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linux-next/include/linux/pm_qos.h

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#ifndef _LINUX_PM_QOS_H
#define _LINUX_PM_QOS_H
pm qos infrastructure and interface The following patch is a generalization of the latency.c implementation done by Arjan last year. It provides infrastructure for more than one parameter, and exposes a user mode interface for processes to register pm_qos expectations of processes. This interface provides a kernel and user mode interface for registering performance expectations by drivers, subsystems and user space applications on one of the parameters. Currently we have {cpu_dma_latency, network_latency, network_throughput} as the initial set of pm_qos parameters. The infrastructure exposes multiple misc device nodes one per implemented parameter. The set of parameters implement is defined by pm_qos_power_init() and pm_qos_params.h. This is done because having the available parameters being runtime configurable or changeable from a driver was seen as too easy to abuse. For each parameter a list of performance requirements is maintained along with an aggregated target value. The aggregated target value is updated with changes to the requirement list or elements of the list. Typically the aggregated target value is simply the max or min of the requirement values held in the parameter list elements. >From kernel mode the use of this interface is simple: pm_qos_add_requirement(param_id, name, target_value): Will insert a named element in the list for that identified PM_QOS parameter with the target value. Upon change to this list the new target is recomputed and any registered notifiers are called only if the target value is now different. pm_qos_update_requirement(param_id, name, new_target_value): Will search the list identified by the param_id for the named list element and then update its target value, calling the notification tree if the aggregated target is changed. with that name is already registered. pm_qos_remove_requirement(param_id, name): Will search the identified list for the named element and remove it, after removal it will update the aggregate target and call the notification tree if the target was changed as a result of removing the named requirement. >From user mode: Only processes can register a pm_qos requirement. To provide for automatic cleanup for process the interface requires the process to register its parameter requirements in the following way: To register the default pm_qos target for the specific parameter, the process must open one of /dev/[cpu_dma_latency, network_latency, network_throughput] As long as the device node is held open that process has a registered requirement on the parameter. The name of the requirement is "process_<PID>" derived from the current->pid from within the open system call. To change the requested target value the process needs to write a s32 value to the open device node. This translates to a pm_qos_update_requirement call. To remove the user mode request for a target value simply close the device node. [akpm@linux-foundation.org: fix warnings] [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: fix build again] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: mark gross <mgross@linux.intel.com> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Len Brown <lenb@kernel.org> Cc: Jaroslav Kysela <perex@suse.cz> Cc: Takashi Iwai <tiwai@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com> Cc: Adam Belay <abelay@novell.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 14:30:08 +08:00
/* interface for the pm_qos_power infrastructure of the linux kernel.
*
* Mark Gross <mgross@linux.intel.com>
pm qos infrastructure and interface The following patch is a generalization of the latency.c implementation done by Arjan last year. It provides infrastructure for more than one parameter, and exposes a user mode interface for processes to register pm_qos expectations of processes. This interface provides a kernel and user mode interface for registering performance expectations by drivers, subsystems and user space applications on one of the parameters. Currently we have {cpu_dma_latency, network_latency, network_throughput} as the initial set of pm_qos parameters. The infrastructure exposes multiple misc device nodes one per implemented parameter. The set of parameters implement is defined by pm_qos_power_init() and pm_qos_params.h. This is done because having the available parameters being runtime configurable or changeable from a driver was seen as too easy to abuse. For each parameter a list of performance requirements is maintained along with an aggregated target value. The aggregated target value is updated with changes to the requirement list or elements of the list. Typically the aggregated target value is simply the max or min of the requirement values held in the parameter list elements. >From kernel mode the use of this interface is simple: pm_qos_add_requirement(param_id, name, target_value): Will insert a named element in the list for that identified PM_QOS parameter with the target value. Upon change to this list the new target is recomputed and any registered notifiers are called only if the target value is now different. pm_qos_update_requirement(param_id, name, new_target_value): Will search the list identified by the param_id for the named list element and then update its target value, calling the notification tree if the aggregated target is changed. with that name is already registered. pm_qos_remove_requirement(param_id, name): Will search the identified list for the named element and remove it, after removal it will update the aggregate target and call the notification tree if the target was changed as a result of removing the named requirement. >From user mode: Only processes can register a pm_qos requirement. To provide for automatic cleanup for process the interface requires the process to register its parameter requirements in the following way: To register the default pm_qos target for the specific parameter, the process must open one of /dev/[cpu_dma_latency, network_latency, network_throughput] As long as the device node is held open that process has a registered requirement on the parameter. The name of the requirement is "process_<PID>" derived from the current->pid from within the open system call. To change the requested target value the process needs to write a s32 value to the open device node. This translates to a pm_qos_update_requirement call. To remove the user mode request for a target value simply close the device node. [akpm@linux-foundation.org: fix warnings] [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: fix build again] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: mark gross <mgross@linux.intel.com> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Len Brown <lenb@kernel.org> Cc: Jaroslav Kysela <perex@suse.cz> Cc: Takashi Iwai <tiwai@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com> Cc: Adam Belay <abelay@novell.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 14:30:08 +08:00
*/
#include <linux/plist.h>
pm qos infrastructure and interface The following patch is a generalization of the latency.c implementation done by Arjan last year. It provides infrastructure for more than one parameter, and exposes a user mode interface for processes to register pm_qos expectations of processes. This interface provides a kernel and user mode interface for registering performance expectations by drivers, subsystems and user space applications on one of the parameters. Currently we have {cpu_dma_latency, network_latency, network_throughput} as the initial set of pm_qos parameters. The infrastructure exposes multiple misc device nodes one per implemented parameter. The set of parameters implement is defined by pm_qos_power_init() and pm_qos_params.h. This is done because having the available parameters being runtime configurable or changeable from a driver was seen as too easy to abuse. For each parameter a list of performance requirements is maintained along with an aggregated target value. The aggregated target value is updated with changes to the requirement list or elements of the list. Typically the aggregated target value is simply the max or min of the requirement values held in the parameter list elements. >From kernel mode the use of this interface is simple: pm_qos_add_requirement(param_id, name, target_value): Will insert a named element in the list for that identified PM_QOS parameter with the target value. Upon change to this list the new target is recomputed and any registered notifiers are called only if the target value is now different. pm_qos_update_requirement(param_id, name, new_target_value): Will search the list identified by the param_id for the named list element and then update its target value, calling the notification tree if the aggregated target is changed. with that name is already registered. pm_qos_remove_requirement(param_id, name): Will search the identified list for the named element and remove it, after removal it will update the aggregate target and call the notification tree if the target was changed as a result of removing the named requirement. >From user mode: Only processes can register a pm_qos requirement. To provide for automatic cleanup for process the interface requires the process to register its parameter requirements in the following way: To register the default pm_qos target for the specific parameter, the process must open one of /dev/[cpu_dma_latency, network_latency, network_throughput] As long as the device node is held open that process has a registered requirement on the parameter. The name of the requirement is "process_<PID>" derived from the current->pid from within the open system call. To change the requested target value the process needs to write a s32 value to the open device node. This translates to a pm_qos_update_requirement call. To remove the user mode request for a target value simply close the device node. [akpm@linux-foundation.org: fix warnings] [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: fix build again] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: mark gross <mgross@linux.intel.com> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Len Brown <lenb@kernel.org> Cc: Jaroslav Kysela <perex@suse.cz> Cc: Takashi Iwai <tiwai@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com> Cc: Adam Belay <abelay@novell.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 14:30:08 +08:00
#include <linux/notifier.h>
#include <linux/miscdevice.h>
#include <linux/device.h>
pm qos infrastructure and interface The following patch is a generalization of the latency.c implementation done by Arjan last year. It provides infrastructure for more than one parameter, and exposes a user mode interface for processes to register pm_qos expectations of processes. This interface provides a kernel and user mode interface for registering performance expectations by drivers, subsystems and user space applications on one of the parameters. Currently we have {cpu_dma_latency, network_latency, network_throughput} as the initial set of pm_qos parameters. The infrastructure exposes multiple misc device nodes one per implemented parameter. The set of parameters implement is defined by pm_qos_power_init() and pm_qos_params.h. This is done because having the available parameters being runtime configurable or changeable from a driver was seen as too easy to abuse. For each parameter a list of performance requirements is maintained along with an aggregated target value. The aggregated target value is updated with changes to the requirement list or elements of the list. Typically the aggregated target value is simply the max or min of the requirement values held in the parameter list elements. >From kernel mode the use of this interface is simple: pm_qos_add_requirement(param_id, name, target_value): Will insert a named element in the list for that identified PM_QOS parameter with the target value. Upon change to this list the new target is recomputed and any registered notifiers are called only if the target value is now different. pm_qos_update_requirement(param_id, name, new_target_value): Will search the list identified by the param_id for the named list element and then update its target value, calling the notification tree if the aggregated target is changed. with that name is already registered. pm_qos_remove_requirement(param_id, name): Will search the identified list for the named element and remove it, after removal it will update the aggregate target and call the notification tree if the target was changed as a result of removing the named requirement. >From user mode: Only processes can register a pm_qos requirement. To provide for automatic cleanup for process the interface requires the process to register its parameter requirements in the following way: To register the default pm_qos target for the specific parameter, the process must open one of /dev/[cpu_dma_latency, network_latency, network_throughput] As long as the device node is held open that process has a registered requirement on the parameter. The name of the requirement is "process_<PID>" derived from the current->pid from within the open system call. To change the requested target value the process needs to write a s32 value to the open device node. This translates to a pm_qos_update_requirement call. To remove the user mode request for a target value simply close the device node. [akpm@linux-foundation.org: fix warnings] [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: fix build again] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: mark gross <mgross@linux.intel.com> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Len Brown <lenb@kernel.org> Cc: Jaroslav Kysela <perex@suse.cz> Cc: Takashi Iwai <tiwai@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com> Cc: Adam Belay <abelay@novell.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 14:30:08 +08:00
#define PM_QOS_RESERVED 0
#define PM_QOS_CPU_DMA_LATENCY 1
#define PM_QOS_NETWORK_LATENCY 2
#define PM_QOS_NETWORK_THROUGHPUT 3
#define PM_QOS_NUM_CLASSES 4
#define PM_QOS_DEFAULT_VALUE -1
idle governor: Avoid lock acquisition to read pm_qos before entering idle Thanks to the reviews and comments by Rafael, James, Mark and Andi. Here's version 2 of the patch incorporating your comments and also some update to my previous patch comments. I noticed that before entering idle state, the menu idle governor will look up the current pm_qos target value according to the list of qos requests received. This look up currently needs the acquisition of a lock to access the list of qos requests to find the qos target value, slowing down the entrance into idle state due to contention by multiple cpus to access this list. The contention is severe when there are a lot of cpus waking and going into idle. For example, for a simple workload that has 32 pair of processes ping ponging messages to each other, where 64 cpu cores are active in test system, I see the following profile with 37.82% of cpu cycles spent in contention of pm_qos_lock: - 37.82% swapper [kernel.kallsyms] [k] _raw_spin_lock_irqsave - _raw_spin_lock_irqsave - 95.65% pm_qos_request menu_select cpuidle_idle_call - cpu_idle 99.98% start_secondary A better approach will be to cache the updated pm_qos target value so reading it does not require lock acquisition as in the patch below. With this patch the contention for pm_qos_lock is removed and I saw a 2.2X increase in throughput for my message passing workload. cc: stable@kernel.org Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: James Bottomley <James.Bottomley@suse.de> Acked-by: mark gross <markgross@thegnar.org> Signed-off-by: Len Brown <len.brown@intel.com>
2011-02-12 04:49:04 +08:00
#define PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC)
#define PM_QOS_NETWORK_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC)
#define PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE 0
#define PM_QOS_DEV_LAT_DEFAULT_VALUE 0
idle governor: Avoid lock acquisition to read pm_qos before entering idle Thanks to the reviews and comments by Rafael, James, Mark and Andi. Here's version 2 of the patch incorporating your comments and also some update to my previous patch comments. I noticed that before entering idle state, the menu idle governor will look up the current pm_qos target value according to the list of qos requests received. This look up currently needs the acquisition of a lock to access the list of qos requests to find the qos target value, slowing down the entrance into idle state due to contention by multiple cpus to access this list. The contention is severe when there are a lot of cpus waking and going into idle. For example, for a simple workload that has 32 pair of processes ping ponging messages to each other, where 64 cpu cores are active in test system, I see the following profile with 37.82% of cpu cycles spent in contention of pm_qos_lock: - 37.82% swapper [kernel.kallsyms] [k] _raw_spin_lock_irqsave - _raw_spin_lock_irqsave - 95.65% pm_qos_request menu_select cpuidle_idle_call - cpu_idle 99.98% start_secondary A better approach will be to cache the updated pm_qos target value so reading it does not require lock acquisition as in the patch below. With this patch the contention for pm_qos_lock is removed and I saw a 2.2X increase in throughput for my message passing workload. cc: stable@kernel.org Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: James Bottomley <James.Bottomley@suse.de> Acked-by: mark gross <markgross@thegnar.org> Signed-off-by: Len Brown <len.brown@intel.com>
2011-02-12 04:49:04 +08:00
struct pm_qos_request {
struct plist_node node;
int pm_qos_class;
};
pm qos infrastructure and interface The following patch is a generalization of the latency.c implementation done by Arjan last year. It provides infrastructure for more than one parameter, and exposes a user mode interface for processes to register pm_qos expectations of processes. This interface provides a kernel and user mode interface for registering performance expectations by drivers, subsystems and user space applications on one of the parameters. Currently we have {cpu_dma_latency, network_latency, network_throughput} as the initial set of pm_qos parameters. The infrastructure exposes multiple misc device nodes one per implemented parameter. The set of parameters implement is defined by pm_qos_power_init() and pm_qos_params.h. This is done because having the available parameters being runtime configurable or changeable from a driver was seen as too easy to abuse. For each parameter a list of performance requirements is maintained along with an aggregated target value. The aggregated target value is updated with changes to the requirement list or elements of the list. Typically the aggregated target value is simply the max or min of the requirement values held in the parameter list elements. >From kernel mode the use of this interface is simple: pm_qos_add_requirement(param_id, name, target_value): Will insert a named element in the list for that identified PM_QOS parameter with the target value. Upon change to this list the new target is recomputed and any registered notifiers are called only if the target value is now different. pm_qos_update_requirement(param_id, name, new_target_value): Will search the list identified by the param_id for the named list element and then update its target value, calling the notification tree if the aggregated target is changed. with that name is already registered. pm_qos_remove_requirement(param_id, name): Will search the identified list for the named element and remove it, after removal it will update the aggregate target and call the notification tree if the target was changed as a result of removing the named requirement. >From user mode: Only processes can register a pm_qos requirement. To provide for automatic cleanup for process the interface requires the process to register its parameter requirements in the following way: To register the default pm_qos target for the specific parameter, the process must open one of /dev/[cpu_dma_latency, network_latency, network_throughput] As long as the device node is held open that process has a registered requirement on the parameter. The name of the requirement is "process_<PID>" derived from the current->pid from within the open system call. To change the requested target value the process needs to write a s32 value to the open device node. This translates to a pm_qos_update_requirement call. To remove the user mode request for a target value simply close the device node. [akpm@linux-foundation.org: fix warnings] [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: fix build again] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: mark gross <mgross@linux.intel.com> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Len Brown <lenb@kernel.org> Cc: Jaroslav Kysela <perex@suse.cz> Cc: Takashi Iwai <tiwai@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com> Cc: Adam Belay <abelay@novell.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 14:30:08 +08:00
struct dev_pm_qos_request {
struct plist_node node;
struct device *dev;
};
enum pm_qos_type {
PM_QOS_UNITIALIZED,
PM_QOS_MAX, /* return the largest value */
PM_QOS_MIN /* return the smallest value */
};
/*
* Note: The lockless read path depends on the CPU accessing
* target_value atomically. Atomic access is only guaranteed on all CPU
* types linux supports for 32 bit quantites
*/
struct pm_qos_constraints {
struct plist_head list;
s32 target_value; /* Do not change to 64 bit */
s32 default_value;
enum pm_qos_type type;
struct blocking_notifier_head *notifiers;
};
/* Action requested to pm_qos_update_target */
enum pm_qos_req_action {
PM_QOS_ADD_REQ, /* Add a new request */
PM_QOS_UPDATE_REQ, /* Update an existing request */
PM_QOS_REMOVE_REQ /* Remove an existing request */
};
static inline int dev_pm_qos_request_active(struct dev_pm_qos_request *req)
{
return req->dev != 0;
}
#ifdef CONFIG_PM
int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
enum pm_qos_req_action action, int value);
void pm_qos_add_request(struct pm_qos_request *req, int pm_qos_class,
s32 value);
void pm_qos_update_request(struct pm_qos_request *req,
s32 new_value);
void pm_qos_remove_request(struct pm_qos_request *req);
pm qos infrastructure and interface The following patch is a generalization of the latency.c implementation done by Arjan last year. It provides infrastructure for more than one parameter, and exposes a user mode interface for processes to register pm_qos expectations of processes. This interface provides a kernel and user mode interface for registering performance expectations by drivers, subsystems and user space applications on one of the parameters. Currently we have {cpu_dma_latency, network_latency, network_throughput} as the initial set of pm_qos parameters. The infrastructure exposes multiple misc device nodes one per implemented parameter. The set of parameters implement is defined by pm_qos_power_init() and pm_qos_params.h. This is done because having the available parameters being runtime configurable or changeable from a driver was seen as too easy to abuse. For each parameter a list of performance requirements is maintained along with an aggregated target value. The aggregated target value is updated with changes to the requirement list or elements of the list. Typically the aggregated target value is simply the max or min of the requirement values held in the parameter list elements. >From kernel mode the use of this interface is simple: pm_qos_add_requirement(param_id, name, target_value): Will insert a named element in the list for that identified PM_QOS parameter with the target value. Upon change to this list the new target is recomputed and any registered notifiers are called only if the target value is now different. pm_qos_update_requirement(param_id, name, new_target_value): Will search the list identified by the param_id for the named list element and then update its target value, calling the notification tree if the aggregated target is changed. with that name is already registered. pm_qos_remove_requirement(param_id, name): Will search the identified list for the named element and remove it, after removal it will update the aggregate target and call the notification tree if the target was changed as a result of removing the named requirement. >From user mode: Only processes can register a pm_qos requirement. To provide for automatic cleanup for process the interface requires the process to register its parameter requirements in the following way: To register the default pm_qos target for the specific parameter, the process must open one of /dev/[cpu_dma_latency, network_latency, network_throughput] As long as the device node is held open that process has a registered requirement on the parameter. The name of the requirement is "process_<PID>" derived from the current->pid from within the open system call. To change the requested target value the process needs to write a s32 value to the open device node. This translates to a pm_qos_update_requirement call. To remove the user mode request for a target value simply close the device node. [akpm@linux-foundation.org: fix warnings] [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: fix build again] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: mark gross <mgross@linux.intel.com> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Len Brown <lenb@kernel.org> Cc: Jaroslav Kysela <perex@suse.cz> Cc: Takashi Iwai <tiwai@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com> Cc: Adam Belay <abelay@novell.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 14:30:08 +08:00
int pm_qos_request(int pm_qos_class);
int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier);
int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier);
int pm_qos_request_active(struct pm_qos_request *req);
s32 pm_qos_read_value(struct pm_qos_constraints *c);
s32 dev_pm_qos_read_value(struct device *dev);
int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
s32 value);
int dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value);
int dev_pm_qos_remove_request(struct dev_pm_qos_request *req);
int dev_pm_qos_add_notifier(struct device *dev,
struct notifier_block *notifier);
int dev_pm_qos_remove_notifier(struct device *dev,
struct notifier_block *notifier);
int dev_pm_qos_add_global_notifier(struct notifier_block *notifier);
int dev_pm_qos_remove_global_notifier(struct notifier_block *notifier);
void dev_pm_qos_constraints_init(struct device *dev);
void dev_pm_qos_constraints_destroy(struct device *dev);
#else
static inline int pm_qos_update_target(struct pm_qos_constraints *c,
struct plist_node *node,
enum pm_qos_req_action action,
int value)
{ return 0; }
static inline void pm_qos_add_request(struct pm_qos_request *req,
int pm_qos_class, s32 value)
{ return; }
static inline void pm_qos_update_request(struct pm_qos_request *req,
s32 new_value)
{ return; }
static inline void pm_qos_remove_request(struct pm_qos_request *req)
{ return; }
static inline int pm_qos_request(int pm_qos_class)
{ return 0; }
static inline int pm_qos_add_notifier(int pm_qos_class,
struct notifier_block *notifier)
{ return 0; }
static inline int pm_qos_remove_notifier(int pm_qos_class,
struct notifier_block *notifier)
{ return 0; }
static inline int pm_qos_request_active(struct pm_qos_request *req)
{ return 0; }
static inline s32 pm_qos_read_value(struct pm_qos_constraints *c)
{ return 0; }
static inline s32 dev_pm_qos_read_value(struct device *dev)
{ return 0; }
static inline int dev_pm_qos_add_request(struct device *dev,
struct dev_pm_qos_request *req,
s32 value)
{ return 0; }
static inline int dev_pm_qos_update_request(struct dev_pm_qos_request *req,
s32 new_value)
{ return 0; }
static inline int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
{ return 0; }
static inline int dev_pm_qos_add_notifier(struct device *dev,
struct notifier_block *notifier)
{ return 0; }
static inline int dev_pm_qos_remove_notifier(struct device *dev,
struct notifier_block *notifier)
{ return 0; }
static inline int dev_pm_qos_add_global_notifier(
struct notifier_block *notifier)
{ return 0; }
static inline int dev_pm_qos_remove_global_notifier(
struct notifier_block *notifier)
{ return 0; }
static inline void dev_pm_qos_constraints_init(struct device *dev)
{
dev->power.power_state = PMSG_ON;
}
static inline void dev_pm_qos_constraints_destroy(struct device *dev)
{
dev->power.power_state = PMSG_INVALID;
}
#endif
pm qos infrastructure and interface The following patch is a generalization of the latency.c implementation done by Arjan last year. It provides infrastructure for more than one parameter, and exposes a user mode interface for processes to register pm_qos expectations of processes. This interface provides a kernel and user mode interface for registering performance expectations by drivers, subsystems and user space applications on one of the parameters. Currently we have {cpu_dma_latency, network_latency, network_throughput} as the initial set of pm_qos parameters. The infrastructure exposes multiple misc device nodes one per implemented parameter. The set of parameters implement is defined by pm_qos_power_init() and pm_qos_params.h. This is done because having the available parameters being runtime configurable or changeable from a driver was seen as too easy to abuse. For each parameter a list of performance requirements is maintained along with an aggregated target value. The aggregated target value is updated with changes to the requirement list or elements of the list. Typically the aggregated target value is simply the max or min of the requirement values held in the parameter list elements. >From kernel mode the use of this interface is simple: pm_qos_add_requirement(param_id, name, target_value): Will insert a named element in the list for that identified PM_QOS parameter with the target value. Upon change to this list the new target is recomputed and any registered notifiers are called only if the target value is now different. pm_qos_update_requirement(param_id, name, new_target_value): Will search the list identified by the param_id for the named list element and then update its target value, calling the notification tree if the aggregated target is changed. with that name is already registered. pm_qos_remove_requirement(param_id, name): Will search the identified list for the named element and remove it, after removal it will update the aggregate target and call the notification tree if the target was changed as a result of removing the named requirement. >From user mode: Only processes can register a pm_qos requirement. To provide for automatic cleanup for process the interface requires the process to register its parameter requirements in the following way: To register the default pm_qos target for the specific parameter, the process must open one of /dev/[cpu_dma_latency, network_latency, network_throughput] As long as the device node is held open that process has a registered requirement on the parameter. The name of the requirement is "process_<PID>" derived from the current->pid from within the open system call. To change the requested target value the process needs to write a s32 value to the open device node. This translates to a pm_qos_update_requirement call. To remove the user mode request for a target value simply close the device node. [akpm@linux-foundation.org: fix warnings] [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: fix build again] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: mark gross <mgross@linux.intel.com> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Len Brown <lenb@kernel.org> Cc: Jaroslav Kysela <perex@suse.cz> Cc: Takashi Iwai <tiwai@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com> Cc: Adam Belay <abelay@novell.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 14:30:08 +08:00
#endif