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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>
This commit is contained in:
Len Brown 2012-11-08 22:38:05 -05:00
parent 3fc808aaa0
commit e52966c084
1 changed files with 10 additions and 1 deletions
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11
tools/power/x86/turbostat/turbostat.c
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@ -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) {