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-rw-r--r--tools/perf/util/cpumap.c59
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();
+}