birq/cpu_parse.c

/* cpu_parse.c
 * Parse CPU-related files.
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <dirent.h>
#include <limits.h>
#include <ctype.h>
#include <unistd.h>

#include "lub/list.h"
#include "cpumask.h"
#include "cpu.h"
#include "irq.h"

int cpu_list_compare(const void *first, const void *second)
{
	const cpu_t *f = (const cpu_t *)first;
	const cpu_t *s = (const cpu_t *)second;
	return (f->id - s->id);
}

int cpu_list_compare_len(const void *first, const void *second)
{
	const cpu_t *f = (const cpu_t *)first;
	const cpu_t *s = (const cpu_t *)second;
	return (lub_list_len(f->irqs) - lub_list_len(s->irqs));
}

static cpu_t * cpu_new(unsigned int id)
{
	cpu_t *new;

	if (!(new = malloc(sizeof(*new))))
		return NULL;
	new->id = id;
	new->old_load_all = 0;
	new->old_load_irq = 0;
	new->load = 0;
	new->irqs = lub_list_new(irq_list_compare);
	cpus_clear(new->cpumask);
	cpu_set(new->id, new->cpumask);

	return new;
}

static void cpu_free(cpu_t *cpu)
{
	lub_list_node_t *node;

	while ((node = lub_list__get_tail(cpu->irqs))) {
		lub_list_del(cpu->irqs, node);
		lub_list_node_free(node);
	}
	lub_list_free(cpu->irqs);
	free(cpu);
}

/* Search for CPU with specified package and core IDs.
   The second CPU with the same IDs is a thread of Hyper Threading.
   We don't want to use HT for IRQ balancing. */
static cpu_t * cpu_list_search_ht(lub_list_t *cpus,
	unsigned int package_id,
	unsigned int core_id)
{
	lub_list_node_t *iter;

	for (iter = lub_list_iterator_init(cpus); iter;
		iter = lub_list_iterator_next(iter)) {
		cpu_t *cpu;
		cpu = (cpu_t *)lub_list_node__get_data(iter);
		if (cpu->package_id != package_id)
			continue;
		if (cpu->core_id != core_id)
			continue;
		return cpu;
	}

	return NULL;
}

cpu_t * cpu_list_search(lub_list_t *cpus, unsigned int id)
{
	lub_list_node_t *node;
	cpu_t search;

	search.id = id;
	node = lub_list_search(cpus, &search);
	if (!node)
		return NULL;
	return (cpu_t *)lub_list_node__get_data(node);
}

static cpu_t * cpu_list_add(lub_list_t *cpus, cpu_t *cpu)
{
	cpu_t *old = cpu_list_search(cpus, cpu->id);

	if (old) /* CPU already exists. May be renew some fields later */
		return old;
	lub_list_add(cpus, cpu);

	return cpu;
}

int cpu_list_free(lub_list_t *cpus)
{
	lub_list_node_t *iter;
	while ((iter = lub_list__get_head(cpus))) {
		cpu_t *cpu;
		cpu = (cpu_t *)lub_list_node__get_data(iter);
		cpu_free(cpu);
		lub_list_del(cpus, iter);
		lub_list_node_free(iter);
	}
	lub_list_free(cpus);
	return 0;
}

/* Show CPU information */
static void show_cpu_info(cpu_t *cpu)
{
	char buf[NR_CPUS + 1];
	cpumask_scnprintf(buf, sizeof(buf), cpu->cpumask);
	printf("CPU %d package %d core %d mask %s\n", cpu->id, cpu->package_id, cpu->core_id, buf);
}

/* Show CPU list */
int show_cpus(lub_list_t *cpus)
{
	lub_list_node_t *iter;
	for (iter = lub_list_iterator_init(cpus); iter;
		iter = lub_list_iterator_next(iter)) {
		cpu_t *cpu;
		cpu = (cpu_t *)lub_list_node__get_data(iter);
		show_cpu_info(cpu);
	}
	return 0;
}

/* Search for CPUs */
int scan_cpus(lub_list_t *cpus)
{
	FILE *fd;
	char path[PATH_MAX];
	unsigned int id;
	unsigned int package_id;
	unsigned int core_id;
	cpu_t *new;

	for (id = 0; id < NR_CPUS; id++) {
		sprintf(path, "%s/cpu%d", SYSFS_CPU_PATH, id);
		if (access(path, F_OK))
			break;

		/* Try to get package_id */
		sprintf(path, "%s/cpu%d/topology/physical_package_id",
			SYSFS_CPU_PATH, id);
		if (!(fd = fopen(path, "r")))
			continue;
		if (fscanf(fd, "%u", &package_id) < 0) {
			fclose(fd);
			continue;
		}
		fclose(fd);

		/* Try to get core_id */
		sprintf(path, "%s/cpu%d/topology/core_id",
			SYSFS_CPU_PATH, id);
		if (!(fd = fopen(path, "r")))
			continue;
		if (fscanf(fd, "%u", &core_id) < 0) {
			fclose(fd);
			continue;
		}
		fclose(fd);

		/* Don't use second thread of Hyper Threading */
		if (cpu_list_search_ht(cpus, package_id, core_id))
			continue;

		new = cpu_new(id);
		new->package_id = package_id;
		new->core_id = core_id;
		cpu_list_add(cpus, new);
	}

	return 0;
}