2 This file is part of GNUnet.
3 (C) 2010 Christian Grothoff (and other contributing authors)
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13 General Public License for more details.
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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.rel_value + 500LL) / 1000LL),
90 return (b * deadline.rel_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.rel_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.rel_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;
173 uint64_t delta_avail;
177 now = GNUNET_TIME_absolute_get ();
178 delta_time = now.abs_value - av->last_update__.abs_value;
179 delta_avail = (delta_time * ((unsigned long long) av->available_bytes_per_s__) + 500LL) / 1000LL;
180 av->consumption_since_last_update__ -= delta_avail;
181 av->last_update__ = now;
182 if (av->consumption_since_last_update__ < 0)
184 left_bytes = - av->consumption_since_last_update__;
185 max_carry = av->available_bytes_per_s__ * av->max_carry_s__;
186 if (max_carry < GNUNET_SERVER_MAX_MESSAGE_SIZE)
187 max_carry = GNUNET_SERVER_MAX_MESSAGE_SIZE;
188 if (max_carry > left_bytes)
189 av->consumption_since_last_update__ = -left_bytes;
191 av->consumption_since_last_update__ = -max_carry;
194 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
195 "Tracker %p updated, have %u Bps, last update was %llu ms ago\n",
197 (unsigned int) av->available_bytes_per_s__,
198 (unsigned long long) delta_time);
205 * Notify the tracker that a certain number of bytes of bandwidth have
206 * been consumed. Note that it is legal to consume bytes even if not
207 * enough bandwidth is available (in that case,
208 * GNUNET_BANDWIDTH_tracker_get_delay may return non-zero delay values
209 * even for a size of zero for a while).
211 * @param av tracker to update
212 * @param size number of bytes consumed
213 * @return GNUNET_YES if this consumption is above the limit
216 GNUNET_BANDWIDTH_tracker_consume (struct GNUNET_BANDWIDTH_Tracker *av,
222 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
223 "Tracker %p consumes %d bytes\n",
229 nc = av->consumption_since_last_update__ + size;
230 if (nc < av->consumption_since_last_update__)
233 return GNUNET_SYSERR;
235 av->consumption_since_last_update__ = nc;
237 if (av->consumption_since_last_update__ > 0)
240 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
241 "Tracker %p consumption %llu bytes above limit\n",
243 (unsigned long long) av->consumption_since_last_update__);
250 av->consumption_since_last_update__ += size;
257 * Compute how long we should wait until consuming 'size'
258 * bytes of bandwidth in order to stay within the given
261 * @param av tracker to query
262 * @param size number of bytes we would like to consume
263 * @return time in ms to wait for consumption to be OK
265 struct GNUNET_TIME_Relative
266 GNUNET_BANDWIDTH_tracker_get_delay (struct GNUNET_BANDWIDTH_Tracker *av,
269 struct GNUNET_TIME_Relative ret;
270 int64_t bytes_needed;
272 if (av->available_bytes_per_s__ == 0)
275 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
276 "Tracker %p delay is infinity\n",
279 return GNUNET_TIME_UNIT_FOREVER_REL;
282 bytes_needed = size + av->consumption_since_last_update__;
283 if (bytes_needed <= 0)
286 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
287 "Tracker %p delay for %u bytes is zero\n",
289 (unsigned int) size);
291 return GNUNET_TIME_UNIT_ZERO;
293 ret.rel_value = 1000LL * bytes_needed / (unsigned long long) av->available_bytes_per_s__;
295 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
296 "Tracker %p delay for %u bytes is %llu ms\n",
299 (unsigned long long) ret.rel_value);
306 * Compute how many bytes are available for consumption right now.
309 * @param av tracker to query
310 * @return number of bytes available for consumption right now
313 GNUNET_BANDWIDTH_tracker_get_available (struct GNUNET_BANDWIDTH_Tracker *av)
315 struct GNUNET_BANDWIDTH_Value32NBO bps;
320 bps = GNUNET_BANDWIDTH_value_init (av->available_bytes_per_s__);
321 avail = GNUNET_BANDWIDTH_value_get_available_until (bps,
322 GNUNET_TIME_absolute_get_duration (av->last_update__));
323 used = av->consumption_since_last_update__;
325 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
326 "Tracker %p available bandwidth is %lld bytes\n",
328 (long long) (int64_t) (avail - used));
330 return (int64_t) (avail - used);
335 * Update quota of bandwidth tracker.
337 * @param av tracker to initialize
338 * @param bytes_per_second_limit new limit to assume
341 GNUNET_BANDWIDTH_tracker_update_quota (struct GNUNET_BANDWIDTH_Tracker *av,
342 struct GNUNET_BANDWIDTH_Value32NBO bytes_per_second_limit)
347 new_limit = ntohl (bytes_per_second_limit.value__);
349 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
350 "Tracker %p bandwidth changed to %u Bps\n",
352 (unsigned int) new_limit);
355 old_limit = av->available_bytes_per_s__;
356 av->available_bytes_per_s__ = new_limit;
357 if (old_limit > new_limit)
358 update_tracker (av); /* maximum excess might be less now */
362 /* end of bandwidth.c */