perf env: Introduce read_cpu_topology_map() method

Out of the code to write the cpu topology map in the perf.data file
header.

Now if one needs the CPU topology map for the running machine, one needs
to call perf_env__read_cpu_topology_map(perf_env) and the info will be
stored in perf_env.cpu.

For now we're using a global perf_env variable, that will have its
contents freed after we run a builtin.

v2: Check perf_env__read_cpu_topology_map() return in
write_cpu_topology() (Kan Liang)

Cc: Adrian Hunter <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Frederic Weisbecker <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Stephane Eranian <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/perf.c

···
  */
 #include "builtin.h"
 
+#include "util/env.h"
 #include "util/exec_cmd.h"
 #include "util/cache.h"
 #include "util/quote.h"
···
 
 	status = p->fn(argc, argv, prefix);
 	exit_browser(status);
+	perf_env__exit(&perf_env);
 
 	if (status)
 		return status & 0xff;

tools/perf/util/env.c

···
+#include "cpumap.h"
 #include "env.h"
 #include "util.h"
 
···
 	zfree(&env->cmdline_argv);
 out_enomem:
 	return -ENOMEM;
+}
+
+int perf_env__read_cpu_topology_map(struct perf_env *env)
+{
+	int cpu, nr_cpus;
+
+	if (env->cpu != NULL)
+		return 0;
+
+	if (env->nr_cpus_avail == 0)
+		env->nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
+
+	nr_cpus = env->nr_cpus_avail;
+	if (nr_cpus == -1)
+		return -EINVAL;
+
+	env->cpu = calloc(nr_cpus, sizeof(env->cpu[0]));
+	if (env->cpu == NULL)
+		return -ENOMEM;
+
+	for (cpu = 0; cpu < nr_cpus; ++cpu) {
+		env->cpu[cpu].core_id	= cpu_map__get_core_id(cpu);
+		env->cpu[cpu].socket_id	= cpu_map__get_socket_id(cpu);
+	}
+
+	env->nr_cpus_avail = nr_cpus;
+	return 0;
 }

tools/perf/util/env.h

···
 
 int perf_env__set_cmdline(struct perf_env *env, int argc, const char *argv[]);
 
+int perf_env__read_cpu_topology_map(struct perf_env *env);
+
 #endif /* __PERF_ENV_H */

tools/perf/util/header.c

···
 	u32 thread_sib;
 	char **core_siblings;
 	char **thread_siblings;
-	int *core_id;
-	int *phy_pkg_id;
 };
 
 static int build_cpu_topo(struct cpu_topo *tp, int cpu)
···
 	}
 	ret = 0;
 done:
-	tp->core_id[cpu] = cpu_map__get_core_id(cpu);
-	tp->phy_pkg_id[cpu] = cpu_map__get_socket_id(cpu);
-
 	if(fp)
 		fclose(fp);
 	free(buf);
···
 	struct cpu_topo *tp;
 	void *addr;
 	u32 nr, i;
-	size_t sz, sz_id;
+	size_t sz;
 	long ncpus;
 	int ret = -1;
 
···
 	nr = (u32)(ncpus & UINT_MAX);
 
 	sz = nr * sizeof(char *);
-	sz_id = nr * sizeof(int);
 
-	addr = calloc(1, sizeof(*tp) + 2 * sz + 2 * sz_id);
+	addr = calloc(1, sizeof(*tp) + 2 * sz);
 	if (!addr)
 		return NULL;
 
···
 	tp->core_siblings = addr;
 	addr += sz;
 	tp->thread_siblings = addr;
-	addr += sz;
-	tp->core_id = addr;
-	addr += sz_id;
-	tp->phy_pkg_id = addr;
 
 	for (i = 0; i < nr; i++) {
 		ret = build_cpu_topo(tp, i);
···
 {
 	struct cpu_topo *tp;
 	u32 i;
-	int ret;
+	int ret, j;
 
 	tp = build_cpu_topology();
 	if (!tp)
···
 			break;
 	}
 
-	for (i = 0; i < tp->cpu_nr; i++) {
-		ret = do_write(fd, &tp->core_id[i], sizeof(int));
+	ret = perf_env__read_cpu_topology_map(&perf_env);
+	if (ret < 0)
+		goto done;
+
+	for (j = 0; j < perf_env.nr_cpus_avail; j++) {
+		ret = do_write(fd, &perf_env.cpu[j].core_id,
+			       sizeof(perf_env.cpu[j].core_id));
 		if (ret < 0)
 			return ret;
-		ret = do_write(fd, &tp->phy_pkg_id[i], sizeof(int));
+		ret = do_write(fd, &perf_env.cpu[j].socket_id,
+			       sizeof(perf_env.cpu[j].socket_id));
 		if (ret < 0)
 			return ret;
 	}