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();
+}