1 /* $KAME: altq_rmclass.c,v 1.18 2003/11/06 06:32:53 kjc Exp $ */
2 /* $DragonFly: src/sys/net/altq/altq_rmclass.c,v 1.1 2005/02/11 22:25:57 joerg Exp $ */
5 * Copyright (c) 1991-1997 Regents of the University of California.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the Network Research
19 * Group at Lawrence Berkeley Laboratory.
20 * 4. Neither the name of the University nor of the Laboratory may be used
21 * to endorse or promote products derived from this software without
22 * specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * LBL code modified by speer@eng.sun.com, May 1977.
37 * For questions and/or comments, please send mail to cbq@ee.lbl.gov
40 #ident "@(#)rm_class.c 1.48 97/12/05 SMI"
44 #include "opt_inet6.h"
46 #ifdef ALTQ_CBQ /* cbq is enabled by ALTQ_CBQ option in opt_altq.h */
48 #include <sys/param.h>
49 #include <sys/malloc.h>
51 #include <sys/socket.h>
52 #include <sys/systm.h>
53 #include <sys/callout.h>
54 #include <sys/errno.h>
59 #include <net/altq/altq.h>
60 #include <net/altq/altq_rmclass.h>
61 #include <net/altq/altq_rmclass_debug.h>
62 #include <net/altq/altq_red.h>
63 #include <net/altq/altq_rio.h>
66 static struct cbqtrace cbqtrace_buffer[NCBQTRACE+1];
67 static struct cbqtrace *cbqtrace_ptr = NULL;
68 static int cbqtrace_count;
75 #define reset_cutoff(ifd) { ifd->cutoff_ = RM_MAXDEPTH; }
81 static int rmc_satisfied(struct rm_class *, struct timeval *);
82 static void rmc_wrr_set_weights(struct rm_ifdat *);
83 static void rmc_depth_compute(struct rm_class *);
84 static void rmc_depth_recompute(rm_class_t *);
86 static struct mbuf *_rmc_wrr_dequeue_next(struct rm_ifdat *, int);
87 static struct mbuf *_rmc_prr_dequeue_next(struct rm_ifdat *, int);
89 static int _rmc_addq(rm_class_t *, struct mbuf *);
90 static void _rmc_dropq(rm_class_t *);
91 static struct mbuf *_rmc_getq(rm_class_t *);
92 static struct mbuf *_rmc_pollq(rm_class_t *);
94 static int rmc_under_limit(struct rm_class *, struct timeval *);
95 static void rmc_tl_satisfied(struct rm_ifdat *, struct timeval *);
96 static void rmc_drop_action(struct rm_class *);
97 static void rmc_restart(void *);
98 static void rmc_root_overlimit(struct rm_class *, struct rm_class *);
100 #define BORROW_OFFTIME
102 * BORROW_OFFTIME (experimental):
103 * borrow the offtime of the class borrowing from.
104 * the reason is that when its own offtime is set, the class is unable
105 * to borrow much, especially when cutoff is taking effect.
106 * but when the borrowed class is overloaded (advidle is close to minidle),
107 * use the borrowing class's offtime to avoid overload.
109 #define ADJUST_CUTOFF
111 * ADJUST_CUTOFF (experimental):
112 * if no underlimit class is found due to cutoff, increase cutoff and
113 * retry the scheduling loop.
114 * also, don't invoke delay_actions while cutoff is taking effect,
115 * since a sleeping class won't have a chance to be scheduled in the
118 * now heuristics for setting the top-level variable (cutoff_) becomes:
119 * 1. if a packet arrives for a not-overlimit class, set cutoff
120 * to the depth of the class.
121 * 2. if cutoff is i, and a packet arrives for an overlimit class
122 * with an underlimit ancestor at a lower level than i (say j),
123 * then set cutoff to j.
124 * 3. at scheduling a packet, if there is no underlimit class
125 * due to the current cutoff level, increase cutoff by 1 and
126 * then try to schedule again.
131 * rmc_newclass(...) - Create a new resource management class at priority
132 * 'pri' on the interface given by 'ifd'.
134 * nsecPerByte is the data rate of the interface in nanoseconds/byte.
135 * E.g., 800 for a 10Mb/s ethernet. If the class gets less
136 * than 100% of the bandwidth, this number should be the
137 * 'effective' rate for the class. Let f be the
138 * bandwidth fraction allocated to this class, and let
139 * nsPerByte be the data rate of the output link in
140 * nanoseconds/byte. Then nsecPerByte is set to
141 * nsPerByte / f. E.g., 1600 (= 800 / .5)
142 * for a class that gets 50% of an ethernet's bandwidth.
144 * action the routine to call when the class is over limit.
146 * maxq max allowable queue size for class (in packets).
148 * parent parent class pointer.
150 * borrow class to borrow from (should be either 'parent' or null).
152 * maxidle max value allowed for class 'idle' time estimate (this
153 * parameter determines how large an initial burst of packets
154 * can be before overlimit action is invoked.
156 * offtime how long 'delay' action will delay when class goes over
157 * limit (this parameter determines the steady-state burst
158 * size when a class is running over its limit).
160 * Maxidle and offtime have to be computed from the following: If the
161 * average packet size is s, the bandwidth fraction allocated to this
162 * class is f, we want to allow b packet bursts, and the gain of the
163 * averaging filter is g (= 1 - 2^(-RM_FILTER_GAIN)), then:
165 * ptime = s * nsPerByte * (1 - f) / f
166 * maxidle = ptime * (1 - g^b) / g^b
167 * minidle = -ptime * (1 / (f - 1))
168 * offtime = ptime * (1 + 1/(1 - g) * (1 - g^(b - 1)) / g^(b - 1)
170 * Operationally, it's convenient to specify maxidle & offtime in units
171 * independent of the link bandwidth so the maxidle & offtime passed to
172 * this routine are the above values multiplied by 8*f/(1000*nsPerByte).
173 * (The constant factor is a scale factor needed to make the parameters
174 * integers. This scaling also means that the 'unscaled' values of
175 * maxidle*nsecPerByte/8 and offtime*nsecPerByte/8 will be in microseconds,
176 * not nanoseconds.) Also note that the 'idle' filter computation keeps
177 * an estimate scaled upward by 2^RM_FILTER_GAIN so the passed value of
178 * maxidle also must be scaled upward by this value. Thus, the passed
179 * values for maxidle and offtime can be computed as follows:
181 * maxidle = maxidle * 2^RM_FILTER_GAIN * 8 / (1000 * nsecPerByte)
182 * offtime = offtime * 8 / (1000 * nsecPerByte)
184 * When USE_HRTIME is employed, then maxidle and offtime become:
185 * maxidle = maxilde * (8.0 / nsecPerByte);
186 * offtime = offtime * (8.0 / nsecPerByte);
189 rmc_newclass(int pri, struct rm_ifdat *ifd, u_int nsecPerByte,
190 void (*action)(rm_class_t *, rm_class_t *), int maxq,
191 struct rm_class *parent, struct rm_class *borrow, u_int maxidle,
192 int minidle, u_int offtime, int pktsize, int flags)
195 struct rm_class *peer;
198 if (pri >= RM_MAXPRIO)
201 if (flags & RMCF_RED) {
203 printf("rmc_newclass: RED not configured for CBQ!\n");
209 if (flags & RMCF_RIO) {
211 printf("rmc_newclass: RIO not configured for CBQ!\n");
217 cl = malloc(sizeof(*cl), M_ALTQ, M_WAITOK | M_ZERO);
218 callout_init(&cl->callout_);
219 cl->q_ = malloc(sizeof(*cl->q_), M_ALTQ, M_WAITOK | M_ZERO);
222 * Class initialization.
224 cl->children_ = NULL;
225 cl->parent_ = parent;
226 cl->borrow_ = borrow;
230 cl->allotment_ = RM_NS_PER_SEC / nsecPerByte; /* Bytes per sec */
233 cl->ns_per_byte_ = nsecPerByte;
235 qlimit(cl->q_) = maxq;
236 qtype(cl->q_) = Q_DROPHEAD;
240 #if 1 /* minidle is also scaled in ALTQ */
241 cl->minidle_ = (minidle * (int)nsecPerByte) / 8;
242 if (cl->minidle_ > 0)
245 cl->minidle_ = minidle;
247 cl->maxidle_ = (maxidle * nsecPerByte) / 8;
248 if (cl->maxidle_ == 0)
250 #if 1 /* offtime is also scaled in ALTQ */
251 cl->avgidle_ = cl->maxidle_;
252 cl->offtime_ = ((offtime * nsecPerByte) / 8) >> RM_FILTER_GAIN;
253 if (cl->offtime_ == 0)
257 cl->offtime_ = (offtime * nsecPerByte) / 8;
259 cl->overlimit = action;
262 if (flags & (RMCF_RED|RMCF_RIO)) {
263 int red_flags, red_pkttime;
266 if (flags & RMCF_ECN)
267 red_flags |= REDF_ECN;
269 if (flags & RMCF_CLEARDSCP)
270 red_flags |= RIOF_CLEARDSCP;
272 red_pkttime = nsecPerByte * pktsize / 1000;
274 if (flags & RMCF_RED) {
275 cl->red_ = red_alloc(0, 0,
276 qlimit(cl->q_) * 10/100,
277 qlimit(cl->q_) * 30/100,
278 red_flags, red_pkttime);
279 if (cl->red_ != NULL)
280 qtype(cl->q_) = Q_RED;
284 cl->red_ = (red_t *)rio_alloc(0, NULL,
285 red_flags, red_pkttime);
286 if (cl->red_ != NULL)
287 qtype(cl->q_) = Q_RIO;
291 #endif /* ALTQ_RED */
294 * put the class into the class tree
297 if ((peer = ifd->active_[pri]) != NULL) {
298 /* find the last class at this pri */
300 while (peer->peer_ != ifd->active_[pri])
304 ifd->active_[pri] = cl;
309 cl->next_ = parent->children_;
310 parent->children_ = cl;
315 * Compute the depth of this class and its ancestors in the class
318 rmc_depth_compute(cl);
321 * If CBQ's WRR is enabled, then initialize the class WRR state.
325 ifd->alloc_[pri] += cl->allotment_;
326 rmc_wrr_set_weights(ifd);
333 rmc_modclass(struct rm_class *cl, u_int nsecPerByte, int maxq, u_int maxidle,
334 int minidle, u_int offtime, int pktsize)
336 struct rm_ifdat *ifd;
341 old_allotment = cl->allotment_;
344 cl->allotment_ = RM_NS_PER_SEC / nsecPerByte; /* Bytes per sec */
346 cl->ns_per_byte_ = nsecPerByte;
348 qlimit(cl->q_) = maxq;
350 #if 1 /* minidle is also scaled in ALTQ */
351 cl->minidle_ = (minidle * nsecPerByte) / 8;
352 if (cl->minidle_ > 0)
355 cl->minidle_ = minidle;
357 cl->maxidle_ = (maxidle * nsecPerByte) / 8;
358 if (cl->maxidle_ == 0)
360 #if 1 /* offtime is also scaled in ALTQ */
361 cl->avgidle_ = cl->maxidle_;
362 cl->offtime_ = ((offtime * nsecPerByte) / 8) >> RM_FILTER_GAIN;
363 if (cl->offtime_ == 0)
367 cl->offtime_ = (offtime * nsecPerByte) / 8;
371 * If CBQ's WRR is enabled, then initialize the class WRR state.
374 ifd->alloc_[cl->pri_] += cl->allotment_ - old_allotment;
375 rmc_wrr_set_weights(ifd);
383 * rmc_wrr_set_weights(struct rm_ifdat *ifdat) - This function computes
384 * the appropriate run robin weights for the CBQ weighted round robin
391 rmc_wrr_set_weights(struct rm_ifdat *ifd)
394 struct rm_class *cl, *clh;
396 for (i = 0; i < RM_MAXPRIO; i++) {
398 * This is inverted from that of the simulator to
399 * maintain precision.
401 if (ifd->num_[i] == 0)
404 ifd->M_[i] = ifd->alloc_[i] /
405 (ifd->num_[i] * ifd->maxpkt_);
407 * Compute the weighted allotment for each class.
408 * This takes the expensive div instruction out
409 * of the main loop for the wrr scheduling path.
410 * These only get recomputed when a class comes or
413 if (ifd->active_[i] != NULL) {
414 clh = cl = ifd->active_[i];
416 /* safe-guard for slow link or alloc_ == 0 */
418 cl->w_allotment_ = 0;
420 cl->w_allotment_ = cl->allotment_ /
423 } while ((cl != NULL) && (cl != clh));
429 rmc_get_weight(struct rm_ifdat *ifd, int pri)
431 if ((pri >= 0) && (pri < RM_MAXPRIO))
432 return (ifd->M_[pri]);
439 * rmc_depth_compute(struct rm_class *cl) - This function computes the
440 * appropriate depth of class 'cl' and its ancestors.
446 rmc_depth_compute(struct rm_class *cl)
448 rm_class_t *t = cl, *p;
451 * Recompute the depth for the branch of the tree.
455 if (p && (t->depth_ >= p->depth_)) {
456 p->depth_ = t->depth_ + 1;
465 * rmc_depth_recompute(struct rm_class *cl) - This function re-computes
466 * the depth of the tree after a class has been deleted.
472 rmc_depth_recompute(rm_class_t *cl)
479 if ((t = p->children_) == NULL) {
485 if (t->depth_ > cdepth)
490 if (p->depth_ == cdepth + 1)
491 /* no change to this parent */
494 p->depth_ = cdepth + 1;
502 if (cl->depth_ >= 1) {
503 if (cl->children_ == NULL) {
505 } else if ((t = cl->children_) != NULL) {
507 if (t->children_ != NULL)
508 rmc_depth_recompute(t);
512 rmc_depth_compute(cl);
519 * rmc_delete_class(struct rm_ifdat *ifdat, struct rm_class *cl) - This
520 * function deletes a class from the link-sharing structure and frees
521 * all resources associated with the class.
527 rmc_delete_class(struct rm_ifdat *ifd, struct rm_class *cl)
529 struct rm_class *p, *head, *previous;
532 KKASSERT(cl->children_ == NULL);
535 callout_stop(&cl->callout_);
539 * Free packets in the packet queue.
540 * XXX - this may not be a desired behavior. Packets should be
546 * If the class has a parent, then remove the class from the
547 * class from the parent's children chain.
549 if (cl->parent_ != NULL) {
550 head = cl->parent_->children_;
552 if (head->next_ == NULL) {
553 KKASSERT(head == cl);
554 cl->parent_->children_ = NULL;
555 cl->parent_->leaf_ = 1;
556 } else while (p != NULL) {
559 cl->parent_->children_ = cl->next_;
561 previous->next_ = cl->next_;
572 * Delete class from class priority peer list.
574 if ((p = ifd->active_[cl->pri_]) != NULL) {
576 * If there is more than one member of this priority
577 * level, then look for class(cl) in the priority level.
580 while (p->peer_ != cl)
582 p->peer_ = cl->peer_;
584 if (ifd->active_[cl->pri_] == cl)
585 ifd->active_[cl->pri_] = cl->peer_;
588 ifd->active_[cl->pri_] = NULL;
593 * Recompute the WRR weights.
596 ifd->alloc_[cl->pri_] -= cl->allotment_;
597 ifd->num_[cl->pri_]--;
598 rmc_wrr_set_weights(ifd);
602 * Re-compute the depth of the tree.
605 rmc_depth_recompute(cl->parent_);
607 rmc_depth_recompute(ifd->root_);
613 * Free the class structure.
615 if (cl->red_ != NULL) {
617 if (q_is_rio(cl->q_))
618 rio_destroy((rio_t *)cl->red_);
621 if (q_is_red(cl->q_))
622 red_destroy(cl->red_);
625 free(cl->q_, M_ALTQ);
631 * rmc_init(...) - Initialize the resource management data structures
632 * associated with the output portion of interface 'ifp'. 'ifd' is
633 * where the structures will be built (for backwards compatibility, the
634 * structures aren't kept in the ifnet struct). 'nsecPerByte'
635 * gives the link speed (inverse of bandwidth) in nanoseconds/byte.
636 * 'restart' is the driver-specific routine that the generic 'delay
637 * until under limit' action will call to restart output. `maxq'
638 * is the queue size of the 'link' & 'default' classes. 'maxqueued'
639 * is the maximum number of packets that the resource management
640 * code will allow to be queued 'downstream' (this is typically 1).
646 rmc_init(struct ifaltq *ifq, struct rm_ifdat *ifd, u_int nsecPerByte,
647 void (*restart)(struct ifaltq *), int maxq, int maxqueued, u_int maxidle,
648 int minidle, u_int offtime, int flags)
653 * Initialize the CBQ tracing/debug facility.
657 bzero(ifd, sizeof (*ifd));
658 mtu = ifq->altq_ifp->if_mtu;
660 ifd->restart = restart;
661 ifd->maxqueued_ = maxqueued;
662 ifd->ns_per_byte_ = nsecPerByte;
664 ifd->wrr_ = (flags & RMCF_WRR) ? 1 : 0;
665 ifd->efficient_ = (flags & RMCF_EFFICIENT) ? 1 : 0;
667 ifd->maxiftime_ = mtu * nsecPerByte / 1000 * 16;
668 if (mtu * nsecPerByte > 10 * 1000000)
669 ifd->maxiftime_ /= 4;
673 CBQTRACE(rmc_init, 'INIT', ifd->cutoff_);
676 * Initialize the CBQ's WRR state.
678 for (i = 0; i < RM_MAXPRIO; i++) {
683 ifd->active_[i] = NULL;
687 * Initialize current packet state.
691 for (i = 0; i < RM_MAXQUEUED; i++) {
692 ifd->class_[i] = NULL;
694 ifd->borrowed_[i] = NULL;
698 * Create the root class of the link-sharing structure.
700 ifd->root_ = rmc_newclass(0, ifd, nsecPerByte, rmc_root_overlimit,
701 maxq, 0, 0, maxidle, minidle, offtime, 0, 0);
702 if (ifd->root_ == NULL) {
703 printf("rmc_init: root class not allocated\n");
706 ifd->root_->depth_ = 0;
711 * rmc_queue_packet(struct rm_class *cl, struct mbuf *m) - Add packet given by
712 * mbuf 'm' to queue for resource class 'cl'. This routine is called
713 * by a driver's if_output routine. This routine must be called with
714 * output packet completion interrupts locked out (to avoid racing with
717 * Returns: 0 on successful queueing
718 * -1 when packet drop occurs
721 rmc_queue_packet(struct rm_class *cl, struct mbuf *m)
724 struct rm_ifdat *ifd = cl->ifdat_;
726 int is_empty = qempty(cl->q_);
729 if (ifd->cutoff_ > 0) {
730 if (TV_LT(&cl->undertime_, &now)) {
731 if (ifd->cutoff_ > cl->depth_)
732 ifd->cutoff_ = cl->depth_;
733 CBQTRACE(rmc_queue_packet, 'ffoc', cl->depth_);
738 * the class is overlimit. if the class has
739 * underlimit ancestors, set cutoff to the lowest
742 struct rm_class *borrow = cl->borrow_;
744 while (borrow != NULL &&
745 borrow->depth_ < ifd->cutoff_) {
746 if (TV_LT(&borrow->undertime_, &now)) {
747 ifd->cutoff_ = borrow->depth_;
748 CBQTRACE(rmc_queue_packet, 'ffob', ifd->cutoff_);
751 borrow = borrow->borrow_;
755 else if ((ifd->cutoff_ > 1) && cl->borrow_) {
756 if (TV_LT(&cl->borrow_->undertime_, &now)) {
757 ifd->cutoff_ = cl->borrow_->depth_;
758 CBQTRACE(rmc_queue_packet, 'ffob',
759 cl->borrow_->depth_);
765 if (_rmc_addq(cl, m) < 0)
770 CBQTRACE(rmc_queue_packet, 'ytpe', cl->stats_.handle);
774 if (qlen(cl->q_) > qlimit(cl->q_)) {
775 /* note: qlimit can be set to 0 or 1 */
784 * rmc_tl_satisfied(struct rm_ifdat *ifd, struct timeval *now) - Check all
785 * classes to see if there are satified.
789 rmc_tl_satisfied(struct rm_ifdat *ifd, struct timeval *now)
794 for (i = RM_MAXPRIO - 1; i >= 0; i--) {
795 if ((bp = ifd->active_[i]) != NULL) {
798 if (!rmc_satisfied(p, now)) {
799 ifd->cutoff_ = p->depth_;
811 * rmc_satisfied - Return 1 of the class is satisfied. O, otherwise.
815 rmc_satisfied(struct rm_class *cl, struct timeval *now)
821 if (TV_LT(now, &cl->undertime_))
823 if (cl->depth_ == 0) {
824 if (!cl->sleeping_ && (qlen(cl->q_) > cl->qthresh_))
829 if (cl->children_ != NULL) {
832 if (!rmc_satisfied(p, now))
842 * Return 1 if class 'cl' is under limit or can borrow from a parent,
843 * 0 if overlimit. As a side-effect, this routine will invoke the
844 * class overlimit action if the class if overlimit.
848 rmc_under_limit(struct rm_class *cl, struct timeval *now)
852 struct rm_ifdat *ifd = cl->ifdat_;
854 ifd->borrowed_[ifd->qi_] = NULL;
856 * If cl is the root class, then always return that it is
857 * underlimit. Otherwise, check to see if the class is underlimit.
859 if (cl->parent_ == NULL)
863 if (TV_LT(now, &cl->undertime_))
866 callout_stop(&cl->callout_);
868 cl->undertime_.tv_sec = 0;
873 while (cl->undertime_.tv_sec && TV_LT(now, &cl->undertime_)) {
874 if (((cl = cl->borrow_) == NULL) ||
875 (cl->depth_ > ifd->cutoff_)) {
878 /* cutoff is taking effect, just
879 return false without calling
883 #ifdef BORROW_OFFTIME
885 * check if the class can borrow offtime too.
886 * borrow offtime from the top of the borrow
887 * chain if the top class is not overloaded.
890 /* cutoff is taking effect, use this class as top. */
892 CBQTRACE(rmc_under_limit, 'ffou', ifd->cutoff_);
894 if (top != NULL && top->avgidle_ == top->minidle_)
897 (p->overlimit)(p, top);
900 (p->overlimit)(p, NULL);
908 ifd->borrowed_[ifd->qi_] = cl;
913 * _rmc_wrr_dequeue_next() - This is scheduler for WRR as opposed to
914 * Packet-by-packet round robin.
916 * The heart of the weighted round-robin scheduler, which decides which
917 * class next gets to send a packet. Highest priority first, then
918 * weighted round-robin within priorites.
920 * Each able-to-send class gets to send until its byte allocation is
921 * exhausted. Thus, the active pointer is only changed after a class has
922 * exhausted its allocation.
924 * If the scheduler finds no class that is underlimit or able to borrow,
925 * then the first class found that had a nonzero queue and is allowed to
926 * borrow gets to send.
930 _rmc_wrr_dequeue_next(struct rm_ifdat *ifd, int op)
932 struct rm_class *cl = NULL, *first = NULL;
941 * if the driver polls the top of the queue and then removes
942 * the polled packet, we must return the same packet.
944 if (op == ALTDQ_REMOVE && ifd->pollcache_) {
945 cl = ifd->pollcache_;
947 if (ifd->efficient_) {
948 /* check if this class is overlimit */
949 if (cl->undertime_.tv_sec != 0 &&
950 rmc_under_limit(cl, &now) == 0)
953 ifd->pollcache_ = NULL;
957 /* mode == ALTDQ_POLL || pollcache == NULL */
958 ifd->pollcache_ = NULL;
959 ifd->borrowed_[ifd->qi_] = NULL;
964 for (cpri = RM_MAXPRIO - 1; cpri >= 0; cpri--) {
965 if (ifd->na_[cpri] == 0)
969 * Loop through twice for a priority level, if some class
970 * was unable to send a packet the first round because
971 * of the weighted round-robin mechanism.
972 * During the second loop at this level, deficit==2.
973 * (This second loop is not needed if for every class,
974 * "M[cl->pri_])" times "cl->allotment" is greater than
975 * the byte size for the largest packet in the class.)
978 cl = ifd->active_[cpri];
979 KKASSERT(cl != NULL);
981 if ((deficit < 2) && (cl->bytes_alloc_ <= 0))
982 cl->bytes_alloc_ += cl->w_allotment_;
983 if (!qempty(cl->q_)) {
984 if ((cl->undertime_.tv_sec == 0) ||
985 rmc_under_limit(cl, &now)) {
986 if (cl->bytes_alloc_ > 0 || deficit > 1)
989 /* underlimit but no alloc */
992 ifd->borrowed_[ifd->qi_] = NULL;
995 else if (first == NULL && cl->borrow_ != NULL)
996 first = cl; /* borrowing candidate */
999 cl->bytes_alloc_ = 0;
1001 } while (cl != ifd->active_[cpri]);
1004 /* first loop found an underlimit class with deficit */
1005 /* Loop on same priority level, with new deficit. */
1011 #ifdef ADJUST_CUTOFF
1013 * no underlimit class found. if cutoff is taking effect,
1014 * increase cutoff and try again.
1016 if (first != NULL && ifd->cutoff_ < ifd->root_->depth_) {
1018 CBQTRACE(_rmc_wrr_dequeue_next, 'ojda', ifd->cutoff_);
1021 #endif /* ADJUST_CUTOFF */
1023 * If LINK_EFFICIENCY is turned on, then the first overlimit
1024 * class we encounter will send a packet if all the classes
1025 * of the link-sharing structure are overlimit.
1028 CBQTRACE(_rmc_wrr_dequeue_next, 'otsr', ifd->cutoff_);
1030 if (!ifd->efficient_ || first == NULL)
1035 #if 0 /* too time-consuming for nothing */
1037 callout_stop(&cl->callout_);
1039 cl->undertime_.tv_sec = 0;
1041 ifd->borrowed_[ifd->qi_] = cl->borrow_;
1042 ifd->cutoff_ = cl->borrow_->depth_;
1045 * Deque the packet and do the book keeping...
1048 if (op == ALTDQ_REMOVE) {
1051 panic("_rmc_wrr_dequeue_next");
1056 * Update class statistics and link data.
1058 if (cl->bytes_alloc_ > 0)
1059 cl->bytes_alloc_ -= m_pktlen(m);
1061 if ((cl->bytes_alloc_ <= 0) || first == cl)
1062 ifd->active_[cl->pri_] = cl->peer_;
1064 ifd->active_[cl->pri_] = cl;
1066 ifd->class_[ifd->qi_] = cl;
1067 ifd->curlen_[ifd->qi_] = m_pktlen(m);
1068 ifd->now_[ifd->qi_] = now;
1069 ifd->qi_ = (ifd->qi_ + 1) % ifd->maxqueued_;
1072 /* mode == ALTDQ_PPOLL */
1074 ifd->pollcache_ = cl;
1080 * Dequeue & return next packet from the highest priority class that
1081 * has a packet to send & has enough allocation to send it. This
1082 * routine is called by a driver whenever it needs a new packet to
1085 static struct mbuf *
1086 _rmc_prr_dequeue_next(struct rm_ifdat *ifd, int op)
1090 struct rm_class *cl, *first = NULL;
1096 * if the driver polls the top of the queue and then removes
1097 * the polled packet, we must return the same packet.
1099 if (op == ALTDQ_REMOVE && ifd->pollcache_) {
1100 cl = ifd->pollcache_;
1102 ifd->pollcache_ = NULL;
1105 /* mode == ALTDQ_POLL || pollcache == NULL */
1106 ifd->pollcache_ = NULL;
1107 ifd->borrowed_[ifd->qi_] = NULL;
1109 #ifdef ADJUST_CUTOFF
1112 for (cpri = RM_MAXPRIO - 1; cpri >= 0; cpri--) {
1113 if (ifd->na_[cpri] == 0)
1115 cl = ifd->active_[cpri];
1116 KKASSERT(cl != NULL);
1118 if (!qempty(cl->q_)) {
1119 if ((cl->undertime_.tv_sec == 0) ||
1120 rmc_under_limit(cl, &now))
1122 if (first == NULL && cl->borrow_ != NULL)
1126 } while (cl != ifd->active_[cpri]);
1129 #ifdef ADJUST_CUTOFF
1131 * no underlimit class found. if cutoff is taking effect, increase
1132 * cutoff and try again.
1134 if (first != NULL && ifd->cutoff_ < ifd->root_->depth_) {
1138 #endif /* ADJUST_CUTOFF */
1140 * If LINK_EFFICIENCY is turned on, then the first overlimit
1141 * class we encounter will send a packet if all the classes
1142 * of the link-sharing structure are overlimit.
1145 if (!ifd->efficient_ || first == NULL)
1150 #if 0 /* too time-consuming for nothing */
1152 callout_stop(&cl->callout_);
1154 cl->undertime_.tv_sec = 0;
1156 ifd->borrowed_[ifd->qi_] = cl->borrow_;
1157 ifd->cutoff_ = cl->borrow_->depth_;
1160 * Deque the packet and do the book keeping...
1163 if (op == ALTDQ_REMOVE) {
1166 panic("_rmc_prr_dequeue_next");
1170 ifd->active_[cpri] = cl->peer_;
1172 ifd->class_[ifd->qi_] = cl;
1173 ifd->curlen_[ifd->qi_] = m_pktlen(m);
1174 ifd->now_[ifd->qi_] = now;
1175 ifd->qi_ = (ifd->qi_ + 1) % ifd->maxqueued_;
1178 /* mode == ALTDQ_POLL */
1180 ifd->pollcache_ = cl;
1187 * rmc_dequeue_next(struct rm_ifdat *ifd, struct timeval *now) - this function
1188 * is invoked by the packet driver to get the next packet to be
1189 * dequeued and output on the link. If WRR is enabled, then the
1190 * WRR dequeue next routine will determine the next packet to sent.
1191 * Otherwise, packet-by-packet round robin is invoked.
1193 * Returns: NULL, if a packet is not available or if all
1194 * classes are overlimit.
1196 * Otherwise, Pointer to the next packet.
1200 rmc_dequeue_next(struct rm_ifdat *ifd, int mode)
1202 if (ifd->queued_ >= ifd->maxqueued_)
1205 return (_rmc_wrr_dequeue_next(ifd, mode));
1207 return (_rmc_prr_dequeue_next(ifd, mode));
1211 * Update the utilization estimate for the packet that just completed.
1212 * The packet's class & the parent(s) of that class all get their
1213 * estimators updated. This routine is called by the driver's output-
1214 * packet-completion interrupt service routine.
1218 * a macro to approximate "divide by 1000" that gives 0.000999,
1219 * if a value has enough effective digits.
1220 * (on pentium, mul takes 9 cycles but div takes 46!)
1222 #define NSEC_TO_USEC(t) (((t) >> 10) + ((t) >> 16) + ((t) >> 17))
1224 rmc_update_class_util(struct rm_ifdat *ifd)
1226 int idle, avgidle, pktlen;
1227 int pkt_time, tidle;
1228 rm_class_t *cl, *borrowed;
1229 rm_class_t *borrows;
1230 struct timeval *nowp;
1233 * Get the most recent completed class.
1235 if ((cl = ifd->class_[ifd->qo_]) == NULL)
1238 pktlen = ifd->curlen_[ifd->qo_];
1239 borrowed = ifd->borrowed_[ifd->qo_];
1242 PKTCNTR_ADD(&cl->stats_.xmit_cnt, pktlen);
1245 * Run estimator on class and its ancestors.
1248 * rm_update_class_util is designed to be called when the
1249 * transfer is completed from a xmit complete interrupt,
1250 * but most drivers don't implement an upcall for that.
1251 * so, just use estimated completion time.
1252 * as a result, ifd->qi_ and ifd->qo_ are always synced.
1254 nowp = &ifd->now_[ifd->qo_];
1255 /* get pkt_time (for link) in usec */
1256 #if 1 /* use approximation */
1257 pkt_time = ifd->curlen_[ifd->qo_] * ifd->ns_per_byte_;
1258 pkt_time = NSEC_TO_USEC(pkt_time);
1260 pkt_time = ifd->curlen_[ifd->qo_] * ifd->ns_per_byte_ / 1000;
1262 #if 1 /* ALTQ4PPP */
1263 if (TV_LT(nowp, &ifd->ifnow_)) {
1267 * make sure the estimated completion time does not go
1268 * too far. it can happen when the link layer supports
1269 * data compression or the interface speed is set to
1270 * a much lower value.
1272 TV_DELTA(&ifd->ifnow_, nowp, iftime);
1273 if (iftime+pkt_time < ifd->maxiftime_) {
1274 TV_ADD_DELTA(&ifd->ifnow_, pkt_time, &ifd->ifnow_);
1276 TV_ADD_DELTA(nowp, ifd->maxiftime_, &ifd->ifnow_);
1279 TV_ADD_DELTA(nowp, pkt_time, &ifd->ifnow_);
1282 if (TV_LT(nowp, &ifd->ifnow_)) {
1283 TV_ADD_DELTA(&ifd->ifnow_, pkt_time, &ifd->ifnow_);
1285 TV_ADD_DELTA(nowp, pkt_time, &ifd->ifnow_);
1289 while (cl != NULL) {
1290 TV_DELTA(&ifd->ifnow_, &cl->last_, idle);
1291 if (idle >= 2000000)
1293 * this class is idle enough, reset avgidle.
1294 * (TV_DELTA returns 2000000 us when delta is large.)
1296 cl->avgidle_ = cl->maxidle_;
1298 /* get pkt_time (for class) in usec */
1299 #if 1 /* use approximation */
1300 pkt_time = pktlen * cl->ns_per_byte_;
1301 pkt_time = NSEC_TO_USEC(pkt_time);
1303 pkt_time = pktlen * cl->ns_per_byte_ / 1000;
1307 avgidle = cl->avgidle_;
1308 avgidle += idle - (avgidle >> RM_FILTER_GAIN);
1309 cl->avgidle_ = avgidle;
1311 /* Are we overlimit ? */
1313 CBQTRACE(rmc_update_class_util, 'milo', cl->stats_.handle);
1316 * need some lower bound for avgidle, otherwise
1317 * a borrowing class gets unbounded penalty.
1319 if (avgidle < cl->minidle_)
1320 avgidle = cl->avgidle_ = cl->minidle_;
1322 /* set next idle to make avgidle 0 */
1324 (((1 - RM_POWER) * avgidle) >> RM_FILTER_GAIN);
1325 TV_ADD_DELTA(nowp, tidle, &cl->undertime_);
1329 (avgidle > cl->maxidle_) ? cl->maxidle_ : avgidle;
1330 cl->undertime_.tv_sec = 0;
1331 if (cl->sleeping_) {
1332 callout_stop(&cl->callout_);
1337 if (borrows != NULL) {
1339 ++cl->stats_.borrows;
1343 cl->last_ = ifd->ifnow_;
1344 cl->last_pkttime_ = pkt_time;
1347 if (cl->parent_ == NULL) {
1348 /* take stats of root class */
1349 PKTCNTR_ADD(&cl->stats_.xmit_cnt, pktlen);
1357 * Check to see if cutoff needs to set to a new level.
1359 cl = ifd->class_[ifd->qo_];
1360 if (borrowed && (ifd->cutoff_ >= borrowed->depth_)) {
1362 if ((qlen(cl->q_) <= 0) || TV_LT(nowp, &borrowed->undertime_)) {
1363 rmc_tl_satisfied(ifd, nowp);
1364 CBQTRACE(rmc_update_class_util, 'broe', ifd->cutoff_);
1366 ifd->cutoff_ = borrowed->depth_;
1367 CBQTRACE(rmc_update_class_util, 'ffob', borrowed->depth_);
1370 if ((qlen(cl->q_) <= 1) || TV_LT(&now, &borrowed->undertime_)) {
1373 rmc_tl_satisfied(ifd, &now);
1375 CBQTRACE(rmc_update_class_util, 'broe', ifd->cutoff_);
1377 ifd->cutoff_ = borrowed->depth_;
1378 CBQTRACE(rmc_update_class_util, 'ffob', borrowed->depth_);
1384 * Release class slot
1386 ifd->borrowed_[ifd->qo_] = NULL;
1387 ifd->class_[ifd->qo_] = NULL;
1388 ifd->qo_ = (ifd->qo_ + 1) % ifd->maxqueued_;
1394 * rmc_drop_action(struct rm_class *cl) - Generic (not protocol-specific)
1395 * over-limit action routines. These get invoked by rmc_under_limit()
1396 * if a class with packets to send if over its bandwidth limit & can't
1397 * borrow from a parent class.
1403 rmc_drop_action(struct rm_class *cl)
1405 struct rm_ifdat *ifd = cl->ifdat_;
1407 KKASSERT(qlen(cl->q_) > 0);
1410 ifd->na_[cl->pri_]--;
1413 void rmc_dropall(struct rm_class *cl)
1415 struct rm_ifdat *ifd = cl->ifdat_;
1417 if (!qempty(cl->q_)) {
1420 ifd->na_[cl->pri_]--;
1426 * rmc_delay_action(struct rm_class *cl) - This function is the generic CBQ
1427 * delay action routine. It is invoked via rmc_under_limit when the
1428 * packet is discoverd to be overlimit.
1430 * If the delay action is result of borrow class being overlimit, then
1431 * delay for the offtime of the borrowing class that is overlimit.
1437 rmc_delay_action(struct rm_class *cl, struct rm_class *borrow)
1439 int delay, t, extradelay;
1441 cl->stats_.overactions++;
1442 TV_DELTA(&cl->undertime_, &cl->overtime_, delay);
1443 #ifndef BORROW_OFFTIME
1444 delay += cl->offtime_;
1447 if (!cl->sleeping_) {
1448 CBQTRACE(rmc_delay_action, 'yled', cl->stats_.handle);
1449 #ifdef BORROW_OFFTIME
1451 extradelay = borrow->offtime_;
1454 extradelay = cl->offtime_;
1458 * XXX recalculate suspend time:
1459 * current undertime is (tidle + pkt_time) calculated
1460 * from the last transmission.
1461 * tidle: time required to bring avgidle back to 0
1462 * pkt_time: target waiting time for this class
1463 * we need to replace pkt_time by offtime
1465 extradelay -= cl->last_pkttime_;
1467 if (extradelay > 0) {
1468 TV_ADD_DELTA(&cl->undertime_, extradelay, &cl->undertime_);
1469 delay += extradelay;
1473 cl->stats_.delays++;
1476 * Since packets are phased randomly with respect to the
1477 * clock, 1 tick (the next clock tick) can be an arbitrarily
1478 * short time so we have to wait for at least two ticks.
1479 * NOTE: If there's no other traffic, we need the timer as
1480 * a 'backstop' to restart this class.
1482 if (delay > tick * 2)
1483 t = (delay + tick - 1) / tick;
1486 callout_reset(&cl->callout_, t, rmc_restart, cl);
1492 * rmc_restart() - is just a helper routine for rmc_delay_action -- it is
1493 * called by the system timer code & is responsible checking if the
1494 * class is still sleeping (it might have been restarted as a side
1495 * effect of the queue scan on a packet arrival) and, if so, restarting
1496 * output for the class. Inspecting the class state & restarting output
1497 * require locking the class structure. In general the driver is
1498 * responsible for locking but this is the only routine that is not
1499 * called directly or indirectly from the interface driver so it has
1500 * know about system locking conventions. Under bsd, locking is done
1501 * by raising IPL to splimp so that's what's implemented here. On a
1502 * different system this would probably need to be changed.
1508 rmc_restart(void *arg)
1510 struct rm_class *cl = arg;
1511 struct rm_ifdat *ifd = cl->ifdat_;
1515 if (cl->sleeping_) {
1517 cl->undertime_.tv_sec = 0;
1519 if (ifd->queued_ < ifd->maxqueued_ && ifd->restart != NULL) {
1520 CBQTRACE(rmc_restart, 'trts', cl->stats_.handle);
1521 (ifd->restart)(ifd->ifq_);
1529 * rmc_root_overlimit(struct rm_class *cl) - This the generic overlimit
1530 * handling routine for the root class of the link sharing structure.
1536 rmc_root_overlimit(struct rm_class *cl, struct rm_class *borrow)
1538 panic("rmc_root_overlimit");
1542 * Packet Queue handling routines. Eventually, this is to localize the
1543 * effects on the code whether queues are red queues or droptail
1548 _rmc_addq(rm_class_t *cl, struct mbuf *m)
1551 if (q_is_rio(cl->q_))
1552 return rio_addq((rio_t *)cl->red_, cl->q_, m, cl->pktattr_);
1555 if (q_is_red(cl->q_))
1556 return red_addq(cl->red_, cl->q_, m, cl->pktattr_);
1557 #endif /* ALTQ_RED */
1559 if (cl->flags_ & RMCF_CLEARDSCP)
1560 write_dsfield(m, cl->pktattr_, 0);
1566 /* note: _rmc_dropq is not called for red */
1568 _rmc_dropq(rm_class_t *cl)
1572 if ((m = _getq(cl->q_)) != NULL)
1576 static struct mbuf *
1577 _rmc_getq(rm_class_t *cl)
1580 if (q_is_rio(cl->q_))
1581 return rio_getq((rio_t *)cl->red_, cl->q_);
1584 if (q_is_red(cl->q_))
1585 return red_getq(cl->red_, cl->q_);
1587 return _getq(cl->q_);
1590 static struct mbuf *
1591 _rmc_pollq(rm_class_t *cl)
1593 return qhead(cl->q_);
1598 * DDB hook to trace cbq events:
1599 * the last 1024 events are held in a circular buffer.
1600 * use "call cbqtrace_dump(N)" to display 20 events from Nth event.
1602 void cbqtrace_dump(int);
1603 static char *rmc_funcname(void *);
1605 static struct rmc_funcs {
1609 rmc_init, "rmc_init",
1610 rmc_queue_packet, "rmc_queue_packet",
1611 rmc_under_limit, "rmc_under_limit",
1612 rmc_update_class_util, "rmc_update_class_util",
1613 rmc_delay_action, "rmc_delay_action",
1614 rmc_restart, "rmc_restart",
1615 _rmc_wrr_dequeue_next, "_rmc_wrr_dequeue_next",
1619 static char *rmc_funcname(void *func)
1621 struct rmc_funcs *fp;
1623 for (fp = rmc_funcs; fp->func != NULL; fp++) {
1624 if (fp->func == func)
1632 cbqtrace_dump(int counter)
1637 counter = counter % NCBQTRACE;
1638 p = (int *)&cbqtrace_buffer[counter];
1640 for (i=0; i<20; i++) {
1641 printf("[0x%x] ", *p++);
1642 printf("%s: ", rmc_funcname((void *)*p++));
1644 printf("%c%c%c%c: ", cp[0], cp[1], cp[2], cp[3]);
1645 printf("%d\n",*p++);
1647 if (p >= (int *)&cbqtrace_buffer[NCBQTRACE])
1648 p = (int *)cbqtrace_buffer;
1651 #endif /* CBQ_TRACE */
1652 #endif /* ALTQ_CBQ */