On Wed, Feb 3, 2021 at 2:53 PM Giovanni Gherdovich <ggherdovich@xxxxxxx> wrote: > [cut] > Fixes: 41ea667227ba ("x86, sched: Calculate frequency invariance for AMD systems") > Fixes: 976df7e5730e ("x86, sched: Use midpoint of max_boost and max_P for frequency invariance on AMD EPYC") > Reported-by: Michael Larabel <Michael@xxxxxxxxxxxx> > Tested-by: Michael Larabel <Michael@xxxxxxxxxxxx> > Signed-off-by: Giovanni Gherdovich <ggherdovich@xxxxxxx> > --- > drivers/cpufreq/acpi-cpufreq.c | 61 ++++++++++++++++++++++++++++++-- > drivers/cpufreq/cpufreq.c | 3 ++ > include/linux/cpufreq.h | 5 +++ > kernel/sched/cpufreq_schedutil.c | 8 +++-- I don't really think that it is necessary to modify schedutil to address this issue. > 4 files changed, 73 insertions(+), 4 deletions(-) > > diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c > index 1e4fbb002a31..a5facc6cad16 100644 > --- a/drivers/cpufreq/acpi-cpufreq.c > +++ b/drivers/cpufreq/acpi-cpufreq.c > @@ -26,6 +26,7 @@ > #include <linux/uaccess.h> > > #include <acpi/processor.h> > +#include <acpi/cppc_acpi.h> > > #include <asm/msr.h> > #include <asm/processor.h> > @@ -628,11 +629,57 @@ static int acpi_cpufreq_blacklist(struct cpuinfo_x86 *c) > } > #endif > > +#ifdef CONFIG_ACPI_CPPC_LIB > +static bool amd_max_boost(unsigned int max_freq, > + unsigned int *max_boost) Is there anything specific to AMD CPUs in this function? > +{ > + struct cppc_perf_caps perf_caps; > + u64 highest_perf, nominal_perf, perf_ratio; > + int ret; > + > + ret = cppc_get_perf_caps(0, &perf_caps); > + if (ret) { > + pr_debug("Could not retrieve perf counters (%d)\n", ret); > + return false; > + } > + > + highest_perf = perf_caps.highest_perf; > + nominal_perf = perf_caps.nominal_perf; > + > + if (!highest_perf || !nominal_perf) { > + pr_debug("Could not retrieve highest or nominal performance\n"); > + return false; > + } > + > + perf_ratio = div_u64(highest_perf * SCHED_CAPACITY_SCALE, nominal_perf); Why do you use SCHED_CAPACITY_SCALE here? And why does this multiply instead of shifting? > + if (perf_ratio <= SCHED_CAPACITY_SCALE) { > + pr_debug("Either perf_ratio is 0, or nominal >= highest performance\n"); > + return false; > + } > + > + *max_boost = max_freq * perf_ratio >> SCHED_CAPACITY_SHIFT; Is this assuming that max_freq corresponds to nominal_perf? > + if (!*max_boost) { > + pr_debug("max_boost seems to be zero\n"); > + return false; So this function may just return the max_boost value with 0 meaning a failure. > + } > + > + return true; > +} > +#else > +static bool amd_max_boost(unsigned int max_freq, > + unsigned int *max_boost) > +{ > + return false; > +} > +#endif > + > static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy) > { > unsigned int i; > unsigned int valid_states = 0; > unsigned int cpu = policy->cpu; > + unsigned int freq, max_freq = 0; > + unsigned int max_boost; > struct acpi_cpufreq_data *data; > unsigned int result = 0; > struct cpuinfo_x86 *c = &cpu_data(policy->cpu); > @@ -779,15 +826,25 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy) > freq_table[valid_states-1].frequency / 1000) > continue; > > + freq = perf->states[i].core_frequency * 1000; > freq_table[valid_states].driver_data = i; > - freq_table[valid_states].frequency = > - perf->states[i].core_frequency * 1000; > + freq_table[valid_states].frequency = freq; > + > + if (freq > max_freq) > + max_freq = freq; > + > valid_states++; > } > freq_table[valid_states].frequency = CPUFREQ_TABLE_END; > policy->freq_table = freq_table; > perf->state = 0; > > + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD && > + amd_max_boost(max_freq, &max_boost)) { AFAICS, the issue is not limited to AMD CPUs . > + policy->cpuinfo.max_boost = max_boost; > + static_branch_enable(&cpufreq_amd_max_boost); > + } > + > switch (perf->control_register.space_id) { > case ACPI_ADR_SPACE_SYSTEM_IO: > /* > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index d0a3525ce27f..b96677f6b57e 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -2721,6 +2721,9 @@ int cpufreq_boost_enabled(void) > } > EXPORT_SYMBOL_GPL(cpufreq_boost_enabled); > > +DEFINE_STATIC_KEY_FALSE(cpufreq_amd_max_boost); > +EXPORT_SYMBOL_GPL(cpufreq_amd_max_boost); > + > /********************************************************************* > * REGISTER / UNREGISTER CPUFREQ DRIVER * > *********************************************************************/ > diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h > index 9c8b7437b6cd..341cac76d254 100644 > --- a/include/linux/cpufreq.h > +++ b/include/linux/cpufreq.h > @@ -40,9 +40,14 @@ enum cpufreq_table_sorting { > CPUFREQ_TABLE_SORTED_DESCENDING > }; > > +DECLARE_STATIC_KEY_FALSE(cpufreq_amd_max_boost); > + > +#define cpufreq_driver_has_max_boost() static_branch_unlikely(&cpufreq_amd_max_boost) > + > struct cpufreq_cpuinfo { > unsigned int max_freq; > unsigned int min_freq; > + unsigned int max_boost; > > /* in 10^(-9) s = nanoseconds */ > unsigned int transition_latency; > diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c > index 6931f0cdeb80..541f3db3f576 100644 > --- a/kernel/sched/cpufreq_schedutil.c > +++ b/kernel/sched/cpufreq_schedutil.c > @@ -159,8 +159,12 @@ static unsigned int get_next_freq(struct sugov_policy *sg_policy, > unsigned long util, unsigned long max) > { > struct cpufreq_policy *policy = sg_policy->policy; > - unsigned int freq = arch_scale_freq_invariant() ? > - policy->cpuinfo.max_freq : policy->cur; > + unsigned int freq, max_freq; > + > + max_freq = cpufreq_driver_has_max_boost() ? > + policy->cpuinfo.max_boost : policy->cpuinfo.max_freq; > + > + freq = arch_scale_freq_invariant() ? max_freq : policy->cur; > > freq = map_util_freq(util, freq, max); > > --