Moving average predictor.

Data Structures
struct	movavg_params_struct
	Parameters for movavg predictor. More...
struct	movavg_struct
	Moving Average predictor class definition. More...
Files
file	movavg.h
	Private interface for the Moving Average predictor.
file	movavg_lib.h
	Public interface for the Moving Average predictor.
Defines
#define	MAX_FORGET_F   32768
	Value of forget_f corresponding to 1.0.
#define	MAX_FORGET_F_BITS   15
	Value of forget_f corresponding to 1.0 (log_2).
#define	MOVAVG_DEF_SAMPLESIZE   3
	Default sample size.
#define	MOVAVG_DEF_FORGETF   1.0
	Default forgetting factor.
Typedefs
typedef struct movavg_params_struct	movavg_params_t
	Parameters for movavg predictor.
typedef struct movavg_struct	movavg_t
	Moving Average predictor class definition.
Functions
qos_rv	movavg_register (void)
	Register the Moving Average class with the framework.
qos_rv	movavg_init (void *self, void *params)
	Initialize a movavg object.
qos_rv	movavg_final (qmgr_pred_t *self)
	Virtual destructor for a movavg object.
qos_rv	movavg_add_sample (qmgr_pred_t *pred, qres_time_t new_sample)
	Virtual add_sample function for movavg object.
qres_time_t	movavg_get_exp_value (qmgr_pred_t *pred)
qos_rv	movavg_add_sample_ff (qmgr_pred_t *pred, qres_time_t new_sample)
qres_time_t	movavg_get_exp_value_ff (qmgr_pred_t *pred)
qos_rv	movavg_set_defaults (void)
	Configures a Moving Average predictor with default parameters.
qos_rv	movavg_set_sample_size (int sample_size)
	Sets the sample size for the Moving Average predictor.
qos_rv	movavg_set_forget_f (float ff)
	Sets a forgetting factor lower than 1.

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Define Documentation

#define MAX_FORGET_F   32768

Value of forget_f corresponding to 1.0.

== 2 ^ MAX_FORGET_F_BITS

Definition at line 17 of file movavg.h.

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Function Documentation

qos_rv movavg_add_sample	(	qmgr_pred_t *	pred,
		qres_time_t	new_sample
	)

Virtual add_sample function for movavg object.

Todo:

2 versions of this function could be created, one for the initial transitory when the window is not yet full, and another to be used when the window is full. By replacing the function pointer in the virtual table, this would avoid one comparison in the function at each call.

qos_rv movavg_init	(	void *	self,
		void *	params
	)

Initialize a movavg object.

Parameters:

params

Set of parameters passed by the QMGR Library. When in kernel-space, self is a pointer to user-space.

Returns:

QOS_OK or one of the predefined error-codes.

qos_rv movavg_set_defaults

(

void

)

Configures a Moving Average predictor with default parameters.

Tells to the QoS library to use a moving average predictor with a default set of parameters.

qos_rv movavg_set_forget_f

(

float

ff

)

Sets a forgetting factor lower than 1.

Parameters:

ff

The forgetting factor to be used, in the open range ]0,1[.

qos_rv movavg_set_sample_size

(

int

sample_size

)

Sets the sample size for the Moving Average predictor.

Parameters:

sample_size

The number of past samples on which the moving average is computed