1 files changed, 59 insertions, 0 deletions
diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
new file mode 100644
index 000000000000..4e01490e51e5
--- /dev/null
+++ b/tools/perf/util/cpumap.c
@@ -0,0 +1,59 @@
+#include "util.h"
+#include "../perf.h"
+#include "cpumap.h"
+#include <assert.h>
+#include <stdio.h>
+
+int cpumap[MAX_NR_CPUS];
+
+static int default_cpu_map(void)
+{
+	int nr_cpus, i;
+
+	nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+	assert(nr_cpus <= MAX_NR_CPUS);
+	assert((int)nr_cpus >= 0);
+
+	for (i = 0; i < nr_cpus; ++i)
+		cpumap[i] = i;
+
+	return nr_cpus;
+}
+
+int read_cpu_map(void)
+{
+	FILE *onlnf;
+	int nr_cpus = 0;
+	int n, cpu, prev;
+	char sep;
+
+	onlnf = fopen("/sys/devices/system/cpu/online", "r");
+	if (!onlnf)
+		return default_cpu_map();
+
+	sep = 0;
+	prev = -1;
+	for (;;) {
+		n = fscanf(onlnf, "%u%c", &cpu, &sep);
+		if (n <= 0)
+			break;
+		if (prev >= 0) {
+			assert(nr_cpus + cpu - prev - 1 < MAX_NR_CPUS);
+			while (++prev < cpu)
+				cpumap[nr_cpus++] = prev;
+		}
+		assert (nr_cpus < MAX_NR_CPUS);
+		cpumap[nr_cpus++] = cpu;
+		if (n == 2 && sep == '-')
+			prev = cpu;
+		else
+			prev = -1;
+		if (n == 1 || sep == '\n')
+			break;
+	}
+	fclose(onlnf);
+	if (nr_cpus > 0)
+		return nr_cpus;
+
+	return default_cpu_map();
+}