[tip:perf/core] perf cpumap: Introduce cpu_map__snprint_mask()

[tip-bot for Namhyung Kim]

Commit-ID:  4400ac8a9a900318f8516dc0fb94075cb3fdb50d
Gitweb:     http://git.kernel.org/tip/4400ac8a9a900318f8516dc0fb94075cb3fdb50d
Author:     Namhyung Kim <namhy...@kernel.org>
AuthorDate: Fri, 24 Feb 2017 10:12:49 +0900
Committer:  Arnaldo Carvalho de Melo <a...@redhat.com>
CommitDate: Fri, 3 Mar 2017 19:07:17 -0300

perf cpumap: Introduce cpu_map__snprint_mask()

The cpu_map__snprint_mask() generates a string representation of a
cpumask bitmap.  For cpu 0 to 11, it'll return "fff".

Committer notes:

Fix compiler warning on some toolchains:

    19 fedora:24-x-ARC-uClibc: FAIL

    CC       /tmp/build/perf/util/cpumap.o
  util/cpumap.c: In function 'hex_char':
  util/cpumap.c:679:2: error: comparison is always true due to limited range of 
data type [-Werror=type-limits]
    if (0 <= val && val <= 9)
    ^
  cc1: all warnings being treated as errors

Applying patch from Namhyung that makes function receive an 'unsigned
char', that is what the callers are passing to this function.

Signed-off-by: Namhyung Kim <namhy...@kernel.org>
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: Jiri Olsa <jo...@kernel.org>
Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: kernel-t...@lge.com
Link: http://lkml.kernel.org/r/20170224011251.14946-2-namhy...@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com>
---
 tools/perf/util/cpumap.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/cpumap.h |  1 +
 2 files changed, 47 insertions(+)

diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
index 39ad2ca..061018b 100644
--- a/tools/perf/util/cpumap.c
+++ b/tools/perf/util/cpumap.c
@@ -673,3 +673,49 @@ size_t cpu_map__snprint(struct cpu_map *map, char *buf, 
size_t size)
        pr_debug("cpumask list: %s\n", buf);
        return ret;
 }
+
+static char hex_char(unsigned char val)
+{
+       if (val < 10)
+               return val + '0';
+       if (val < 16)
+               return val - 10 + 'a';
+       return '?';
+}
+
+size_t cpu_map__snprint_mask(struct cpu_map *map, char *buf, size_t size)
+{
+       int i, cpu;
+       char *ptr = buf;
+       unsigned char *bitmap;
+       int last_cpu = cpu_map__cpu(map, map->nr - 1);
+
+       bitmap = zalloc((last_cpu + 7) / 8);
+       if (bitmap == NULL) {
+               buf[0] = '\0';
+               return 0;
+       }
+
+       for (i = 0; i < map->nr; i++) {
+               cpu = cpu_map__cpu(map, i);
+               bitmap[cpu / 8] |= 1 << (cpu % 8);
+       }
+
+       for (cpu = last_cpu / 4 * 4; cpu >= 0; cpu -= 4) {
+               unsigned char bits = bitmap[cpu / 8];
+
+               if (cpu % 8)
+                       bits >>= 4;
+               else
+                       bits &= 0xf;
+
+               *ptr++ = hex_char(bits);
+               if ((cpu % 32) == 0 && cpu > 0)
+                       *ptr++ = ',';
+       }
+       *ptr = '\0';
+       free(bitmap);
+
+       buf[size - 1] = '\0';
+       return ptr - buf;
+}
diff --git a/tools/perf/util/cpumap.h b/tools/perf/util/cpumap.h
index e844916..6b8bff8 100644
--- a/tools/perf/util/cpumap.h
+++ b/tools/perf/util/cpumap.h
@@ -20,6 +20,7 @@ struct cpu_map *cpu_map__dummy_new(void);
 struct cpu_map *cpu_map__new_data(struct cpu_map_data *data);
 struct cpu_map *cpu_map__read(FILE *file);
 size_t cpu_map__snprint(struct cpu_map *map, char *buf, size_t size);
+size_t cpu_map__snprint_mask(struct cpu_map *map, char *buf, size_t size);
 size_t cpu_map__fprintf(struct cpu_map *map, FILE *fp);
 int cpu_map__get_socket_id(int cpu);
 int cpu_map__get_socket(struct cpu_map *map, int idx, void *data);