perf stat: Fix --no-scale

The -c option to enable multiplex scaling has been useless for quite
some time because scaling is default.

It's only useful as --no-scale to disable scaling. But the non scaling
code path has bitrotted and doesn't print anything because perf output
code relies on value run/ena information.

Also even when we don't want to scale a value it's still useful to show
its multiplex percentage.

This patch:
  - Fixes help and documentation to show --no-scale instead of -c
  - Removes -c, only keeps the long option because -c doesn't support negatives.
  - Enables running/enabled even with --no-scale
  - And fixes some other problems in the no-scale output.

Before:

  $ perf stat --no-scale -e cycles true

   Performance counter stats for 'true':

       <not counted>      cycles

         0.000984154 seconds time elapsed

After:

  $ ./perf stat --no-scale -e cycles true

   Performance counter stats for 'true':

             706,070      cycles

         0.001219821 seconds time elapsed

Signed-off-by: Andi Kleen <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
LPU-Reference: [email protected]
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: Andi Kleen

tools/perf/Documentation/perf-stat.txt

@@ -72,9 +72,8 @@ report::
 --all-cpus::
         system-wide collection from all CPUs (default if no target is specified)
 
--c::
---scale::
-	scale/normalize counter values
+--no-scale::
+	Don't scale/normalize counter values
 
 -d::
 --detailed::

tools/perf/builtin-stat.c

@@ -718,7 +718,8 @@ static struct option stat_options[] = {
 		    "system-wide collection from all CPUs"),
 	OPT_BOOLEAN('g', "group", &group,
 		    "put the counters into a counter group"),
-	OPT_BOOLEAN('c', "scale", &stat_config.scale, "scale/normalize counters"),
+	OPT_BOOLEAN(0, "scale", &stat_config.scale,
+		    "Use --no-scale to disable counter scaling for multiplexing"),
 	OPT_INCR('v', "verbose", &verbose,
 		    "be more verbose (show counter open errors, etc)"),
 	OPT_INTEGER('r', "repeat", &stat_config.run_count,

tools/perf/util/evsel.c

@@ -1344,8 +1344,7 @@ void perf_counts_values__scale(struct perf_counts_values *count,
 			scaled = 1;
 			count->val = (u64)((double) count->val * count->ena / count->run + 0.5);
 		}
-	} else
-		count->ena = count->run = 0;
+	}
 
 	if (pscaled)
 		*pscaled = scaled;

tools/perf/util/stat.c

@@ -291,10 +291,8 @@ process_counter_values(struct perf_stat_config *config, struct perf_evsel *evsel
 		break;
 	case AGGR_GLOBAL:
 		aggr->val += count->val;
-		if (config->scale) {
-			aggr->ena += count->ena;
-			aggr->run += count->run;
-		}
+		aggr->ena += count->ena;
+		aggr->run += count->run;
 	case AGGR_UNSET:
 	default:
 		break;
@@ -442,10 +440,8 @@ int create_perf_stat_counter(struct perf_evsel *evsel,
 	struct perf_event_attr *attr = &evsel->attr;
 	struct perf_evsel *leader = evsel->leader;
 
-	if (config->scale) {
-		attr->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED |
-				    PERF_FORMAT_TOTAL_TIME_RUNNING;
-	}
+	attr->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED |
+			    PERF_FORMAT_TOTAL_TIME_RUNNING;
 
 	/*
 	 * The event is part of non trivial group, let's enable