Re: [Xen-devel] [PATCH] AMD, powernow: Update P-state directly when _PSD's CoordType is DOMAIN_COORD_TYPE_HW_ALL

[Boris Ostrovsky <boris.ostrovsky@xxxxxxx>]

On 08/17/2012 06:31 AM, Jan Beulich wrote:
> > > > On 16.08.12 at 18:41, Boris Ostrovsky <boris.ostrovsky@xxxxxxx> wrote:
> > @@ -137,26 +122,28 @@ static int powernow_cpufreq_target(struc
> >               return 0;
> >       }
> >
> > -    if (policy->shared_type != CPUFREQ_SHARED_TYPE_ANY)
> > -        cmd.mask = &online_policy_cpus;
> > -    else
> > -        cmd.mask = cpumask_of(policy->cpu);
> > +    if (policy->shared_type == CPUFREQ_SHARED_TYPE_HW &&
> > +        likely(policy->cpu == smp_processor_id())) {
> > +        transition_pstate(&next_perf_state);
> > +        cpufreq_statistic_update(policy->cpu, perf->state, next_perf_state);
> Actually - is this enough? Doesn't this also need to be done based
> on policy->cpus?
With HW-coordinated transitions there is a policy structure per CPU so 
policy->cpus is always 1 and policy->cpu is the same as policy->cpus. 
You can see this in cpufreq_add_cpu(), when hw_all is set.
(This is consistent with ACPI spec:
        When hardware coordinates transitions, OSPM continues to
        initiate state transitions as it would if there were no
        dependencies.
)

-boris


> Jan
>
> > +    } else {
> > +        cpumask_and(&online_policy_cpus, policy->cpus, &cpu_online_map);
> >
> > -    freqs.old = perf->states[perf->state].core_frequency * 1000;
> > -    freqs.new = data->freq_table[next_state].frequency;
> > +        if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL ||
> > +            unlikely(policy->cpu != smp_processor_id()))
> > +            on_selected_cpus(&online_policy_cpus, transition_pstate,
> > +                             &next_perf_state, 1);
> > +        else
> > +            transition_pstate(&next_perf_state);
> >
> > -    cmd.val = next_perf_state;
> > -    cmd.turbo = policy->turbo;
> > -
> > -    on_selected_cpus(cmd.mask, transition_pstate, &cmd, 1);
> > -
> > -    for_each_cpu(j, &online_policy_cpus)
> > -        cpufreq_statistic_update(j, perf->state, next_perf_state);
> > +        for_each_cpu(j, &online_policy_cpus)
> > +            cpufreq_statistic_update(j, perf->state, next_perf_state);
> > +    }
> >
> >       perf->state = next_perf_state;
> > -    policy->cur = freqs.new;
> > +    policy->cur = data->freq_table[next_state].frequency;
> >
> > -    return result;
> > +    return 0;
> >   }
> >
> >   static int powernow_cpufreq_verify(struct cpufreq_policy *policy)
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxx
> > http://lists.xen.org/xen-devel

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