@@ -1991,9 +1991,11 @@ static bool intel_set_max_freq_ratio(void)
/*
* Some hypervisors advertise X86_FEATURE_APERFMPERF
* but then fill all MSR's with zeroes.
+ * Some CPUs have turbo boost but don't declare any turbo ratio
+ * in MSR_TURBO_RATIO_LIMIT.
*/
- if (!base_freq) {
- pr_debug("Couldn't determine cpu base frequency, necessary for scale-invariant accounting.\n");
+ if (!base_freq || !turbo_freq) {
+ pr_debug("Couldn't determine cpu base or turbo frequency, necessary for scale-invariant accounting.\n");
return false;
}
There may be CPUs that support turbo boost but don't declare any turbo ratio, i.e. their MSR_TURBO_RATIO_LIMIT is all zeroes. In that condition scale-invariant calculations can't be performed. Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz> Suggested-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Fixes: 1567c3e3467c ("x86, sched: Add support for frequency invariance") --- arch/x86/kernel/smpboot.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)