lib/stress.c

   1 /*
   2  * Copyright (c) 2010, 2011 Nicira, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <config.h>
  18 #include "stress.h"
  19 #include <stdlib.h>
  20 #include <string.h>
  21 #include "unixctl.h"
  22 #include "dynamic-string.h"
  23 #include "random.h"
  24 #include "util.h"
  25 #include "vlog.h"
  26
  27 VLOG_DEFINE_THIS_MODULE(stress);
  28
  29 /* The stress options. */
  30 #if USE_LINKER_SECTIONS
  31 extern struct stress_option *__start_stress_options[];
  32 extern struct stress_option *__stop_stress_options[];
  33 #define stress_options __start_stress_options
  34 #define n_stress_options (__stop_stress_options - __start_stress_options)
  35 #else  /* !USE_LINKER_SECTIONS */
  36 #undef STRESS_OPTION
  37 #define STRESS_OPTION(NAME, DESCRIPTION, RECOMMENDED, MIN, MAX, DEFAULT) \
  38         STRESS_OPTION__(NAME, DESCRIPTION, RECOMMENDED, MIN, MAX, DEFAULT);
  39 #include "stress.def"
  40 #undef STRESS_OPTION
  41
  42 struct stress_option *stress_options[] = {
  43 #define STRESS_OPTION(NAME, DESCRIPTION, RECOMMENDED, MIN, MAX, DEFAULT) \
  44         &stress_##NAME,
  45 #include "stress.def"
  46 #undef STRESS_OPTION
  47 };
  48 #define n_stress_options ARRAY_SIZE(stress_options)
  49 #endif  /* !USE_LINKER_SECTIONS */
  50
  51 /* Enable stress options? */
  52 static bool stress_enabled;
  53 \f
  54 static void
  55 stress_reset(struct stress_option *option)
  56 {
  57     if (!option->period || !stress_enabled) {
  58         option->counter = UINT_MAX;
  59     } else if (!option->random) {
  60         option->counter = option->period;
  61     } else if (option->period < UINT32_MAX / 2) {
  62         /* Random distribution with mean of option->period. */
  63         option->counter = random_uint32() % ((2 * option->period) - 1) + 1;
  64     } else {
  65         option->counter = random_uint32();
  66     }
  67 }
  68
  69 static void
  70 stress_enable(bool enable)
  71 {
  72     if (stress_enabled != enable) {
  73         int i;
  74
  75         stress_enabled = enable;
  76         for (i = 0; i < n_stress_options; i++) {
  77             stress_reset(stress_options[i]);
  78         }
  79     }
  80 }
  81
  82 bool
  83 stress_sample_slowpath__(struct stress_option *option)
  84 {
  85     stress_reset(option);
  86     if (option->period && stress_enabled) {
  87         static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 1);
  88
  89         option->hits++;
  90         VLOG_DBG_RL(&rl, "%s hit (%llu total)", option->name, option->hits);
  91
  92         return true;
  93     } else {
  94         return false;
  95     }
  96 }
  97
  98 static void
  99 stress_set(struct stress_option *option, unsigned int period, bool random)
 100 {
 101     if (period > option->max) {
 102         period = option->max;
 103     }
 104     if (period < option->min) {
 105         period = option->min;
 106     }
 107     if (period != option->period || random != option->random) {
 108         option->random = random;
 109         option->period = period;
 110         stress_reset(option);
 111     }
 112 }
 113 \f
 114 static void
 115 stress_unixctl_list(struct unixctl_conn *conn, int argc OVS_UNUSED,
 116                     const char *argv[] OVS_UNUSED, void *aux OVS_UNUSED)
 117 {
 118     int i, found = 0;
 119     struct ds results;
 120
 121     ds_init(&results);
 122     ds_put_cstr(&results, "NAME (DESCRIPTION)\n");
 123     ds_put_format(&results, "%11s %10s %10s %10s\n",
 124                   "PERIOD", "MODE", "COUNTER", "HITS");
 125     ds_put_format(&results, "%11s %10s %10s %10s\n",
 126                   "RECOMMENDED", "MINIMUM", "MAXIMUM", "DEFAULT");
 127     for (i = 0; i < n_stress_options; i++) {
 128         struct stress_option *option = stress_options[i];
 129         if (!argv[1] || strstr(option->name, argv[1])) {
 130             ds_put_format(&results, "\n%s (%s)\n",
 131                           option->name, option->description);
 132             if (option->period) {
 133                 ds_put_format(&results, "%11u %10s ", option->period,
 134                               option->random ? "random" : "periodic");
 135                 if (stress_enabled) {
 136                     ds_put_format(&results, "%10u", option->counter);
 137                 } else {
 138                     ds_put_cstr(&results, "     n/a");
 139                 }
 140             } else {
 141                 ds_put_format(&results, "%11s %10s %10s",
 142                               "disabled", "n/a", "n/a");
 143             }
 144             ds_put_format(&results, " %10llu\n", option->hits);
 145             ds_put_format(&results, "%11u %10u %10u ",
 146                           option->recommended, option->min, option->max);
 147             if (!option->def) {
 148                 ds_put_format(&results, "%10s", "disabled");
 149             } else {
 150                 ds_put_format(&results, "%10u", option->def);
 151             }
 152             ds_put_char(&results, '\n');
 153             found++;
 154         }
 155     }
 156     if (found) {
 157         unixctl_command_reply(conn, ds_cstr(&results));
 158     } else {
 159         unixctl_command_reply_error(conn, NULL);
 160     }
 161     ds_destroy(&results);
 162 }
 163
 164 static void
 165 stress_unixctl_enable(struct unixctl_conn *conn, int argc OVS_UNUSED,
 166                       const char *argv[] OVS_UNUSED, void *aux OVS_UNUSED)
 167 {
 168     stress_enable(true);
 169     unixctl_command_reply(conn, NULL);
 170 }
 171
 172 static void
 173 stress_unixctl_disable(struct unixctl_conn *conn, int argc OVS_UNUSED,
 174                        const char *argv[] OVS_UNUSED, void *aux OVS_UNUSED)
 175 {
 176     stress_enable(false);
 177     unixctl_command_reply(conn, NULL);
 178 }
 179
 180 static void
 181 stress_unixctl_set(struct unixctl_conn *conn, int argc OVS_UNUSED,
 182                    const char *argv[], void *aux OVS_UNUSED)
 183 {
 184     const char *option_name = argv[1];
 185     const char *option_val = argv[2];
 186     int i;
 187
 188     for (i = 0; i < n_stress_options; i++) {
 189         struct stress_option *option = stress_options[i];
 190         if (!strcmp(option_name, option->name)) {
 191             unsigned int period = strtoul(option_val, NULL, 0);
 192             bool random = !strcmp(argv[3], "random");
 193
 194             stress_set(option, period, random);
 195             unixctl_command_reply(conn, NULL);
 196             return;
 197         }
 198     }
 199
 200     unixctl_command_reply_error(conn, NULL);
 201 }
 202
 203 /* Exposes ovs-appctl access to the stress options.
 204  *
 205  * This function is not required to simply reference stress options and have
 206  * them fire at their default periods.
 207  */
 208 void
 209 stress_init_command(void)
 210 {
 211     unixctl_command_register("stress/list", "", 0, 1,
 212                              stress_unixctl_list, NULL);
 213     unixctl_command_register("stress/set", "option period [random | periodic]",
 214                              2, 3, stress_unixctl_set, NULL);
 215     unixctl_command_register("stress/enable", "", 0, 0,
 216                              stress_unixctl_enable, NULL);
 217     unixctl_command_register("stress/disable", "", 0, 0,
 218                              stress_unixctl_disable, NULL);
 219 }