tools/power turbostat: prevent infinite loop on migration error path
Turbostat assumed if it can't migrate to a CPU, then the CPU
must have gone off-line and turbostat should re-initialize
with the new topology.
But if turbostat can not migrate because it is restricted by
a cpuset, then it will fail to migrate even after re-initialization,
resulting in an infinite loop.
Spit out a warning when we can't migrate
and endure only 2 re-initialize cycles in a row
before giving up and exiting.
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 3c063a0..77e76b1 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -656,8 +656,10 @@
{
int cpu = t->cpu_id;
- if (cpu_migrate(cpu))
+ if (cpu_migrate(cpu)) {
+ fprintf(stderr, "Could not migrate to CPU %d\n", cpu);
return -1;
+ }
t->tsc = rdtsc(); /* we are running on local CPU of interest */
@@ -1088,15 +1090,22 @@
void turbostat_loop()
{
int retval;
+ int restarted = 0;
restart:
+ restarted++;
+
retval = for_all_cpus(get_counters, EVEN_COUNTERS);
if (retval < -1) {
exit(retval);
} else if (retval == -1) {
+ if (restarted > 1) {
+ exit(retval);
+ }
re_initialize();
goto restart;
}
+ restarted = 0;
gettimeofday(&tv_even, (struct timezone *)NULL);
while (1) {