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>
This commit is contained in:
Don Zickus 2014-04-07 14:55:21 -04:00 committed by Jiri Olsa
parent 7c2f8164e5
commit 7780c25bae
2 changed files with 195 additions and 0 deletions

View file

@ -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;
}

View file

@ -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 */