On Monday 28 January 2008 00:55, Zhao Yakui wrote:
> Subject: ACPI : Update the t-state for every affected cpu when t-state is changed
> >From : Zhao Yakui <yakui.zhao@xxxxxxxxx>
>
> According to ACPI spec, the _TSD object provides T-state control cross
> logical processor dependency information to OSPM. So the t-state
> coordination should be considered when T-state for one cpu is changed.
>
> According to ACPI spec, three types of coordination are defined.
> SW_ALL, SW_ANY and HW_ALL.
> SW_ALL: it means that OSPM needs to initiate T-state transition on
> all processors in the domain. It is necessary to call throttling set function
> for all affected cpus.
> SW_ANY: it means that OSPM may initiate T-state transition on any processor in
> the domain.
> HW_ALL: Apec only says that hardware will perform the coordination and doesn't
> recommend how OSPM coordinate T-state among the affected cpus. So it is treated
> as the type of SW_ALL. It means that OSPM needs to initiate t-state transition
> on all the processors in the domain.
>
> Signed-off-by: Zhao Yakui <yakui.zhao@xxxxxxxxx>
> ---
> drivers/acpi/processor_throttling.c | 79 +++++++++++++++++++++++++++++++++---
> 1 file changed, 74 insertions(+), 5 deletions(-)
>
> Index: linux-2.6/drivers/acpi/processor_throttling.c
> ===================================================================
> --- linux-2.6.orig/drivers/acpi/processor_throttling.c
> +++ linux-2.6/drivers/acpi/processor_throttling.c
> @@ -68,7 +68,7 @@ static int acpi_processor_update_tsd_coo
>
> /*
> * Now that we have _TSD data from all CPUs, lets setup T-state
> - * coordination among all CPUs.
> + * coordination between all CPUs.
> */
> for_each_possible_cpu(i) {
> pr = processors[i];
> @@ -988,6 +988,11 @@ int acpi_processor_set_throttling(struct
> {
> cpumask_t saved_mask;
> int ret;
> + unsigned int i;
> + struct acpi_processor *match_pr;
> + struct acpi_processor_throttling *p_throttling;
> + struct throttling_tstate t_state;
> + cpumask_t online_throttling_cpus;
>
> if (!pr)
> return -EINVAL;
> @@ -998,12 +1003,76 @@ int acpi_processor_set_throttling(struct
> if ((state < 0) || (state > (pr->throttling.state_count - 1)))
> return -EINVAL;
>
> + saved_mask = current->cpus_allowed;
> + t_state.target_state = state;
> + p_throttling = &(pr->throttling);
> + cpus_and(online_throttling_cpus, cpu_online_map,
> + p_throttling->shared_cpu_map);
> /*
> - * Migrate task to the cpu pointed by pr.
> + * The throttling notifier will be called for every
> + * affected cpu in order to get one proper T-state.
> + * The notifier event is THROTTLING_PRECHANGE.
> */
> - saved_mask = current->cpus_allowed;
> - set_cpus_allowed(current, cpumask_of_cpu(pr->id));
> - ret = pr->throttling.acpi_processor_set_throttling(pr, state);
drivers/acpi/processor_throttling.c:990: warning: ‘ret’ may be used uninitialized in this function
-Len
> + for_each_cpu_mask(i, online_throttling_cpus) {
> + t_state.cpu = i;
> + acpi_processor_throttling_notifier(THROTTLING_PRECHANGE,
> + &t_state);
> + }
> + /*
> + * The function of acpi_processor_set_throttling will be called
> + * to switch T-state. If the coordination type is SW_ALL or HW_ALL,
> + * it is necessary to call it for every affected cpu. Otherwise
> + * it can be called only for the cpu pointed by pr.
> + */
> + if (p_throttling->shared_type == DOMAIN_COORD_TYPE_SW_ANY) {
> + set_cpus_allowed(current, cpumask_of_cpu(pr->id));
> + ret = p_throttling->acpi_processor_set_throttling(pr,
> + t_state.target_state);
> + } else {
> + /*
> + * When the T-state coordination is SW_ALL or HW_ALL,
> + * it is necessary to set T-state for every affected
> + * cpus.
> + */
> + for_each_cpu_mask(i, online_throttling_cpus) {
> + match_pr = processors[i];
> + /*
> + * If the pointer is invalid, we will report the
> + * error message and continue.
> + */
> + if (!match_pr) {
> + ACPI_DEBUG_PRINT((ACPI_DB_INFO,
> + "Invalid Pointer for CPU %d\n", i));
> + continue;
> + }
> + /*
> + * If the throttling control is unsupported on CPU i,
> + * we will report the error message and continue.
> + */
> + if (!match_pr->flags.throttling) {
> + ACPI_DEBUG_PRINT((ACPI_DB_INFO,
> + "Throttling Controll is unsupported "
> + "on CPU %d\n", i));
> + continue;
> + }
> + t_state.cpu = i;
> + set_cpus_allowed(current, cpumask_of_cpu(i));
> + ret = match_pr->throttling.
> + acpi_processor_set_throttling(
> + match_pr, t_state.target_state);
> + }
> + }
> + /*
> + * After the set_throttling is called, the
> + * throttling notifier is called for every
> + * affected cpu to update the T-states.
> + * The notifier event is THROTTLING_POSTCHANGE
> + */
> + for_each_cpu_mask(i, online_throttling_cpus) {
> + t_state.cpu = i;
> + acpi_processor_throttling_notifier(THROTTLING_POSTCHANGE,
> + &t_state);
> + }
> /* restore the previous state */
> set_cpus_allowed(current, saved_mask);
> return ret;
>
>
> -
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