
a test for this to tests/expr.c

same for the '<>' operators in the other patch

I'll put documentation on this together with the rest to
stat man page with my other changes, so no need to document
this, but at least bit more details in changelog ;-)

thanks,
jirka

> 
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>  tools/perf/util/expr.l |  1 +
>  tools/perf/util/expr.y | 14 ++++++++++++--
>  2 files changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/util/expr.l b/tools/perf/util/expr.l
> index f397bf8b1a48..298d86660a96 100644
> --- a/tools/perf/util/expr.l
> +++ b/tools/perf/util/expr.l
> @@ -100,6 +100,7 @@ symbol		({spec}|{sym})+
>  		}
>  	}
>  
> +d_ratio		{ return D_RATIO; }
>  max		{ return MAX; }
>  min		{ return MIN; }
>  if		{ return IF; }
> diff --git a/tools/perf/util/expr.y b/tools/perf/util/expr.y
> index bf3e898e3055..fe145344bb39 100644
> --- a/tools/perf/util/expr.y
> +++ b/tools/perf/util/expr.y
> @@ -10,6 +10,14 @@
>  #include "smt.h"
>  #include <string.h>
>  
> +static double d_ratio(double val0, double val1)
> +{
> +	if (val1 == 0) {
> +		return 0;
> +	}
> +	return  val0 / val1;
> +}
> +
>  %}
>  
>  %define api.pure full
> @@ -28,7 +36,7 @@
>  %token <num> NUMBER
>  %token <str> ID
>  %destructor { free ($$); } <str>
> -%token MIN MAX IF ELSE SMT_ON
> +%token MIN MAX IF ELSE SMT_ON D_RATIO
>  %left MIN MAX IF
>  %left '|'
>  %left '^'
> @@ -64,7 +72,8 @@ other: ID
>  }
>  |
>  MIN | MAX | IF | ELSE | SMT_ON | NUMBER | '|' | '^' | '&' | '-' | '+' | '*' | '/' | '%' | '(' | ')' | ','
> -
> +|
> +D_RATIO
>  
>  all_expr: if_expr			{ *final_val = $1; }
>  	;
> @@ -105,6 +114,7 @@ expr:	  NUMBER
>  	| MIN '(' expr ',' expr ')' { $$ = $3 < $5 ? $3 : $5; }
>  	| MAX '(' expr ',' expr ')' { $$ = $3 > $5 ? $3 : $5; }
>  	| SMT_ON		 { $$ = smt_on() > 0; }
> +	| D_RATIO '(' expr ',' expr ')' { $$ = d_ratio($3,$5); }
>  	;
>  
>  %%
> -- 
> 2.27.0.278.ge193c7cf3a9-goog
>