Stochastic Fairness Queueing (SFQ)

Attribute Access
int	rtnl_sfq_set_quantum (struct rtnl_qdisc *qdisc, int quantum)
	Set quantum of SFQ qdisc.
int	rtnl_sfq_get_quantum (struct rtnl_qdisc *qdisc)
	Get quantum of SFQ qdisc.
int	rtnl_sfq_set_limit (struct rtnl_qdisc *qdisc, int limit)
	Set limit of SFQ qdisc.
int	rtnl_sfq_get_limit (struct rtnl_qdisc *qdisc)
	Get limit of SFQ qdisc.
int	rtnl_sfq_set_perturb (struct rtnl_qdisc *qdisc, int perturb)
	Set perturbation interval of SFQ qdisc.
int	rtnl_sfq_get_perturb (struct rtnl_qdisc *qdisc)
	Get perturbation interval of SFQ qdisc.
int	rtnl_sfq_get_divisor (struct rtnl_qdisc *qdisc)
	Get divisor of SFQ qdisc.

---

Detailed Description

Parameter Description

• Quantum: Number of bytes to send out per slot and round.
• Perturbation: Timer period between changing the hash function.
• Limit: Upper limit of queue in number of packets before SFQ starts dropping packets.
• Divisor: Hash table divisor, i.e. size of hash table.

---

Function Documentation

int rtnl_sfq_set_quantum	(	struct rtnl_qdisc *	qdisc,
		int	quantum
	)

Parameters:

qdisc	SFQ qdisc to be modified.
quantum	New quantum in bytes.

Returns:

0 on success or a negative error code.

Definition at line 154 of file sfq.c.

{
        struct rtnl_sfq *sfq;
        
        sfq = sfq_alloc(qdisc);
        if (!sfq)
                return nl_errno(ENOMEM);

        sfq->qs_quantum = quantum;
        sfq->qs_mask |= SCH_SFQ_ATTR_QUANTUM;

        return 0;
}

int rtnl_sfq_get_quantum

(

struct rtnl_qdisc *

qdisc

)

Parameters:

qdisc

SFQ qdisc.

Returns:

Quantum in bytes or a negative error code.

Definition at line 173 of file sfq.c.

{
        struct rtnl_sfq *sfq;

        sfq = sfq_qdisc(qdisc);
        if (sfq && sfq->qs_mask & SCH_SFQ_ATTR_QUANTUM)
                return sfq->qs_quantum;
        else
                return nl_errno(ENOENT);
}

int rtnl_sfq_set_limit	(	struct rtnl_qdisc *	qdisc,
		int	limit
	)

Parameters:

qdisc	SFQ qdisc to be modified.
limit	New limit in number of packets.

Returns:

0 on success or a negative error code.

Definition at line 190 of file sfq.c.

{
        struct rtnl_sfq *sfq;

        sfq = sfq_alloc(qdisc);
        if (!sfq)
                return nl_errno(ENOMEM);

        sfq->qs_limit = limit;
        sfq->qs_mask |= SCH_SFQ_ATTR_LIMIT;

        return 0;
}

int rtnl_sfq_get_limit

(

struct rtnl_qdisc *

qdisc

)

Parameters:

qdisc

SFQ qdisc.

Returns:

Limit or a negative error code.

Definition at line 209 of file sfq.c.

{
        struct rtnl_sfq *sfq;

        sfq = sfq_qdisc(qdisc);
        if (sfq && sfq->qs_mask & SCH_SFQ_ATTR_LIMIT)
                return sfq->qs_limit;
        else
                return nl_errno(ENOENT);
}

int rtnl_sfq_set_perturb	(	struct rtnl_qdisc *	qdisc,
		int	perturb
	)

Parameters:

qdisc	SFQ qdisc to be modified.
perturb	New perturbation interval in seconds.

Note:

A value of 0 disables perturbation altogether.

Returns:

0 on success or a negative error code.

Definition at line 227 of file sfq.c.

{
        struct rtnl_sfq *sfq;

        sfq = sfq_alloc(qdisc);
        if (!sfq)
                return nl_errno(ENOMEM);

        sfq->qs_perturb = perturb;
        sfq->qs_mask |= SCH_SFQ_ATTR_PERTURB;

        return 0;
}

int rtnl_sfq_get_perturb

(

struct rtnl_qdisc *

qdisc

)

Parameters:

qdisc

SFQ qdisc.

Returns:

Perturbation interval in seconds or a negative error code.

Definition at line 246 of file sfq.c.

{
        struct rtnl_sfq *sfq;

        sfq = sfq_qdisc(qdisc);
        if (sfq && sfq->qs_mask & SCH_SFQ_ATTR_PERTURB)
                return sfq->qs_perturb;
        else
                return nl_errno(ENOENT);
}

int rtnl_sfq_get_divisor

(

struct rtnl_qdisc *

qdisc

)

Parameters:

qdisc

SFQ qdisc.

Returns:

Divisor in number of entries or a negative error code.

Definition at line 262 of file sfq.c.

{
        struct rtnl_sfq *sfq;

        sfq = sfq_qdisc(qdisc);
        if (sfq && sfq->qs_mask & SCH_SFQ_ATTR_DIVISOR)
                return sfq->qs_divisor;
        else
                return nl_errno(ENOENT);
}