Re: [RFC PATCH v1 02/37] libperf cpumap: improve max function

Em Tue, Aug 31, 2021 at 03:47:10PM -0300, Arnaldo Carvalho de Melo escreveu:

Em Sat, Aug 21, 2021 at 11:19:08AM +0200, Riccardo Mancini escreveu:

quoted

quoted

From commit 7074674e7338863e ("perf cpumap: Maintain cpumaps ordered and

without dups"), perf_cpu_map elements are sorted in ascending order.

This patch improves the perf_cpu_map__max function by returning the last
element.

Signed-off-by: Riccardo Mancini <redacted>
---
 tools/lib/perf/cpumap.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c
index fb633272be3aaed9..80e03b2f0c60cce7 100644
--- a/tools/lib/perf/cpumap.c
+++ b/tools/lib/perf/cpumap.c

@@ -284,14 +284,10 @@ int perf_cpu_map__idx(struct perf_cpu_map *cpus, int cpu)
 
 int perf_cpu_map__max(struct perf_cpu_map *map)
 {
-	int i, max = -1;
-
-	for (i = 0; i < map->nr; i++) {
-		if (map->map[i] > max)
-			max = map->map[i];
-	}
-
-	return max;
+	if (map->nr > 0)
+		return map->map[map->nr-1];
+	else
+		return -1;

Applying, but adding spaces around the '-',

I ended up with this, ok?

+++ b/tools/lib/perf/cpumap.c

@@ -282,10 +282,8 @@ int perf_cpu_map__idx(struct perf_cpu_map *cpus, int cpu)

 int perf_cpu_map__max(struct perf_cpu_map *map)
 {
-       if (map->nr > 0)
-               return map->map[map->nr-1];
-       else
-               return -1;
+       // cpu_map__trim_new() qsort()s it, cpu_map__default_new() sorts it as well.
+       return map->nr > 0 ? map->map[map->nr - 1] : -1;
 }