2 * PIE - Proportional Integral controller Enhanced AQM algorithm.
6 * Copyright (C) 2016 Centre for Advanced Internet Architectures,
7 * Swinburne University of Technology, Melbourne, Australia.
8 * Portions of this code were made possible in part by a gift from
9 * The Comcast Innovation Fund.
10 * Implemented by Rasool Al-Saadi <ralsaadi@swin.edu.au>
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 #ifndef _IP_DN_AQM_PIE_H
35 #define _IP_DN_AQM_PIE_H
38 #define PIE_DQ_THRESHOLD_BITS 14
40 #define PIE_DQ_THRESHOLD (1L << PIE_DQ_THRESHOLD_BITS)
41 #define MEAN_PKTSIZE 800
43 /* 31-bits because random() generates range from 0->(2**31)-1 */
44 #define PIE_PROB_BITS 31
45 #define PIE_MAX_PROB ((1LL<<PIE_PROB_BITS) -1)
47 /* for 16-bits, we have 3-bits for integer part and 13-bits for fraction */
48 #define PIE_FIX_POINT_BITS 13
49 #define PIE_SCALE (1L<<PIE_FIX_POINT_BITS)
55 PIE_CAPDROP_ENABLED = 2,
56 PIE_ON_OFF_MODE_ENABLED = 4,
57 PIE_DEPRATEEST_ENABLED = 8,
58 PIE_DERAND_ENABLED = 16
62 struct dn_aqm_pie_parms {
63 aqm_time_t qdelay_ref; /* AQM Latency Target (default: 15ms) */
64 aqm_time_t tupdate; /* a period to calculate drop probability (default:15ms) */
65 aqm_time_t max_burst; /* AQM Max Burst Allowance (default: 150ms) */
66 uint16_t max_ecnth; /*AQM Max ECN Marking Threshold (default: 10%) */
67 uint16_t alpha; /* (default: 1/8) */
68 uint16_t beta; /* (default: 1+1/4) */
69 uint32_t flags; /* PIE options */
72 /* PIE status variables */
74 struct callout aqm_pie_callout;
75 aqm_time_t burst_allowance;
77 aqm_time_t current_qdelay;
78 aqm_time_t qdelay_old;
80 aqm_time_t measurement_start;
81 aqm_time_t avg_dq_time;
84 struct dn_aqm_pie_parms *parms; /* pointer to PIE configurations */
85 /* pointer to parent queue of FQ-PIE sub-queues, or queue of owner fs. */
88 uint32_t one_third_q_size; /* 1/3 of queue size, for speed optization */
97 /* PIE current state */
100 PIE_INMEASUREMENT = 2
104 * Check if eneque should drop packet to control delay or not based on
106 * return DROP if it is time to drop or ENQUE otherwise.
107 * This function is used by PIE and FQ-PIE.
110 drop_early(struct pie_status *pst, uint32_t qlen)
112 struct dn_aqm_pie_parms *pprms;
116 /* queue is not congested */
118 if ((pst->qdelay_old < (pprms->qdelay_ref >> 1)
119 && pst->drop_prob < PIE_MAX_PROB / 5 )
120 || qlen <= 2 * MEAN_PKTSIZE)
124 if (pst->drop_prob == 0)
127 /* increment accu_prob */
128 if (pprms->flags & PIE_DERAND_ENABLED)
129 pst->accu_prob += pst->drop_prob;
131 /* De-randomize option
132 * if accu_prob < 0.85 -> enqueue
133 * if accu_prob>8.5 ->drop
134 * between 0.85 and 8.5 || !De-randomize --> drop on prob
136 * (0.85 = 17/20 ,8.5 = 17/2)
138 if (pprms->flags & PIE_DERAND_ENABLED) {
139 if(pst->accu_prob < (uint64_t) (PIE_MAX_PROB * 17 / 20))
141 if( pst->accu_prob >= (uint64_t) (PIE_MAX_PROB * 17 / 2))
145 if (random() < pst->drop_prob) {