ceph/src/seastar/dpdk/lib/librte_bitratestats/rte_bitrate.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2017 Intel Corporation
   3  */
   4
   5 #include <rte_common.h>
   6 #include <rte_ethdev.h>
   7 #include <rte_malloc.h>
   8 #include <rte_metrics.h>
   9 #include <rte_bitrate.h>
  10
  11 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  12
  13 /*
  14  * Persistent bit-rate data.
  15  * @internal
  16  */
  17 struct rte_stats_bitrate {
  18         uint64_t last_ibytes;
  19         uint64_t last_obytes;
  20         uint64_t peak_ibits;
  21         uint64_t peak_obits;
  22         uint64_t mean_ibits;
  23         uint64_t mean_obits;
  24         uint64_t ewma_ibits;
  25         uint64_t ewma_obits;
  26 };
  27
  28 struct rte_stats_bitrates {
  29         struct rte_stats_bitrate port_stats[RTE_MAX_ETHPORTS];
  30         uint16_t id_stats_set;
  31 };
  32
  33 struct rte_stats_bitrates *
  34 rte_stats_bitrate_create(void)
  35 {
  36         return rte_zmalloc(NULL, sizeof(struct rte_stats_bitrates),
  37                 RTE_CACHE_LINE_SIZE);
  38 }
  39
  40 int
  41 rte_stats_bitrate_reg(struct rte_stats_bitrates *bitrate_data)
  42 {
  43         const char * const names[] = {
  44                 "ewma_bits_in", "ewma_bits_out",
  45                 "mean_bits_in", "mean_bits_out",
  46                 "peak_bits_in", "peak_bits_out",
  47         };
  48         int return_value;
  49
  50         if (bitrate_data == NULL)
  51                 return -EINVAL;
  52
  53         return_value = rte_metrics_reg_names(&names[0], ARRAY_SIZE(names));
  54         if (return_value >= 0)
  55                 bitrate_data->id_stats_set = return_value;
  56         return return_value;
  57 }
  58
  59 int
  60 rte_stats_bitrate_calc(struct rte_stats_bitrates *bitrate_data,
  61                         uint16_t port_id)
  62 {
  63         struct rte_stats_bitrate *port_data;
  64         struct rte_eth_stats eth_stats;
  65         int ret_code;
  66         uint64_t cnt_bits;
  67         int64_t delta;
  68         const int64_t alpha_percent = 20;
  69         uint64_t values[6];
  70         int ret;
  71
  72         if (bitrate_data == NULL)
  73                 return -EINVAL;
  74
  75         ret_code = rte_eth_stats_get(port_id, &eth_stats);
  76         if (ret_code != 0)
  77                 return ret_code;
  78
  79         port_data = &bitrate_data->port_stats[port_id];
  80
  81         /* Incoming bitrate. This is an iteratively calculated EWMA
  82          * (Exponentially Weighted Moving Average) that uses a
  83          * weighting factor of alpha_percent. An unsmoothed mean
  84          * for just the current time delta is also calculated for the
  85          * benefit of people who don't understand signal processing.
  86          */
  87         cnt_bits = (eth_stats.ibytes - port_data->last_ibytes) << 3;
  88         port_data->last_ibytes = eth_stats.ibytes;
  89         if (cnt_bits > port_data->peak_ibits)
  90                 port_data->peak_ibits = cnt_bits;
  91         delta = cnt_bits;
  92         delta -= port_data->ewma_ibits;
  93         /* The +-50 fixes integer rounding during division */
  94         if (delta > 0)
  95                 delta = (delta * alpha_percent + 50) / 100;
  96         else
  97                 delta = (delta * alpha_percent - 50) / 100;
  98         port_data->ewma_ibits += delta;
  99         /* Integer roundoff prevents EWMA between 0 and (100/alpha_percent)
 100          * ever reaching zero in no-traffic conditions
 101          */
 102         if (cnt_bits == 0 && delta == 0)
 103                 port_data->ewma_ibits = 0;
 104         port_data->mean_ibits = cnt_bits;
 105
 106         /* Outgoing bitrate (also EWMA) */
 107         cnt_bits = (eth_stats.obytes - port_data->last_obytes) << 3;
 108         port_data->last_obytes = eth_stats.obytes;
 109         if (cnt_bits > port_data->peak_obits)
 110                 port_data->peak_obits = cnt_bits;
 111         delta = cnt_bits;
 112         delta -= port_data->ewma_obits;
 113         if (delta > 0)
 114                 delta = (delta * alpha_percent + 50) / 100;
 115         else
 116                 delta = (delta * alpha_percent - 50) / 100;
 117         port_data->ewma_obits += delta;
 118         if (cnt_bits == 0 && delta == 0)
 119                 port_data->ewma_obits = 0;
 120         port_data->mean_obits = cnt_bits;
 121
 122         values[0] = port_data->ewma_ibits;
 123         values[1] = port_data->ewma_obits;
 124         values[2] = port_data->mean_ibits;
 125         values[3] = port_data->mean_obits;
 126         values[4] = port_data->peak_ibits;
 127         values[5] = port_data->peak_obits;
 128         ret = rte_metrics_update_values(port_id, bitrate_data->id_stats_set,
 129                 values, ARRAY_SIZE(values));
 130         if (ret < 0)
 131                 return ret;
 132
 133         return 0;
 134 }