The following commit has been merged into the sched/core branch of tip: Commit-ID: eacf0474aec8bdccdc7f19386319127c67be3588 Gitweb: https://git.kernel.org/tip/eacf0474aec8bdccdc7f19386319127c67be3588 Author: Giovanni Gherdovich <ggherdovich@xxxxxxx> AuthorDate: Wed, 22 Jan 2020 16:16:15 +01:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Tue, 28 Jan 2020 21:37:04 +01:00 x86, sched: Add support for frequency invariance on ATOM_GOLDMONT* 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@xxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Link: https://lkml.kernel.org/r/20200122151617.531-5-ggherdovich@xxxxxxx --- arch/x86/kernel/smpboot.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 8cb3113..3e32d62 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -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;
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