2 This file is part of GNUnet.
3 (C) 2010 Christian Grothoff (and other contributing authors)
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22 * @file util/bandwidth.c
23 * @brief functions related to bandwidth (unit)
24 * @author Christian Grothoff
27 #include "gnunet_bandwidth_lib.h"
28 #include "gnunet_server_lib.h"
30 #define DEBUG_BANDWIDTH GNUNET_NO
33 * Create a new bandwidth value.
35 * @param bytes_per_second value to create
36 * @return the new bandwidth value
38 struct GNUNET_BANDWIDTH_Value32NBO
39 GNUNET_BANDWIDTH_value_init (uint32_t bytes_per_second)
41 struct GNUNET_BANDWIDTH_Value32NBO ret;
44 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
45 "Initializing bandwidth of %u bps\n",
46 (unsigned int) bytes_per_second);
48 ret.value__ = htonl (bytes_per_second);
54 * Compute the MIN of two bandwidth values.
56 * @param b1 first value
57 * @param b2 second value
58 * @return the min of b1 and b2
60 struct GNUNET_BANDWIDTH_Value32NBO
61 GNUNET_BANDWIDTH_value_min (struct GNUNET_BANDWIDTH_Value32NBO b1,
62 struct GNUNET_BANDWIDTH_Value32NBO b2)
64 return GNUNET_BANDWIDTH_value_init (GNUNET_MIN (ntohl (b1.value__),
70 * At the given bandwidth, calculate how much traffic will be
71 * available until the given deadline.
73 * @param bps bandwidth
74 * @param deadline when is the deadline
75 * @return number of bytes available at bps until deadline
78 GNUNET_BANDWIDTH_value_get_available_until (struct GNUNET_BANDWIDTH_Value32NBO bps,
79 struct GNUNET_TIME_Relative deadline)
83 b = ntohl (bps.value__);
85 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
86 "Bandwidth has %llu bytes available until deadline in %llums\n",
87 (unsigned long long) ((b * deadline.value + 500LL) / 1000LL),
90 return (b * deadline.value + 500LL) / 1000LL;
95 * At the given bandwidth, calculate how long it would take for
96 * 'size' bytes to be transmitted.
98 * @param bps bandwidth
99 * @param size number of bytes we want to have available
100 * @return how long it would take
102 struct GNUNET_TIME_Relative
103 GNUNET_BANDWIDTH_value_get_delay_for (struct GNUNET_BANDWIDTH_Value32NBO bps,
107 struct GNUNET_TIME_Relative ret;
109 b = ntohl (bps.value__);
113 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
114 "Bandwidth suggests delay of infinity (zero bandwidth)\n");
116 return GNUNET_TIME_UNIT_FOREVER_REL;
118 ret.value = size * 1000LL / b;
120 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
121 "Bandwidth suggests delay of %llu ms for %llu bytes of traffic\n",
122 (unsigned long long) ret.value,
123 (unsigned long long) size);
130 * Initialize bandwidth tracker. Note that in addition to the
131 * 'max_carry_s' limit, we also always allow at least
132 * GNUNET_SERVER_MAX_MESSAGE_SIZE to accumulate. So if the
133 * bytes-per-second limit is so small that within 'max_carry_s' not
134 * even GNUNET_SERVER_MAX_MESSAGE_SIZE is allowed to accumulate, it is
135 * ignored and replaced by GNUNET_SERVER_MAX_MESSAGE_SIZE (which is in
138 * @param av tracker to initialize
139 * @param bytes_per_second_limit initial limit to assume
140 * @param max_carry_s maximum number of seconds unused bandwidth
141 * may accumulate before it expires
144 GNUNET_BANDWIDTH_tracker_init (struct GNUNET_BANDWIDTH_Tracker *av,
145 struct GNUNET_BANDWIDTH_Value32NBO bytes_per_second_limit,
146 uint32_t max_carry_s)
148 av->consumption_since_last_update__ = 0;
149 av->last_update__ = GNUNET_TIME_absolute_get ();
150 av->available_bytes_per_s__ = ntohl (bytes_per_second_limit.value__);
151 av->max_carry_s__ = max_carry_s;
153 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
154 "Tracker %p initialized with %u bps and max carry %u\n",
156 (unsigned int) av->available_bytes_per_s__,
157 (unsigned int) max_carry_s);
163 * Update the tracker, looking at the current time and
164 * bandwidth consumption data.
166 * @param av tracker to update
169 update_tracker (struct GNUNET_BANDWIDTH_Tracker *av)
171 struct GNUNET_TIME_Absolute now;
172 uint64_t avail_per_ms;
174 uint64_t delta_avail;
176 uint64_t left_time_ms;
178 now = GNUNET_TIME_absolute_get ();
179 delta_time = now.value - av->last_update__.value;
180 delta_avail = (delta_time * ((unsigned long long) av->available_bytes_per_s__) + 500LL) / 1000LL;
181 if (av->consumption_since_last_update__ >= delta_avail)
183 av->consumption_since_last_update__ -= delta_avail;
184 av->last_update__ = now;
188 left_bytes = delta_avail - av->consumption_since_last_update__;
189 avail_per_ms = ((unsigned long long) av->available_bytes_per_s__ + 500LL) / 1000LL;
190 if (avail_per_ms > 0)
192 left_time_ms = left_bytes / avail_per_ms;
193 if (left_time_ms > ((unsigned long long) av->max_carry_s__) * 1000LL)
195 /* need to limit accumulation of unused bandwidth */
196 left_time_ms = ((unsigned long long) av->max_carry_s__) * 1000LL;
197 if (left_time_ms * avail_per_ms < GNUNET_SERVER_MAX_MESSAGE_SIZE)
199 /* need to still allow GNUNET_SERVER_MAX_MESSAGE_SIZE accumulation */
200 if (left_bytes > GNUNET_SERVER_MAX_MESSAGE_SIZE)
201 left_bytes = GNUNET_SERVER_MAX_MESSAGE_SIZE;
202 left_time_ms = left_bytes / avail_per_ms;
210 av->consumption_since_last_update__ = 0;
211 av->last_update__.value = now.value - left_time_ms;
214 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
215 "Tracker %p updated, have %u bps last update was %llu ms ago\n",
217 (unsigned int) av->available_bytes_per_s__,
218 (unsigned long long) (now.value - av->last_update__.value));
224 * Notify the tracker that a certain number of bytes of bandwidth have
225 * been consumed. Note that it is legal to consume bytes even if not
226 * enough bandwidth is available (in that case,
227 * GNUNET_BANDWIDTH_tracker_get_delay may return non-zero delay values
228 * even for a size of zero for a while).
230 * @param av tracker to update
231 * @param size number of bytes consumed
232 * @return GNUNET_YES if this consumption is above the limit
235 GNUNET_BANDWIDTH_tracker_consume (struct GNUNET_BANDWIDTH_Tracker *av,
241 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
242 "Tracker %p consumes %d bytes\n",
248 nc = av->consumption_since_last_update__ + size;
249 if (nc < av->consumption_since_last_update__)
252 return GNUNET_SYSERR;
254 av->consumption_since_last_update__ = nc;
256 if (av->consumption_since_last_update__ > 0)
259 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
260 "Tracker %p consumption %llu bytes above limit\n",
262 (unsigned long long) av->consumption_since_last_update__);
269 av->last_update__.value -= ((-size) * av->available_bytes_per_s__ + 500LL) / 1000LL;
277 * Compute how long we should wait until consuming 'size'
278 * bytes of bandwidth in order to stay within the given
281 * @param av tracker to query
282 * @param size number of bytes we would like to consume
283 * @return time to wait for consumption to be OK
285 struct GNUNET_TIME_Relative
286 GNUNET_BANDWIDTH_tracker_get_delay (struct GNUNET_BANDWIDTH_Tracker *av,
289 struct GNUNET_TIME_Relative ret;
290 struct GNUNET_TIME_Absolute now;
291 uint64_t delta_avail;
293 uint64_t bytes_needed;
295 if (av->available_bytes_per_s__ == 0)
298 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
299 "Tracker %p delay is infinity\n",
302 return GNUNET_TIME_UNIT_FOREVER_REL;
305 now = GNUNET_TIME_absolute_get ();
306 delta_time = now.value - av->last_update__.value;
307 delta_avail = (delta_time * ((unsigned long long) av->available_bytes_per_s__) + 500LL) / 1000LL;
308 if (delta_avail >= size)
311 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
312 "Tracker %p delay for %u bytes is zero\n",
314 (unsigned int) size);
316 return GNUNET_TIME_UNIT_ZERO;
318 bytes_needed = size - delta_avail;
319 ret.value = 1000LL * bytes_needed / (unsigned long long) av->available_bytes_per_s__;
321 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
322 "Tracker %p delay for %u bytes is %llu ms\n",
325 (unsigned long long) ret.value);
332 * Compute how many bytes are available for consumption right now.
335 * @param av tracker to query
336 * @return number of bytes available for consumption right now
339 GNUNET_BANDWIDTH_tracker_get_available (struct GNUNET_BANDWIDTH_Tracker *av)
341 struct GNUNET_BANDWIDTH_Value32NBO bps;
346 bps = GNUNET_BANDWIDTH_value_init (av->available_bytes_per_s__);
347 avail = GNUNET_BANDWIDTH_value_get_available_until (bps,
348 GNUNET_TIME_absolute_get_duration (av->last_update__));
349 used = av->consumption_since_last_update__;
351 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
352 "Tracker %p available bandwith is %lld ms\n",
354 (long long) (int64_t) (avail - used));
356 return (int64_t) (avail - used);
361 * Update quota of bandwidth tracker.
363 * @param av tracker to initialize
364 * @param bytes_per_second_limit new limit to assume
367 GNUNET_BANDWIDTH_tracker_update_quota (struct GNUNET_BANDWIDTH_Tracker *av,
368 struct GNUNET_BANDWIDTH_Value32NBO bytes_per_second_limit)
373 new_limit = ntohl (bytes_per_second_limit.value__);
375 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
376 "Tracker %p bandwith changed to %u bps\n",
378 (unsigned int) new_limit);
381 old_limit = av->available_bytes_per_s__;
382 av->available_bytes_per_s__ = new_limit;
383 if (old_limit > new_limit)
384 update_tracker (av); /* maximum excess might be less now */
388 /* end of bandwidth.c */