@@ -1795,6 +1795,10 @@ void native_play_dead(void)
* which would ignore the entire turbo range (a conspicuous part, making
* freq_curr/freq_max always maxed out).
*
+ * An exception to the heuristic above is the Atom uarch, where we choose the
+ * highest turbo level for freq_max since Atom's are generally oriented towards
+ * power efficiency.
+ *
* Setting freq_max to anything less than the 1C turbo ratio makes the ratio
* freq_curr / freq_max to eventually grow >1, in which case we clip it to 1.
*/
@@ -1937,18 +1941,18 @@ static bool intel_set_max_freq_ratio(void)
/*
* TODO: add support for:
*
- * - Atom Goldmont
* - Atom Silvermont
*/
u64 base_freq = 1, turbo_freq = 1;
- if (x86_match_cpu(has_glm_turbo_ratio_limits))
- return false;
-
if (turbo_disabled())
goto out;
+ if (x86_match_cpu(has_glm_turbo_ratio_limits) &&
+ skx_set_max_freq_ratio(&base_freq, &turbo_freq, 1))
+ goto out;
+
if (knl_set_max_freq_ratio(&base_freq, &turbo_freq, 1))
goto out;
The scheduler needs the ratio freq_curr/freq_max for frequency-invariant accounting. On GOLDMONT (aka Apollo Lake), GOLDMONT_D (aka Denverton) and GOLDMONT_PLUS CPUs (aka Gemini Lake) set freq_max to the highest frequency reported by the CPU. The encoding of turbo ratios for GOLDMONT* is identical to the one for SKYLAKE_X, but we treat the Atom case apart because we want to set freq_max to a higher value, thus the ratio freq_curr/freq_max to be lower, leading to more conservative frequency selections (favoring power efficiency). Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz> --- arch/x86/kernel/smpboot.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)