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
--- a/tools/perf/util/cpumap.c
+++ b/tools/perf/util/cpumap.c
@@ -317,3 +317,163 @@
{
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;
+}