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Commit 7780c25b authored by Don Zickus's avatar Don Zickus Committed by Jiri Olsa
Browse files

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: default avatarDon Zickus <dzickus@redhat.com>
Reviewed-by: default avatarNamhyung 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: default avatarJiri Olsa <jolsa@redhat.com>
parent 7c2f8164

tools/perf/util/cpumap.c

+160 −0
Original line number Diff line number Diff line
@@ -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;

}

tools/perf/util/cpumap.h

+35 −0
Original line number Diff line number Diff line
@@ -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 */