#include <stdint.h>
#include <rte_random.h>
#include <rte_debug.h>
#include <rte_cycles.h>

Data Structures
struct	rte_pie_params

struct	rte_pie_config

struct	rte_pie

Macros
#define	RTE_DQ_THRESHOLD 16384

#define	RTE_DQ_WEIGHT 0.25

#define	RTE_ALPHA 0.125

#define	RTE_BETA 1.25

#define	RTE_RAND_MAX ~0LLU

Functions
int	rte_pie_rt_data_init (struct rte_pie *pie)
	Initialises run-time data. More...

int	rte_pie_config_init (struct rte_pie_config *pie_cfg, const uint16_t qdelay_ref, const uint16_t dp_update_interval, const uint16_t max_burst, const uint16_t tailq_th)
	Configures a single PIE configuration parameter structure. More...

static int	rte_pie_enqueue_empty (const struct rte_pie_config pie_cfg, struct rte_pie pie, uint32_t pkt_len)
	Decides packet enqueue when queue is empty. More...

static void	_calc_drop_probability (const struct rte_pie_config pie_cfg, struct rte_pie pie, uint64_t time)
	make a decision to drop or enqueue a packet based on probability criteria More...

static int	_rte_pie_drop (const struct rte_pie_config pie_cfg, struct rte_pie pie)
	make a decision to drop or enqueue a packet based on probability criteria More...

static int	rte_pie_enqueue_nonempty (const struct rte_pie_config pie_cfg, struct rte_pie pie, uint32_t pkt_len, const uint64_t time)
	Decides if new packet should be enqueued or dropped for non-empty queue. More...

static int	rte_pie_enqueue (const struct rte_pie_config pie_cfg, struct rte_pie pie, const unsigned int qlen, uint32_t pkt_len, const uint64_t time)
	Decides if new packet should be enqueued or dropped Updates run time data and gives verdict whether to enqueue or drop the packet. More...

static void	rte_pie_dequeue (struct rte_pie *pie, uint32_t pkt_len, uint64_t time)
	PIE rate estimation method Called on each packet departure. More...

Detailed Description

Proportional Integral controller Enhanced (PIE)

Definition in file rte_pie.h.

Macro Definition Documentation

◆ RTE_DQ_THRESHOLD

#define RTE_DQ_THRESHOLD 16384

Queue length threshold (2^14) to start measurement cycle (bytes)

Definition at line 25 of file rte_pie.h.

◆ RTE_DQ_WEIGHT

#define RTE_DQ_WEIGHT 0.25

Weight (RTE_DQ_THRESHOLD/2^16) to compute dequeue rate

Definition at line 26 of file rte_pie.h.

◆ RTE_ALPHA

#define RTE_ALPHA 0.125

Weights in drop probability calculations

Definition at line 27 of file rte_pie.h.

◆ RTE_BETA

#define RTE_BETA 1.25

Weights in drop probability calculations

Definition at line 28 of file rte_pie.h.

◆ RTE_RAND_MAX

#define RTE_RAND_MAX ~0LLU

Max value of the random number

Definition at line 29 of file rte_pie.h.

Function Documentation

◆ rte_pie_rt_data_init()

int rte_pie_rt_data_init ( struct rte_pie * pie )

Initialises run-time data.

Parameters

pie	[in,out] data pointer to PIE runtime data

Returns: Operation status

Return values

0	success
!0	error

◆ rte_pie_config_init()

int rte_pie_config_init	(	struct rte_pie_config *	pie_cfg,
		const uint16_t	qdelay_ref,
		const uint16_t	dp_update_interval,
		const uint16_t	max_burst,
		const uint16_t	tailq_th
	)

Configures a single PIE configuration parameter structure.

Parameters

pie_cfg	[in,out] config pointer to a PIE configuration parameter structure
qdelay_ref	[in] latency target(milliseconds)
dp_update_interval	[in] update interval for drop probability (milliseconds)
max_burst	[in] maximum burst allowance (milliseconds)
tailq_th	[in] tail drop threshold for the queue (number of packets)

Returns: Operation status

Return values

0	success
!0	error

◆ rte_pie_enqueue_empty()

static int rte_pie_enqueue_empty	(	const struct rte_pie_config *	pie_cfg,
		struct rte_pie *	pie,
		uint32_t	pkt_len
	)

static

Decides packet enqueue when queue is empty.

Note: packet is never dropped in this particular case.

Parameters

pie_cfg	[in] config pointer to a PIE configuration parameter structure
pie	[in, out] data pointer to PIE runtime data
pkt_len	[in] packet length in bytes

Returns: Operation status

Return values

0	enqueue the packet
!0	drop the packet

If the queue has been idle for a while, turn off PIE and Reset counters

Definition at line 116 of file rte_pie.h.

◆ _calc_drop_probability()

static void _calc_drop_probability	(	const struct rte_pie_config *	pie_cfg,
		struct rte_pie *	pie,
		uint64_t	time
	)

static

make a decision to drop or enqueue a packet based on probability criteria

Parameters

pie_cfg	[in] config pointer to a PIE configuration parameter structure
pie	[in, out] data pointer to PIE runtime data
time	[in] current time (measured in cpu cycles)

Definition at line 147 of file rte_pie.h.

◆ _rte_pie_drop()

static int _rte_pie_drop	(	const struct rte_pie_config *	pie_cfg,
		struct rte_pie *	pie
	)

inlinestatic

make a decision to drop or enqueue a packet based on probability criteria

Parameters

pie_cfg	[in] config pointer to a PIE configuration parameter structure
pie	[in, out] data pointer to PIE runtime data

Returns: operation status

Return values

0	enqueue the packet
1	drop the packet

Definition at line 210 of file rte_pie.h.

◆ rte_pie_enqueue_nonempty()

static int rte_pie_enqueue_nonempty	(	const struct rte_pie_config *	pie_cfg,
		struct rte_pie *	pie,
		uint32_t	pkt_len,
		const uint64_t	time
	)

inlinestatic

Decides if new packet should be enqueued or dropped for non-empty queue.

Parameters

pie_cfg	[in] config pointer to a PIE configuration parameter structure
pie	[in,out] data pointer to PIE runtime data
pkt_len	[in] packet length in bytes
time	[in] current time (measured in cpu cycles)

Returns: Operation status

Return values

0	enqueue the packet
1	drop the packet based on max threshold criterion
2	drop the packet based on mark probability criterion

Definition at line 258 of file rte_pie.h.

◆ rte_pie_enqueue()

static int rte_pie_enqueue	(	const struct rte_pie_config *	pie_cfg,
		struct rte_pie *	pie,
		const unsigned int	qlen,
		uint32_t	pkt_len,
		const uint64_t	time
	)

inlinestatic

Decides if new packet should be enqueued or dropped Updates run time data and gives verdict whether to enqueue or drop the packet.

Parameters

pie_cfg	[in] config pointer to a PIE configuration parameter structure
pie	[in,out] data pointer to PIE runtime data
qlen	[in] queue length
pkt_len	[in] packet length in bytes
time	[in] current time stamp (measured in cpu cycles)

Returns: Operation status

Return values

0	enqueue the packet
1	drop the packet based on drop probability criteria

Definition at line 325 of file rte_pie.h.

◆ rte_pie_dequeue()

static void rte_pie_dequeue	(	struct rte_pie *	pie,
		uint32_t	pkt_len,
		uint64_t	time
	)

inlinestatic

PIE rate estimation method Called on each packet departure.

Parameters

pie	[in] data pointer to PIE runtime data
pkt_len	[in] packet length in bytes
time	[in] current time stamp in cpu cycles

Definition at line 349 of file rte_pie.h.

Data Structures

Macros

Functions

Detailed Description

Macro Definition Documentation

◆ RTE_DQ_THRESHOLD

◆ RTE_DQ_WEIGHT

◆ RTE_ALPHA

◆ RTE_BETA

◆ RTE_RAND_MAX

Function Documentation

◆ rte_pie_rt_data_init()

◆ rte_pie_config_init()

◆ rte_pie_enqueue_empty()

◆ _calc_drop_probability()

◆ _rte_pie_drop()

◆ rte_pie_enqueue_nonempty()

◆ rte_pie_enqueue()

◆ rte_pie_dequeue()