net_dim.h

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0
    3  *
    4  * Copyright (c) 2016, Mellanox Technologies. All rights reserved.
    5  * Copyright (c) 2017-2018, Broadcom Limited. All rights reserved.
    6  *
    7  * This software is available to you under a choice of one of two
    8  * licenses.  You may choose to be licensed under the terms of the GNU
    9  * General Public License (GPL) Version 2, available from the file
   10  * COPYING in the main directory of this source tree, or the
   11  * OpenIB.org BSD license below:
   12  *
   13  *     Redistribution and use in source and binary forms, with or
   14  *     without modification, are permitted provided that the following
   15  *     conditions are met:
   16  *
   17  *      - Redistributions of source code must retain the above
   18  *        copyright notice, this list of conditions and the following
   19  *        disclaimer.
   20  *
   21  *      - Redistributions in binary form must reproduce the above
   22  *        copyright notice, this list of conditions and the following
   23  *        disclaimer in the documentation and/or other materials
   24  *        provided with the distribution.
   25  *
   26  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   27  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   28  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   29  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   30  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   31  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   32  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   33  * SOFTWARE.
   34  *
   35  * $FreeBSD$
   36  */
   37 
   38 /* This file implements Dynamic Interrupt Moderation, DIM */
   39 
   40 #ifndef _LINUXKPI_LINUX_NET_DIM_H
   41 #define _LINUXKPI_LINUX_NET_DIM_H
   42 
   43 #include <asm/types.h>
   44 
   45 #include <linux/workqueue.h>
   46 #include <linux/ktime.h>
   47 
   48 struct net_dim_cq_moder {
   49         u16     usec;
   50         u16     pkts;
   51         u8      cq_period_mode;
   52 };
   53 
   54 struct net_dim_sample {
   55         ktime_t time;
   56         u32     pkt_ctr;
   57         u32     byte_ctr;
   58         u16     event_ctr;
   59 };
   60 
   61 struct net_dim_stats {
   62         int     ppms;                   /* packets per msec */
   63         int     bpms;                   /* bytes per msec */
   64         int     epms;                   /* events per msec */
   65 };
   66 
   67 struct net_dim {                        /* Adaptive Moderation */
   68         u8      state;
   69         struct net_dim_stats prev_stats;
   70         struct net_dim_sample start_sample;
   71         struct work_struct work;
   72         u16     event_ctr;
   73         u8      profile_ix;
   74         u8      mode;
   75         u8      tune_state;
   76         u8      steps_right;
   77         u8      steps_left;
   78         u8      tired;
   79 };
   80 
   81 enum {
   82         NET_DIM_CQ_PERIOD_MODE_START_FROM_EQE = 0x0,
   83         NET_DIM_CQ_PERIOD_MODE_START_FROM_CQE = 0x1,
   84         NET_DIM_CQ_PERIOD_NUM_MODES = 0x2,
   85         NET_DIM_CQ_PERIOD_MODE_DISABLED = 0xFF,
   86 };
   87 
   88 /* Adaptive moderation logic */
   89 enum {
   90         NET_DIM_START_MEASURE,
   91         NET_DIM_MEASURE_IN_PROGRESS,
   92         NET_DIM_APPLY_NEW_PROFILE,
   93 };
   94 
   95 enum {
   96         NET_DIM_PARKING_ON_TOP,
   97         NET_DIM_PARKING_TIRED,
   98         NET_DIM_GOING_RIGHT,
   99         NET_DIM_GOING_LEFT,
  100 };
  101 
  102 enum {
  103         NET_DIM_STATS_WORSE,
  104         NET_DIM_STATS_SAME,
  105         NET_DIM_STATS_BETTER,
  106 };
  107 
  108 enum {
  109         NET_DIM_STEPPED,
  110         NET_DIM_TOO_TIRED,
  111         NET_DIM_ON_EDGE,
  112 };
  113 
  114 #define NET_DIM_PARAMS_NUM_PROFILES 5
  115 /* Adaptive moderation profiles */
  116 #define NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE 256
  117 #define NET_DIM_DEF_PROFILE_CQE 1
  118 #define NET_DIM_DEF_PROFILE_EQE 1
  119 
  120 /* All profiles sizes must be NET_PARAMS_DIM_NUM_PROFILES */
  121 #define NET_DIM_EQE_PROFILES { \
  122         {1,   NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
  123         {8,   NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
  124         {64,  NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
  125         {128, NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
  126         {256, NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
  127 }
  128 
  129 #define NET_DIM_CQE_PROFILES { \
  130         {2,  256},             \
  131         {8,  128},             \
  132         {16, 64},              \
  133         {32, 64},              \
  134         {64, 64}               \
  135 }
  136 
  137 static const struct net_dim_cq_moder
  138         net_dim_profile[NET_DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
  139         NET_DIM_EQE_PROFILES,
  140         NET_DIM_CQE_PROFILES,
  141 };
  142 
  143 static inline struct net_dim_cq_moder
  144 net_dim_get_profile(u8 cq_period_mode,
  145     int ix)
  146 {
  147         struct net_dim_cq_moder cq_moder;
  148 
  149         cq_moder = net_dim_profile[cq_period_mode][ix];
  150         cq_moder.cq_period_mode = cq_period_mode;
  151         return cq_moder;
  152 }
  153 
  154 static inline struct net_dim_cq_moder
  155 net_dim_get_def_profile(u8 rx_cq_period_mode)
  156 {
  157         int default_profile_ix;
  158 
  159         if (rx_cq_period_mode == NET_DIM_CQ_PERIOD_MODE_START_FROM_CQE)
  160                 default_profile_ix = NET_DIM_DEF_PROFILE_CQE;
  161         else    /* NET_DIM_CQ_PERIOD_MODE_START_FROM_EQE */
  162                 default_profile_ix = NET_DIM_DEF_PROFILE_EQE;
  163 
  164         return net_dim_get_profile(rx_cq_period_mode, default_profile_ix);
  165 }
  166 
  167 static inline bool
  168 net_dim_on_top(struct net_dim *dim)
  169 {
  170         switch (dim->tune_state) {
  171         case NET_DIM_PARKING_ON_TOP:
  172         case NET_DIM_PARKING_TIRED:
  173                 return true;
  174         case NET_DIM_GOING_RIGHT:
  175                 return (dim->steps_left > 1) && (dim->steps_right == 1);
  176         default:        /* NET_DIM_GOING_LEFT */
  177                 return (dim->steps_right > 1) && (dim->steps_left == 1);
  178         }
  179 }
  180 
  181 static inline void
  182 net_dim_turn(struct net_dim *dim)
  183 {
  184         switch (dim->tune_state) {
  185         case NET_DIM_PARKING_ON_TOP:
  186         case NET_DIM_PARKING_TIRED:
  187                 break;
  188         case NET_DIM_GOING_RIGHT:
  189                 dim->tune_state = NET_DIM_GOING_LEFT;
  190                 dim->steps_left = 0;
  191                 break;
  192         case NET_DIM_GOING_LEFT:
  193                 dim->tune_state = NET_DIM_GOING_RIGHT;
  194                 dim->steps_right = 0;
  195                 break;
  196         }
  197 }
  198 
  199 static inline int
  200 net_dim_step(struct net_dim *dim)
  201 {
  202         if (dim->tired == (NET_DIM_PARAMS_NUM_PROFILES * 2))
  203                 return NET_DIM_TOO_TIRED;
  204 
  205         switch (dim->tune_state) {
  206         case NET_DIM_PARKING_ON_TOP:
  207         case NET_DIM_PARKING_TIRED:
  208                 break;
  209         case NET_DIM_GOING_RIGHT:
  210                 if (dim->profile_ix == (NET_DIM_PARAMS_NUM_PROFILES - 1))
  211                         return NET_DIM_ON_EDGE;
  212                 dim->profile_ix++;
  213                 dim->steps_right++;
  214                 break;
  215         case NET_DIM_GOING_LEFT:
  216                 if (dim->profile_ix == 0)
  217                         return NET_DIM_ON_EDGE;
  218                 dim->profile_ix--;
  219                 dim->steps_left++;
  220                 break;
  221         }
  222 
  223         dim->tired++;
  224         return NET_DIM_STEPPED;
  225 }
  226 
  227 static inline void
  228 net_dim_park_on_top(struct net_dim *dim)
  229 {
  230         dim->steps_right = 0;
  231         dim->steps_left = 0;
  232         dim->tired = 0;
  233         dim->tune_state = NET_DIM_PARKING_ON_TOP;
  234 }
  235 
  236 static inline void
  237 net_dim_park_tired(struct net_dim *dim)
  238 {
  239         dim->steps_right = 0;
  240         dim->steps_left = 0;
  241         dim->tune_state = NET_DIM_PARKING_TIRED;
  242 }
  243 
  244 static inline void
  245 net_dim_exit_parking(struct net_dim *dim)
  246 {
  247         dim->tune_state = dim->profile_ix ? NET_DIM_GOING_LEFT :
  248         NET_DIM_GOING_RIGHT;
  249         net_dim_step(dim);
  250 }
  251 
  252 #define IS_SIGNIFICANT_DIFF(val, ref) \
  253         (((100UL * abs((val) - (ref))) / (ref)) > 10)   /* more than 10%
  254                                                          * difference */
  255 
  256 static inline int
  257 net_dim_stats_compare(struct net_dim_stats *curr,
  258     struct net_dim_stats *prev)
  259 {
  260         if (!prev->bpms)
  261                 return curr->bpms ? NET_DIM_STATS_BETTER :
  262                 NET_DIM_STATS_SAME;
  263 
  264         if (IS_SIGNIFICANT_DIFF(curr->bpms, prev->bpms))
  265                 return (curr->bpms > prev->bpms) ? NET_DIM_STATS_BETTER :
  266                     NET_DIM_STATS_WORSE;
  267 
  268         if (!prev->ppms)
  269                 return curr->ppms ? NET_DIM_STATS_BETTER :
  270                     NET_DIM_STATS_SAME;
  271 
  272         if (IS_SIGNIFICANT_DIFF(curr->ppms, prev->ppms))
  273                 return (curr->ppms > prev->ppms) ? NET_DIM_STATS_BETTER :
  274                     NET_DIM_STATS_WORSE;
  275 
  276         if (!prev->epms)
  277                 return NET_DIM_STATS_SAME;
  278 
  279         if (IS_SIGNIFICANT_DIFF(curr->epms, prev->epms))
  280                 return (curr->epms < prev->epms) ? NET_DIM_STATS_BETTER :
  281                     NET_DIM_STATS_WORSE;
  282 
  283         return NET_DIM_STATS_SAME;
  284 }
  285 
  286 static inline bool
  287 net_dim_decision(struct net_dim_stats *curr_stats,
  288     struct net_dim *dim)
  289 {
  290         int prev_state = dim->tune_state;
  291         int prev_ix = dim->profile_ix;
  292         int stats_res;
  293         int step_res;
  294 
  295         switch (dim->tune_state) {
  296         case NET_DIM_PARKING_ON_TOP:
  297                 stats_res = net_dim_stats_compare(curr_stats, &dim->prev_stats);
  298                 if (stats_res != NET_DIM_STATS_SAME)
  299                         net_dim_exit_parking(dim);
  300                 break;
  301 
  302         case NET_DIM_PARKING_TIRED:
  303                 dim->tired--;
  304                 if (!dim->tired)
  305                         net_dim_exit_parking(dim);
  306                 break;
  307 
  308         case NET_DIM_GOING_RIGHT:
  309         case NET_DIM_GOING_LEFT:
  310                 stats_res = net_dim_stats_compare(curr_stats, &dim->prev_stats);
  311                 if (stats_res != NET_DIM_STATS_BETTER)
  312                         net_dim_turn(dim);
  313 
  314                 if (net_dim_on_top(dim)) {
  315                         net_dim_park_on_top(dim);
  316                         break;
  317                 }
  318                 step_res = net_dim_step(dim);
  319                 switch (step_res) {
  320                 case NET_DIM_ON_EDGE:
  321                         net_dim_park_on_top(dim);
  322                         break;
  323                 case NET_DIM_TOO_TIRED:
  324                         net_dim_park_tired(dim);
  325                         break;
  326                 }
  327 
  328                 break;
  329         }
  330 
  331         if ((prev_state != NET_DIM_PARKING_ON_TOP) ||
  332             (dim->tune_state != NET_DIM_PARKING_ON_TOP))
  333                 dim->prev_stats = *curr_stats;
  334 
  335         return dim->profile_ix != prev_ix;
  336 }
  337 
  338 static inline void
  339 net_dim_sample(u16 event_ctr,
  340     u64 packets,
  341     u64 bytes,
  342     struct net_dim_sample *s)
  343 {
  344         s->time = ktime_get();
  345         s->pkt_ctr = packets;
  346         s->byte_ctr = bytes;
  347         s->event_ctr = event_ctr;
  348 }
  349 
  350 #define NET_DIM_NEVENTS 64
  351 #define BIT_GAP(bits, end, start) ((((end) - (start)) + BIT_ULL(bits)) & (BIT_ULL(bits) - 1))
  352 
  353 static inline void
  354 net_dim_calc_stats(struct net_dim_sample *start,
  355     struct net_dim_sample *end,
  356     struct net_dim_stats *curr_stats)
  357 {
  358         /* u32 holds up to 71 minutes, should be enough */
  359         u32 delta_us = ktime_us_delta(end->time, start->time);
  360         u32 npkts = BIT_GAP(BITS_PER_TYPE(u32), end->pkt_ctr, start->pkt_ctr);
  361         u32 nbytes = BIT_GAP(BITS_PER_TYPE(u32), end->byte_ctr,
  362             start->byte_ctr);
  363 
  364         if (!delta_us)
  365                 return;
  366 
  367         curr_stats->ppms = DIV_ROUND_UP(npkts * USEC_PER_MSEC, delta_us);
  368         curr_stats->bpms = DIV_ROUND_UP(nbytes * USEC_PER_MSEC, delta_us);
  369         curr_stats->epms = DIV_ROUND_UP(NET_DIM_NEVENTS * USEC_PER_MSEC,
  370             delta_us);
  371 }
  372 
  373 static inline void
  374 net_dim(struct net_dim *dim,
  375     u64 packets, u64 bytes)
  376 {
  377         struct net_dim_stats curr_stats;
  378         struct net_dim_sample end_sample;
  379         u16 nevents;
  380 
  381         dim->event_ctr++;
  382 
  383         switch (dim->state) {
  384         case NET_DIM_MEASURE_IN_PROGRESS:
  385                 nevents = BIT_GAP(BITS_PER_TYPE(u16),
  386                     dim->event_ctr,
  387                     dim->start_sample.event_ctr);
  388                 if (nevents < NET_DIM_NEVENTS)
  389                         break;
  390                 net_dim_sample(dim->event_ctr, packets, bytes, &end_sample);
  391                 net_dim_calc_stats(&dim->start_sample, &end_sample,
  392                     &curr_stats);
  393                 if (net_dim_decision(&curr_stats, dim)) {
  394                         dim->state = NET_DIM_APPLY_NEW_PROFILE;
  395                         schedule_work(&dim->work);
  396                         break;
  397                 }
  398                 /* FALLTHROUGH */
  399         case NET_DIM_START_MEASURE:
  400                 net_dim_sample(dim->event_ctr, packets, bytes, &dim->start_sample);
  401                 dim->state = NET_DIM_MEASURE_IN_PROGRESS;
  402                 break;
  403         case NET_DIM_APPLY_NEW_PROFILE:
  404                 break;
  405         default:
  406                 break;
  407         }
  408 }
  409 
  410 #endif                                  /* _LINUXKPI_LINUX_NET_DIM_H */
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FreeBSD/Linux Kernel Cross Reference sys/compat/linuxkpi/common/include/linux/net_dim.h

FreeBSD/Linux Kernel Cross Reference
sys/compat/linuxkpi/common/include/linux/net_dim.h
