1 /* 2 * PIE - Proportional Integral controller Enhanced AQM algorithm. 3 * 4 * Copyright (C) 2016 Centre for Advanced Internet Architectures, 5 * Swinburne University of Technology, Melbourne, Australia. 6 * Portions of this code were made possible in part by a gift from 7 * The Comcast Innovation Fund. 8 * Implemented by Rasool Al-Saadi <ralsaadi@swin.edu.au> 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #ifndef _IP_DN_AQM_PIE_H 33 #define _IP_DN_AQM_PIE_H 34 35 #define DN_AQM_PIE 2 36 #define PIE_DQ_THRESHOLD_BITS 14 37 /* 2^14 =16KB */ 38 #define PIE_DQ_THRESHOLD (1L << PIE_DQ_THRESHOLD_BITS) 39 #define MEAN_PKTSIZE 800 40 41 /* 31-bits because random() generates range from 0->(2**31)-1 */ 42 #define PIE_PROB_BITS 31 43 #define PIE_MAX_PROB ((1LL<<PIE_PROB_BITS) -1) 44 45 /* for 16-bits, we have 3-bits for integer part and 13-bits for fraction */ 46 #define PIE_FIX_POINT_BITS 13 47 #define PIE_SCALE (1L<<PIE_FIX_POINT_BITS) 48 49 /* PIE options */ 50 enum { 51 PIE_ECN_ENABLED =1, 52 PIE_CAPDROP_ENABLED = 2, 53 PIE_ON_OFF_MODE_ENABLED = 4, 54 PIE_DEPRATEEST_ENABLED = 8, 55 PIE_DERAND_ENABLED = 16 56 }; 57 58 /* PIE parameters */ 59 struct dn_aqm_pie_parms { 60 aqm_time_t qdelay_ref; /* AQM Latency Target (default: 15ms) */ 61 aqm_time_t tupdate; /* a period to calculate drop probability (default:15ms) */ 62 aqm_time_t max_burst; /* AQM Max Burst Allowance (default: 150ms) */ 63 uint16_t max_ecnth; /*AQM Max ECN Marking Threshold (default: 10%) */ 64 uint16_t alpha; /* (default: 1/8) */ 65 uint16_t beta; /* (default: 1+1/4) */ 66 uint32_t flags; /* PIE options */ 67 }; 68 69 /* PIE status variables */ 70 struct pie_status{ 71 struct callout aqm_pie_callout; 72 aqm_time_t burst_allowance; 73 uint32_t drop_prob; 74 aqm_time_t current_qdelay; 75 aqm_time_t qdelay_old; 76 uint64_t accu_prob; 77 aqm_time_t measurement_start; 78 aqm_time_t avg_dq_time; 79 uint32_t dq_count; 80 uint32_t sflags; 81 struct dn_aqm_pie_parms *parms; /* pointer to PIE configurations */ 82 /* pointer to parent queue of FQ-PIE sub-queues, or queue of owner fs. */ 83 struct dn_queue *pq; 84 struct mtx lock_mtx; 85 uint32_t one_third_q_size; /* 1/3 of queue size, for speed optization */ 86 }; 87 88 enum { 89 ENQUE = 1, 90 DROP, 91 MARKECN 92 }; 93 94 /* PIE current state */ 95 enum { 96 PIE_ACTIVE = 1, 97 PIE_INMEASUREMENT = 2 98 }; 99 100 /* 101 * Check if eneque should drop packet to control delay or not based on 102 * PIe algorithm. 103 * return DROP if it is time to drop or ENQUE otherwise. 104 * This function is used by PIE and FQ-PIE. 105 */ 106 __inline static int 107 drop_early(struct pie_status *pst, uint32_t qlen) 108 { 109 struct dn_aqm_pie_parms *pprms; 110 111 pprms = pst->parms; 112 113 /* queue is not congested */ 114 115 if ((pst->qdelay_old < (pprms->qdelay_ref >> 1) 116 && pst->drop_prob < PIE_MAX_PROB / 5 ) 117 || qlen <= 2 * MEAN_PKTSIZE) 118 return ENQUE; 119 120 if (pst->drop_prob == 0) 121 pst->accu_prob = 0; 122 123 /* increment accu_prob */ 124 if (pprms->flags & PIE_DERAND_ENABLED) 125 pst->accu_prob += pst->drop_prob; 126 127 /* De-randomize option 128 * if accu_prob < 0.85 -> enqueue 129 * if accu_prob>8.5 ->drop 130 * between 0.85 and 8.5 || !De-randomize --> drop on prob 131 * 132 * (0.85 = 17/20 ,8.5 = 17/2) 133 */ 134 if (pprms->flags & PIE_DERAND_ENABLED) { 135 if(pst->accu_prob < (uint64_t) (PIE_MAX_PROB * 17 / 20)) 136 return ENQUE; 137 if( pst->accu_prob >= (uint64_t) (PIE_MAX_PROB * 17 / 2)) 138 return DROP; 139 } 140 141 if (random() < pst->drop_prob) { 142 pst->accu_prob = 0; 143 return DROP; 144 } 145 146 return ENQUE; 147 } 148 149 #endif 150