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ec97ecf1eb
Principles:
- Packets are classified on flows.
- This is a Stochastic model (as we use a hash, several flows might
be hashed to the same slot)
- Each flow has a PIE managed queue.
- Flows are linked onto two (Round Robin) lists,
so that new flows have priority on old ones.
- For a given flow, packets are not reordered.
- Drops during enqueue only.
- ECN capability is off by default.
- ECN threshold (if ECN is enabled) is at 10% by default.
- Uses timestamps to calculate queue delay by default.
Usage:
tc qdisc ... fq_pie [ limit PACKETS ] [ flows NUMBER ]
[ target TIME ] [ tupdate TIME ]
[ alpha NUMBER ] [ beta NUMBER ]
[ quantum BYTES ] [ memory_limit BYTES ]
[ ecnprob PERCENTAGE ] [ [no]ecn ]
[ [no]bytemode ] [ [no_]dq_rate_estimator ]
defaults:
limit: 10240 packets, flows: 1024
target: 15 ms, tupdate: 15 ms (in jiffies)
alpha: 1/8, beta : 5/4
quantum: device MTU, memory_limit: 32 Mb
ecnprob: 10%, ecn: off
bytemode: off, dq_rate_estimator: off
Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
Signed-off-by: Sachin D. Patil <sdp.sachin@gmail.com>
Signed-off-by: V. Saicharan <vsaicharan1998@gmail.com>
Signed-off-by: Mohit Bhasi <mohitbhasi1998@gmail.com>
Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
Signed-off-by: Gautam Ramakrishnan <gautamramk@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
139 lines
3.7 KiB
C
139 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#ifndef __NET_SCHED_PIE_H
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#define __NET_SCHED_PIE_H
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#include <linux/ktime.h>
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#include <linux/skbuff.h>
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#include <linux/types.h>
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#include <net/inet_ecn.h>
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#include <net/pkt_sched.h>
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#define MAX_PROB U64_MAX
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#define DTIME_INVALID U64_MAX
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#define QUEUE_THRESHOLD 16384
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#define DQCOUNT_INVALID -1
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#define PIE_SCALE 8
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/**
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* struct pie_params - contains pie parameters
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* @target: target delay in pschedtime
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* @tudpate: interval at which drop probability is calculated
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* @limit: total number of packets that can be in the queue
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* @alpha: parameter to control drop probability
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* @beta: parameter to control drop probability
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* @ecn: is ECN marking of packets enabled
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* @bytemode: is drop probability scaled based on pkt size
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* @dq_rate_estimator: is Little's law used for qdelay calculation
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*/
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struct pie_params {
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psched_time_t target;
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u32 tupdate;
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u32 limit;
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u32 alpha;
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u32 beta;
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u8 ecn;
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u8 bytemode;
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u8 dq_rate_estimator;
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};
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/**
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* struct pie_vars - contains pie variables
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* @qdelay: current queue delay
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* @qdelay_old: queue delay in previous qdelay calculation
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* @burst_time: burst time allowance
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* @dq_tstamp: timestamp at which dq rate was last calculated
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* @prob: drop probability
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* @accu_prob: accumulated drop probability
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* @dq_count: number of bytes dequeued in a measurement cycle
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* @avg_dq_rate: calculated average dq rate
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* @qlen_old: queue length during previous qdelay calculation
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* @accu_prob_overflows: number of times accu_prob overflows
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*/
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struct pie_vars {
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psched_time_t qdelay;
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psched_time_t qdelay_old;
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psched_time_t burst_time;
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psched_time_t dq_tstamp;
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u64 prob;
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u64 accu_prob;
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u64 dq_count;
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u32 avg_dq_rate;
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u32 qlen_old;
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u8 accu_prob_overflows;
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};
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/**
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* struct pie_stats - contains pie stats
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* @packets_in: total number of packets enqueued
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* @dropped: packets dropped due to pie action
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* @overlimit: packets dropped due to lack of space in queue
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* @ecn_mark: packets marked with ECN
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* @maxq: maximum queue size
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*/
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struct pie_stats {
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u32 packets_in;
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u32 dropped;
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u32 overlimit;
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u32 ecn_mark;
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u32 maxq;
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};
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/**
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* struct pie_skb_cb - contains private skb vars
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* @enqueue_time: timestamp when the packet is enqueued
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* @mem_usage: size of the skb during enqueue
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*/
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struct pie_skb_cb {
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psched_time_t enqueue_time;
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u32 mem_usage;
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};
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static inline void pie_params_init(struct pie_params *params)
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{
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params->target = PSCHED_NS2TICKS(15 * NSEC_PER_MSEC); /* 15 ms */
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params->tupdate = usecs_to_jiffies(15 * USEC_PER_MSEC); /* 15 ms */
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params->limit = 1000;
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params->alpha = 2;
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params->beta = 20;
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params->ecn = false;
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params->bytemode = false;
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params->dq_rate_estimator = false;
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}
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static inline void pie_vars_init(struct pie_vars *vars)
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{
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vars->burst_time = PSCHED_NS2TICKS(150 * NSEC_PER_MSEC); /* 150 ms */
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vars->dq_tstamp = DTIME_INVALID;
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vars->accu_prob = 0;
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vars->dq_count = DQCOUNT_INVALID;
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vars->avg_dq_rate = 0;
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vars->accu_prob_overflows = 0;
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}
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static inline struct pie_skb_cb *get_pie_cb(const struct sk_buff *skb)
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{
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qdisc_cb_private_validate(skb, sizeof(struct pie_skb_cb));
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return (struct pie_skb_cb *)qdisc_skb_cb(skb)->data;
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}
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static inline psched_time_t pie_get_enqueue_time(const struct sk_buff *skb)
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{
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return get_pie_cb(skb)->enqueue_time;
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}
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static inline void pie_set_enqueue_time(struct sk_buff *skb)
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{
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get_pie_cb(skb)->enqueue_time = psched_get_time();
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}
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bool pie_drop_early(struct Qdisc *sch, struct pie_params *params,
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struct pie_vars *vars, u32 qlen, u32 packet_size);
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void pie_process_dequeue(struct sk_buff *skb, struct pie_params *params,
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struct pie_vars *vars, u32 qlen);
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void pie_calculate_probability(struct pie_params *params, struct pie_vars *vars,
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u32 qlen);
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#endif
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