src/test/test_bwmgt.c

   1 /* Copyright (c) 2018, The Tor Project, Inc. */
   2 /* See LICENSE for licensing information */
   3
   4 /**
   5  * \file test_bwmgt.c
   6  * \brief tests for bandwidth management / token bucket functions
   7  */
   8
   9 #define TOKEN_BUCKET_PRIVATE
  10
  11 #include "or.h"
  12 #include "test.h"
  13
  14 #include "token_bucket.h"
  15
  16 // an imaginary time, in timestamp units. Chosen so it will roll over.
  17 static const uint32_t START_TS = UINT32_MAX-10;
  18 static const int32_t KB = 1024;
  19 static const uint32_t GB = (U64_LITERAL(1) << 30);
  20
  21 static void
  22 test_bwmgt_token_buf_init(void *arg)
  23 {
  24   (void)arg;
  25   token_bucket_rw_t b;
  26
  27   token_bucket_rw_init(&b, 16*KB, 64*KB, START_TS);
  28   // Burst is correct
  29   tt_uint_op(b.cfg.burst, OP_EQ, 64*KB);
  30   // Rate is correct, within 1 percent.
  31   {
  32     uint32_t ticks_per_sec =
  33       (uint32_t) monotime_msec_to_approx_coarse_stamp_units(1000);
  34     uint32_t rate_per_sec = (b.cfg.rate * ticks_per_sec / TICKS_PER_STEP);
  35
  36     tt_uint_op(rate_per_sec, OP_GT, 16*KB-160);
  37     tt_uint_op(rate_per_sec, OP_LT, 16*KB+160);
  38   }
  39   // Bucket starts out full:
  40   tt_uint_op(b.last_refilled_at_timestamp, OP_EQ, START_TS);
  41   tt_int_op(b.read_bucket.bucket, OP_EQ, 64*KB);
  42
  43  done:
  44   ;
  45 }
  46
  47 static void
  48 test_bwmgt_token_buf_adjust(void *arg)
  49 {
  50   (void)arg;
  51   token_bucket_rw_t b;
  52
  53   token_bucket_rw_init(&b, 16*KB, 64*KB, START_TS);
  54
  55   uint32_t rate_orig = b.cfg.rate;
  56   // Increasing burst
  57   token_bucket_rw_adjust(&b, 16*KB, 128*KB);
  58   tt_uint_op(b.cfg.rate, OP_EQ, rate_orig);
  59   tt_uint_op(b.read_bucket.bucket, OP_EQ, 64*KB);
  60   tt_uint_op(b.cfg.burst, OP_EQ, 128*KB);
  61
  62   // Decreasing burst but staying above bucket
  63   token_bucket_rw_adjust(&b, 16*KB, 96*KB);
  64   tt_uint_op(b.cfg.rate, OP_EQ, rate_orig);
  65   tt_uint_op(b.read_bucket.bucket, OP_EQ, 64*KB);
  66   tt_uint_op(b.cfg.burst, OP_EQ, 96*KB);
  67
  68   // Decreasing burst below bucket,
  69   token_bucket_rw_adjust(&b, 16*KB, 48*KB);
  70   tt_uint_op(b.cfg.rate, OP_EQ, rate_orig);
  71   tt_uint_op(b.read_bucket.bucket, OP_EQ, 48*KB);
  72   tt_uint_op(b.cfg.burst, OP_EQ, 48*KB);
  73
  74   // Changing rate.
  75   token_bucket_rw_adjust(&b, 32*KB, 48*KB);
  76   tt_uint_op(b.cfg.rate, OP_GE, rate_orig*2 - 10);
  77   tt_uint_op(b.cfg.rate, OP_LE, rate_orig*2 + 10);
  78   tt_uint_op(b.read_bucket.bucket, OP_EQ, 48*KB);
  79   tt_uint_op(b.cfg.burst, OP_EQ, 48*KB);
  80
  81  done:
  82   ;
  83 }
  84
  85 static void
  86 test_bwmgt_token_buf_dec(void *arg)
  87 {
  88   (void)arg;
  89   token_bucket_rw_t b;
  90   token_bucket_rw_init(&b, 16*KB, 64*KB, START_TS);
  91
  92   // full-to-not-full.
  93   tt_int_op(0, OP_EQ, token_bucket_rw_dec_read(&b, KB));
  94   tt_int_op(b.read_bucket.bucket, OP_EQ, 63*KB);
  95
  96   // Full to almost-not-full
  97   tt_int_op(0, OP_EQ, token_bucket_rw_dec_read(&b, 63*KB - 1));
  98   tt_int_op(b.read_bucket.bucket, OP_EQ, 1);
  99
 100   // almost-not-full to empty.
 101   tt_int_op(1, OP_EQ, token_bucket_rw_dec_read(&b, 1));
 102   tt_int_op(b.read_bucket.bucket, OP_EQ, 0);
 103
 104   // reset bucket, try full-to-empty
 105   token_bucket_rw_init(&b, 16*KB, 64*KB, START_TS);
 106   tt_int_op(1, OP_EQ, token_bucket_rw_dec_read(&b, 64*KB));
 107   tt_int_op(b.read_bucket.bucket, OP_EQ, 0);
 108
 109   // reset bucket, try underflow.
 110   token_bucket_rw_init(&b, 16*KB, 64*KB, START_TS);
 111   tt_int_op(1, OP_EQ, token_bucket_rw_dec_read(&b, 64*KB + 1));
 112   tt_int_op(b.read_bucket.bucket, OP_EQ, -1);
 113
 114   // A second underflow does not make the bucket empty.
 115   tt_int_op(0, OP_EQ, token_bucket_rw_dec_read(&b, 1000));
 116   tt_int_op(b.read_bucket.bucket, OP_EQ, -1001);
 117
 118  done:
 119   ;
 120 }
 121
 122 static void
 123 test_bwmgt_token_buf_refill(void *arg)
 124 {
 125   (void)arg;
 126   token_bucket_rw_t b;
 127   const uint32_t SEC =
 128     (uint32_t)monotime_msec_to_approx_coarse_stamp_units(1000);
 129   token_bucket_rw_init(&b, 16*KB, 64*KB, START_TS);
 130
 131   /* Make the buffer much emptier, then let one second elapse. */
 132   token_bucket_rw_dec_read(&b, 48*KB);
 133   tt_int_op(b.read_bucket.bucket, OP_EQ, 16*KB);
 134   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC));
 135   tt_int_op(b.read_bucket.bucket, OP_GT, 32*KB - 300);
 136   tt_int_op(b.read_bucket.bucket, OP_LT, 32*KB + 300);
 137
 138   /* Another half second. */
 139   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*3/2));
 140   tt_int_op(b.read_bucket.bucket, OP_GT, 40*KB - 400);
 141   tt_int_op(b.read_bucket.bucket, OP_LT, 40*KB + 400);
 142   tt_uint_op(b.last_refilled_at_timestamp, OP_EQ, START_TS + SEC*3/2);
 143
 144   /* No time: nothing happens. */
 145   {
 146     const uint32_t bucket_orig = b.read_bucket.bucket;
 147     tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*3/2));
 148     tt_int_op(b.read_bucket.bucket, OP_EQ, bucket_orig);
 149   }
 150
 151   /* Another 30 seconds: fill the bucket. */
 152   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*3/2 + SEC*30));
 153   tt_int_op(b.read_bucket.bucket, OP_EQ, b.cfg.burst);
 154   tt_uint_op(b.last_refilled_at_timestamp, OP_EQ, START_TS + SEC*3/2 + SEC*30);
 155
 156   /* Another 30 seconds: nothing happens. */
 157   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*3/2 + SEC*60));
 158   tt_int_op(b.read_bucket.bucket, OP_EQ, b.cfg.burst);
 159   tt_uint_op(b.last_refilled_at_timestamp, OP_EQ, START_TS + SEC*3/2 + SEC*60);
 160
 161   /* Empty the bucket, let two seconds pass, and make sure that a refill is
 162    * noticed. */
 163   tt_int_op(1, OP_EQ, token_bucket_rw_dec_read(&b, b.cfg.burst));
 164   tt_int_op(0, OP_EQ, b.read_bucket.bucket);
 165   tt_int_op(1, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*3/2 + SEC*61));
 166   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*3/2 + SEC*62));
 167   tt_int_op(b.read_bucket.bucket, OP_GT, 32*KB-400);
 168   tt_int_op(b.read_bucket.bucket, OP_LT, 32*KB+400);
 169
 170   /* Underflow the bucket, make sure we detect when it has tokens again. */
 171   tt_int_op(1, OP_EQ,
 172             token_bucket_rw_dec_read(&b, b.read_bucket.bucket+16*KB));
 173   tt_int_op(-16*KB, OP_EQ, b.read_bucket.bucket);
 174   // half a second passes...
 175   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*64));
 176   tt_int_op(b.read_bucket.bucket, OP_GT, -8*KB-300);
 177   tt_int_op(b.read_bucket.bucket, OP_LT, -8*KB+300);
 178   // a second passes
 179   tt_int_op(1, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*65));
 180   tt_int_op(b.read_bucket.bucket, OP_GT, 8*KB-400);
 181   tt_int_op(b.read_bucket.bucket, OP_LT, 8*KB+400);
 182
 183   // We step a second backwards, and nothing happens.
 184   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*64));
 185   tt_int_op(b.read_bucket.bucket, OP_GT, 8*KB-400);
 186   tt_int_op(b.read_bucket.bucket, OP_LT, 8*KB+400);
 187
 188   // A ridiculous amount of time passes.
 189   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, INT32_MAX));
 190   tt_int_op(b.read_bucket.bucket, OP_EQ, b.cfg.burst);
 191
 192  done:
 193   ;
 194 }
 195
 196 /* Test some helper functions we use within the token bucket interface. */
 197 static void
 198 test_bwmgt_token_buf_helpers(void *arg)
 199 {
 200   uint32_t ret;
 201
 202   (void) arg;
 203
 204   /* The returned value will be OS specific but in any case, it should be
 205    * greater than 1 since we are passing 1GB/sec rate. */
 206   ret = rate_per_sec_to_rate_per_step(1 * GB);
 207   tt_u64_op(ret, OP_GT, 1);
 208
 209   /* We default to 1 in case rate is 0. */
 210   ret = rate_per_sec_to_rate_per_step(0);
 211   tt_u64_op(ret, OP_EQ, 1);
 212
 213  done:
 214   ;
 215 }
 216
 217 #define BWMGT(name)                                          \
 218   { #name, test_bwmgt_ ## name , 0, NULL, NULL }
 219
 220 struct testcase_t bwmgt_tests[] = {
 221   BWMGT(token_buf_init),
 222   BWMGT(token_buf_adjust),
 223   BWMGT(token_buf_dec),
 224   BWMGT(token_buf_refill),
 225   BWMGT(token_buf_helpers),
 226   END_OF_TESTCASES
 227 };
 228