lib/dim/net_dim.c

   1 // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
   2 /*
   3  * Copyright (c) 2018, Mellanox Technologies inc.  All rights reserved.
   4  */
   5
   6 #include <linux/dim.h>
   7
   8 struct dim_cq_moder
   9 net_dim_get_rx_moderation(u8 cq_period_mode, int ix)
  10 {
  11         struct dim_cq_moder cq_moder = rx_profile[cq_period_mode][ix];
  12
  13         cq_moder.cq_period_mode = cq_period_mode;
  14         return cq_moder;
  15 }
  16 EXPORT_SYMBOL(net_dim_get_rx_moderation);
  17
  18 struct dim_cq_moder
  19 net_dim_get_def_rx_moderation(u8 cq_period_mode)
  20 {
  21         u8 profile_ix = cq_period_mode == DIM_CQ_PERIOD_MODE_START_FROM_CQE ?
  22                         NET_DIM_DEF_PROFILE_CQE : NET_DIM_DEF_PROFILE_EQE;
  23
  24         return net_dim_get_rx_moderation(cq_period_mode, profile_ix);
  25 }
  26 EXPORT_SYMBOL(net_dim_get_def_rx_moderation);
  27
  28 struct dim_cq_moder
  29 net_dim_get_tx_moderation(u8 cq_period_mode, int ix)
  30 {
  31         struct dim_cq_moder cq_moder = tx_profile[cq_period_mode][ix];
  32
  33         cq_moder.cq_period_mode = cq_period_mode;
  34         return cq_moder;
  35 }
  36 EXPORT_SYMBOL(net_dim_get_tx_moderation);
  37
  38 struct dim_cq_moder
  39 net_dim_get_def_tx_moderation(u8 cq_period_mode)
  40 {
  41         u8 profile_ix = cq_period_mode == DIM_CQ_PERIOD_MODE_START_FROM_CQE ?
  42                         NET_DIM_DEF_PROFILE_CQE : NET_DIM_DEF_PROFILE_EQE;
  43
  44         return net_dim_get_tx_moderation(cq_period_mode, profile_ix);
  45 }
  46 EXPORT_SYMBOL(net_dim_get_def_tx_moderation);
  47
  48 static int net_dim_step(struct dim *dim)
  49 {
  50         if (dim->tired == (NET_DIM_PARAMS_NUM_PROFILES * 2))
  51                 return DIM_TOO_TIRED;
  52
  53         switch (dim->tune_state) {
  54         case DIM_PARKING_ON_TOP:
  55         case DIM_PARKING_TIRED:
  56                 break;
  57         case DIM_GOING_RIGHT:
  58                 if (dim->profile_ix == (NET_DIM_PARAMS_NUM_PROFILES - 1))
  59                         return DIM_ON_EDGE;
  60                 dim->profile_ix++;
  61                 dim->steps_right++;
  62                 break;
  63         case DIM_GOING_LEFT:
  64                 if (dim->profile_ix == 0)
  65                         return DIM_ON_EDGE;
  66                 dim->profile_ix--;
  67                 dim->steps_left++;
  68                 break;
  69         }
  70
  71         dim->tired++;
  72         return DIM_STEPPED;
  73 }
  74
  75 static void net_dim_exit_parking(struct dim *dim)
  76 {
  77         dim->tune_state = dim->profile_ix ? DIM_GOING_LEFT : DIM_GOING_RIGHT;
  78         net_dim_step(dim);
  79 }
  80
  81 static int net_dim_stats_compare(struct dim_stats *curr,
  82                                  struct dim_stats *prev)
  83 {
  84         if (!prev->bpms)
  85                 return curr->bpms ? DIM_STATS_BETTER : DIM_STATS_SAME;
  86
  87         if (IS_SIGNIFICANT_DIFF(curr->bpms, prev->bpms))
  88                 return (curr->bpms > prev->bpms) ? DIM_STATS_BETTER :
  89                                                    DIM_STATS_WORSE;
  90
  91         if (!prev->ppms)
  92                 return curr->ppms ? DIM_STATS_BETTER :
  93                                     DIM_STATS_SAME;
  94
  95         if (IS_SIGNIFICANT_DIFF(curr->ppms, prev->ppms))
  96                 return (curr->ppms > prev->ppms) ? DIM_STATS_BETTER :
  97                                                    DIM_STATS_WORSE;
  98
  99         if (!prev->epms)
 100                 return DIM_STATS_SAME;
 101
 102         if (IS_SIGNIFICANT_DIFF(curr->epms, prev->epms))
 103                 return (curr->epms < prev->epms) ? DIM_STATS_BETTER :
 104                                                    DIM_STATS_WORSE;
 105
 106         return DIM_STATS_SAME;
 107 }
 108
 109 static bool net_dim_decision(struct dim_stats *curr_stats, struct dim *dim)
 110 {
 111         int prev_state = dim->tune_state;
 112         int prev_ix = dim->profile_ix;
 113         int stats_res;
 114         int step_res;
 115
 116         switch (dim->tune_state) {
 117         case DIM_PARKING_ON_TOP:
 118                 stats_res = net_dim_stats_compare(curr_stats,
 119                                                   &dim->prev_stats);
 120                 if (stats_res != DIM_STATS_SAME)
 121                         net_dim_exit_parking(dim);
 122                 break;
 123
 124         case DIM_PARKING_TIRED:
 125                 dim->tired--;
 126                 if (!dim->tired)
 127                         net_dim_exit_parking(dim);
 128                 break;
 129
 130         case DIM_GOING_RIGHT:
 131         case DIM_GOING_LEFT:
 132                 stats_res = net_dim_stats_compare(curr_stats,
 133                                                   &dim->prev_stats);
 134                 if (stats_res != DIM_STATS_BETTER)
 135                         dim_turn(dim);
 136
 137                 if (dim_on_top(dim)) {
 138                         dim_park_on_top(dim);
 139                         break;
 140                 }
 141
 142                 step_res = net_dim_step(dim);
 143                 switch (step_res) {
 144                 case DIM_ON_EDGE:
 145                         dim_park_on_top(dim);
 146                         break;
 147                 case DIM_TOO_TIRED:
 148                         dim_park_tired(dim);
 149                         break;
 150                 }
 151
 152                 break;
 153         }
 154
 155         if (prev_state != DIM_PARKING_ON_TOP ||
 156             dim->tune_state != DIM_PARKING_ON_TOP)
 157                 dim->prev_stats = *curr_stats;
 158
 159         return dim->profile_ix != prev_ix;
 160 }
 161
 162 void net_dim(struct dim *dim, struct dim_sample end_sample)
 163 {
 164         struct dim_stats curr_stats;
 165         u16 nevents;
 166
 167         switch (dim->state) {
 168         case DIM_MEASURE_IN_PROGRESS:
 169                 nevents = BIT_GAP(BITS_PER_TYPE(u16),
 170                                   end_sample.event_ctr,
 171                                   dim->start_sample.event_ctr);
 172                 if (nevents < DIM_NEVENTS)
 173                         break;
 174                 dim_calc_stats(&dim->start_sample, &end_sample, &curr_stats);
 175                 if (net_dim_decision(&curr_stats, dim)) {
 176                         dim->state = DIM_APPLY_NEW_PROFILE;
 177                         schedule_work(&dim->work);
 178                         break;
 179                 }
 180                 /* fall through */
 181         case DIM_START_MEASURE:
 182                 dim_update_sample(end_sample.event_ctr, end_sample.pkt_ctr,
 183                                   end_sample.byte_ctr, &dim->start_sample);
 184                 dim->state = DIM_MEASURE_IN_PROGRESS;
 185                 break;
 186         case DIM_APPLY_NEW_PROFILE:
 187                 break;
 188         }
 189 }
 190 EXPORT_SYMBOL(net_dim);