perf tools: Allow ability to map cpus to nodes easily

This patch figures out the max number of cpus and nodes that are on the
system and creates a map of cpu to node.  This allows us to provide a cpu
and quickly get the node associated with it.

It was mostly copied from builtin-kmem.c and tweaked slightly to use less memory
(use possible cpus instead of max).  It also calculates the max number of nodes.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1396896924-129847-2-git-send-email-dzickus@redhat.com
[ Removing out label code in init_cpunode_map ]
[ Adding check for snprintf error ]
[ Removing unneeded returns ]
Signed-off-by: Jiri Olsa <jolsa@redhat.com>

diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
index 7fe4994..526da02 100644 (file)
--- a/tools/perf/util/cpumap.c
+++ b/tools/perf/util/cpumap.c
@@ -317,3 +317,163 @@ int cpu_map__build_core_map(struct cpu_map *cpus, struct cpu_map **corep)
 {
        return cpu_map__build_map(cpus, corep, cpu_map__get_core);
 }
+
+/* setup simple routines to easily access node numbers given a cpu number */
+static int get_max_num(char *path, int *max)
+{
+       size_t num;
+       char *buf;
+       int err = 0;
+
+       if (filename__read_str(path, &buf, &num))
+               return -1;
+
+       buf[num] = '\0';
+
+       /* start on the right, to find highest node num */
+       while (--num) {
+               if ((buf[num] == ',') || (buf[num] == '-')) {
+                       num++;
+                       break;
+               }
+       }
+       if (sscanf(&buf[num], "%d", max) < 1) {
+               err = -1;
+               goto out;
+       }
+
+       /* convert from 0-based to 1-based */
+       (*max)++;
+
+out:
+       free(buf);
+       return err;
+}
+
+/* Determine highest possible cpu in the system for sparse allocation */
+static void set_max_cpu_num(void)
+{
+       const char *mnt;
+       char path[PATH_MAX];
+       int ret = -1;
+
+       /* set up default */
+       max_cpu_num = 4096;
+
+       mnt = sysfs__mountpoint();
+       if (!mnt)
+               goto out;
+
+       /* get the highest possible cpu number for a sparse allocation */
+       ret = snprintf(path, PATH_MAX, "%s/devices/system/cpu/kernel_max", mnt);
+       if (ret == PATH_MAX) {
+               pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX);
+               goto out;
+       }
+
+       ret = get_max_num(path, &max_cpu_num);
+
+out:
+       if (ret)
+               pr_err("Failed to read max cpus, using default of %d\n", max_cpu_num);
+}
+
+/* Determine highest possible node in the system for sparse allocation */
+static void set_max_node_num(void)
+{
+       const char *mnt;
+       char path[PATH_MAX];
+       int ret = -1;
+
+       /* set up default */
+       max_node_num = 8;
+
+       mnt = sysfs__mountpoint();
+       if (!mnt)
+               goto out;
+
+       /* get the highest possible cpu number for a sparse allocation */
+       ret = snprintf(path, PATH_MAX, "%s/devices/system/node/possible", mnt);
+       if (ret == PATH_MAX) {
+               pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX);
+               goto out;
+       }
+
+       ret = get_max_num(path, &max_node_num);
+
+out:
+       if (ret)
+               pr_err("Failed to read max nodes, using default of %d\n", max_node_num);
+}
+
+static int init_cpunode_map(void)
+{
+       int i;
+
+       set_max_cpu_num();
+       set_max_node_num();
+
+       cpunode_map = calloc(max_cpu_num, sizeof(int));
+       if (!cpunode_map) {
+               pr_err("%s: calloc failed\n", __func__);
+               return -1;
+       }
+
+       for (i = 0; i < max_cpu_num; i++)
+               cpunode_map[i] = -1;
+
+       return 0;
+}
+
+int cpu__setup_cpunode_map(void)
+{
+       struct dirent *dent1, *dent2;
+       DIR *dir1, *dir2;
+       unsigned int cpu, mem;
+       char buf[PATH_MAX];
+       char path[PATH_MAX];
+       const char *mnt;
+       int n;
+
+       /* initialize globals */
+       if (init_cpunode_map())
+               return -1;
+
+       mnt = sysfs__mountpoint();
+       if (!mnt)
+               return 0;
+
+       n = snprintf(path, PATH_MAX, "%s/devices/system/node", mnt);
+       if (n == PATH_MAX) {
+               pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX);
+               return -1;
+       }
+
+       dir1 = opendir(path);
+       if (!dir1)
+               return 0;
+
+       /* walk tree and setup map */
+       while ((dent1 = readdir(dir1)) != NULL) {
+               if (dent1->d_type != DT_DIR || sscanf(dent1->d_name, "node%u", &mem) < 1)
+                       continue;
+
+               n = snprintf(buf, PATH_MAX, "%s/%s", path, dent1->d_name);
+               if (n == PATH_MAX) {
+                       pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX);
+                       continue;
+               }
+
+               dir2 = opendir(buf);
+               if (!dir2)
+                       continue;
+               while ((dent2 = readdir(dir2)) != NULL) {
+                       if (dent2->d_type != DT_LNK || sscanf(dent2->d_name, "cpu%u", &cpu) < 1)
+                               continue;
+                       cpunode_map[cpu] = mem;
+               }
+               closedir(dir2);
+       }
+       closedir(dir1);
+       return 0;
+}

diff --git a/tools/perf/util/cpumap.h b/tools/perf/util/cpumap.h
index b123bb9..61a6548 100644 (file)
--- a/tools/perf/util/cpumap.h
+++ b/tools/perf/util/cpumap.h
@@ -4,6 +4,9 @@
 #include <stdio.h>
 #include <stdbool.h>
 
+#include "perf.h"
+#include "util/debug.h"
+
 struct cpu_map {
        int nr;
        int map[];
@@ -46,4 +49,36 @@ static inline bool cpu_map__empty(const struct cpu_map *map)
        return map ? map->map[0] == -1 : true;
 }
 
+int max_cpu_num;
+int max_node_num;
+int *cpunode_map;
+
+int cpu__setup_cpunode_map(void);
+
+static inline int cpu__max_node(void)
+{
+       if (unlikely(!max_node_num))
+               pr_debug("cpu_map not initialized\n");
+
+       return max_node_num;
+}
+
+static inline int cpu__max_cpu(void)
+{
+       if (unlikely(!max_cpu_num))
+               pr_debug("cpu_map not initialized\n");
+
+       return max_cpu_num;
+}
+
+static inline int cpu__get_node(int cpu)
+{
+       if (unlikely(cpunode_map == NULL)) {
+               pr_debug("cpu_map not initialized\n");
+               return -1;
+       }
+
+       return cpunode_map[cpu];
+}
+
 #endif /* __PERF_CPUMAP_H */