dvfs_context.h File Reference

Describes all the structures and functions related to the whole DVFS context (the whole system). More...

Go to the source code of this file.

Data Structures
struct	dvfs_ctx
	DVFS Context. More...

Macros
#define	DVFS_TB_UNAVAILABLE   0
	TurboBoost is not available, see dvfs_has_TB()
#define	DVFS_TB_AVAILABLE   1
	TurboBoost is available, see dvfs_has_TB()

Functions
int	dvfs_start (dvfs_ctx **ppCtx, bool seq)
	Starts controlling DVFS on the system. More...
int	dvfs_stop (dvfs_ctx *ctx)
	Frees the memory associated to a DVFS context and restores the DVFS control to its state before calling dvfs_start. More...
int	dvfs_has_TB ()
	Returns true if one of the DVFS unit on the system allows TurboBoost. More...
int	dvfs_set_gov (const dvfs_ctx *ctx, const char *gov)
	Sets the provided governor on all the DVFS units. More...
int	dvfs_set_freq (dvfs_ctx *ctx, unsigned int freq)
	Sets the given frequency on all the DVFS units. More...
int	dvfs_get_core (const dvfs_ctx *ctx, const dvfs_core **ppCore, unsigned int core_id)
	Gets the dvfs_core structure associated to the given core id. More...
int	dvfs_get_unit_by_id (const dvfs_ctx *ctx, const dvfs_unit **ppUnit, unsigned int index)
	Gets the DVFS unit associated to the given index. More...
int	dvfs_get_unit_by_core (const dvfs_ctx *ctx, const dvfs_core *core, const dvfs_unit **ppUnit)
	Gets the DVFS unit associated with the given core. More...
int	dvfs_get_nb_units (const dvfs_ctx *ctx, unsigned int *pNb)
	Gets the number of DVFS units available in this context. More...

Detailed Description

Describes all the structures and functions related to the whole DVFS context (the whole system).

This is the entry point of the library.

See also

dvfs_unit

Function Documentation

int dvfs_get_core	(	const dvfs_ctx *	ctx,
		const dvfs_core **	ppCore,
		unsigned int	core_id
	)

Gets the dvfs_core structure associated to the given core id.

Parameters

ctx	The DVFS context as provided by dvfs_start()
ppCore	The dvfs_core structure associated to the core or NULL if the core id is not found.
core_id	The core id.

Returns

Return values

DVFS_SUCCESS	if everything goes right.
DVFS_ERROR_INVALID_ARG	if ctx or ppCore are NULL.
DVFS_ERROR_INVALID_CORE_ID	if the core ID is not valid.

int dvfs_get_nb_units	(	const dvfs_ctx *	ctx,
		unsigned int *	pNb
	)

Gets the number of DVFS units available in this context.

Parameters

ctx	The DVFS context as provided by dvfs_start()
pNb	Will be filled with the number of DVFS unit available

Returns

Return values

DVFS_SUCCESS	if everything goes right.
DVFS_ERROR_INVALID_ARG	if ctx or pNb are NULL.

int dvfs_get_unit_by_core	(	const dvfs_ctx *	ctx,
		const dvfs_core *	core,
		const dvfs_unit **	ppUnit
	)

Gets the DVFS unit associated with the given core.

Parameters

ctx	The DVFS context as provided by dvfs_start()
core	The core structure.
ppUnit	The DVFS unit in charge of this core.

Returns

Return values

DVFS_SUCCESS	if everything goes right.
DVFS_ERROR_INVALID_ARG	if ctx or core or ppUnit are NULL.
DVFS_ERROR_CORE_UNIT_MISMATCH	if the unit can not be find.

int dvfs_get_unit_by_id	(	const dvfs_ctx *	ctx,
		const dvfs_unit **	ppUnit,
		unsigned int	index
	)

Gets the DVFS unit associated to the given index.

Parameters

ctx	The DVFS context as provided by dvfs_start()
ppUnit	Will be filled with the DVFS unit.
index	The index of the DVFS unit to get

Returns

Return values

DVFS_SUCCESS	if everything goes right.
DVFS_ERROR_INVALID_ARG	if ctx or core or ppUnit are NULL.
DVFS_ERROR_INVALID_INDEX	if index does not match any DVFS unit.

int dvfs_has_TB

(

)

Returns true if one of the DVFS unit on the system allows TurboBoost.

Returns

Return values

DVFS_TB_AVAILABLE	if TurboBoost is available on one of the DVFS unit.
DVFS_TB_UNAVAILABLE	if TurboBoost is not available.
DVFS_ERROR_FILE_FAILED	if the information could not be read (likely because /proc/cpuinfo is not available), or can't be opened.

int dvfs_set_freq	(	dvfs_ctx *	ctx,
		unsigned int	freq
	)

Sets the given frequency on all the DVFS units.

The effects are unknown if the current governor is not "userspace".

Parameters

ctx	The DVFS context as provided by dvfs_start()
freq	The new frequency to set.

Returns

Return values

DVFS_SUCCESS	if everything goes right.
DVFS_ERROR_INVALID_ARG	if ctx is NULL.

int dvfs_set_gov	(	const dvfs_ctx *	ctx,
		const char *	gov
	)

Sets the provided governor on all the DVFS units.

Parameters

ctx	The DVFS context as provided by dvfs_start
gov	The new governor to set

Returns

Return values

DVFS_SUCCESS	if everything goes right.
DVFS_ERROR_INVALID_ARG	if ctx or gov are NULL.

int dvfs_start	(	dvfs_ctx **	ppCtx,
		bool	seq
	)

Starts controlling DVFS on the system.

Parameters

ppCtx	the new DVFS context used in the various functions.
seq	Tells if the frequency transitions must be synchronized or not.

Returns

Return values

DVFS_SUCCESS	if everything goes right.
DVFS_ERROR_INVALID_ARG	if ppCtx is NULL.
DVFS_ERROR_MEM_ALLOC_FAILED	if memory allocation failed.
DVFS_ERROR_RELATED_CORE_UNAVAILABLE	the related core information is not available

See also

dvfs_stop()

int dvfs_stop

(

dvfs_ctx *

ctx

)

Frees the memory associated to a DVFS context and restores the DVFS control to its state before calling dvfs_start.

Parameters

ctx	the context

Returns

Return values

DVFS_SUCCESS	if everything goes right.
DVFS_ERROR_INVALID_ARG	if ctx is NULL.

See also

dvfs_start()