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Commit e52966c0 authored by Len Brown's avatar Len Brown
Browse files

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: default avatarLen Brown <len.brown@intel.com>
parent 3fc808aa

tools/power/x86/turbostat/turbostat.c

+10 −1
Original line number Diff line number Diff line
@@ -656,8 +656,10 @@ int get_counters(struct thread_data *t, struct core_data *c, struct pkg_data *p) 
{

	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 @@ int mark_cpu_present(int cpu) 
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) {