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Message-ID: <87skxxb8br.fsf@pirx.pps.jussieu.fr>
Date: Tue, 08 Apr 2008 00:37:12 +0200
From: Juliusz Chroboczek <jch@....jussieu.fr>
To: netdev@...r.kernel.org
Subject: [PATCH] Stochastic Fair Blue queue discipline
Hello,
The attached is an implementation of the Stochastic Fair Blue queue
discipline for Linux.
I would like to request a review of the following code, and whether it
is worthwile to add the Kconfig bits and submit it for inclusion into
the mainline kernel.
You will find a ready to build tarball on
http://www.pps.jussieu.fr/~jch/software/files/sch_sfb-20080407.tar.gz
http://www.pps.jussieu.fr/~jch/software/files/sch_sfb-20080407.tar.gz.asc
and a short description on
http://www.pps.jussieu.fr/~jch/software/sfb/
Thanks,
Juliusz Chroboczek
diff -urN empty/Makefile sch_sfb/Makefile
--- empty/Makefile 1970-01-01 01:00:00.000000000 +0100
+++ sch_sfb/Makefile 2008-04-08 00:28:43.000000000 +0200
@@ -0,0 +1,11 @@
+KERNEL_SOURCE=/lib/modules/$(shell uname -r)/build
+
+obj-m += sch_sfb.o
+
+all:
+ make -C $(KERNEL_SOURCE) M=$(PWD) modules
+
+clean:
+ make -C $(KERNEL_SOURCE) M=$(PWD) clean
+ -rm -f *~ Module.symvers
+
diff -urN empty/README sch_sfb/README
--- empty/README 1970-01-01 01:00:00.000000000 +0100
+++ sch_sfb/README 2008-04-08 00:28:43.000000000 +0200
@@ -0,0 +1,160 @@
+ Stochastic Fair Blue for Linux
+ ******************************
+
+
+Sch_sfb is an implementation of the Stochastic Fair Blue (SFB) queue
+management algorithm for Linux. SFB is described in
+
+ Stochastic Fair Blue: A Queue Management Algorithm for Enforcing
+ Fairness. Wu-chang Feng, Dilip D. Kandlur, Debanjan Saha and
+ Kang G. Shin. Proc. INFOCOM'01. 2001.
+
+SFB aims to keep your queues short while avoiding packet drops,
+maximising link utilisation and preserving fairness between flows.
+SFB will detect flows that do not respond to congestion indications,
+and limit them to a constant share of the link's capacity.
+
+SFB only deals with marking and/or droping packets. Reordering of
+packets is handled by sfb's child qdisc; by default, this is pfifo,
+meaning that no reordering will happen. You may want to use something
+like prio or sfq as sfb's child.
+
+Unlike most other fair queueing policies, SFB doesn't actually keep
+per-flow state; it manages flow information using a Bloom filter,
+which means that hash collisions are reduced to a minimum while using
+fairly little memory.
+
+
+Differences from the paper
+**************************
+
+This implementation takes the minimum of the mark probabilities of all
+matching buckets, rather than the maximum, as suggested in the paper.
+Either the paper is wrong, or I don't understand how Bloom filters
+work.
+
+If an aggregate has a very high marking rate, then either it is
+unresponsive, or we are badly congested. In either case, it is a good
+idea to start dropping packets rather than just marking them. If pm
+is below 1/2, we mark with probability pm; if pm is larger than 1/2,
+then we drop with probability pm * (2 * pm - 1/2), and mark with
+probability pm * (3/2 - 2 * pm).
+
+
+Quick start:
+************
+
+ tc qdisc add dev eth0 root handle 1: sfb
+
+Sfb only deals with marking/dropping packets, but doesn't reorder
+them. You may want to put a reordering qdisc below sfb.
+
+ tc qdisc add dev eth0 handle 2: parent 1: prio
+
+Since sfb penalises inelastic flows rather severely, you may want to
+put another qdisc above sfb to bypass sfb for such flows. And of
+course if you're rate-limiting (e.g. using cbq, tbf or htb) you'll
+want to do that above sfb.
+
+If you have the patched version of tc (see below), you may set
+non-default values and see some of sfb's statistics:
+
+ tc qdisc add dev eth0 root handle 1: sfb target 30 max 50 penalty_rate 100
+ tc -s qdisc show dev eth0
+
+
+Building
+********
+
+ $ cd sch_sfb/
+ $ make KERNEL_SOURCE=/usr/src/linux
+ $ insmod ./sch_sfb.ko
+
+You will also want to patch your tc tool; a patch for current versions
+of iproute2 is in the file iproute-sfb.patch.
+
+
+Parameters
+**********
+
+hash-type: one of ``flow'' (per-flow hashing), ``source'' (hash on the
+source IP address), ``dest'' (hash on the destination address), or
+``source-dest'' (hash on both the source and destination addresses).
+
+hashes HASHES, buckets BUCKETS: the size of the Bloom filter to use.
+The amount of space used is proportional to HASHES x BUCKETS, and the
+per-packet CPU time is roughly proportional to HASHES.
+
+rehash SECS: specifies how often we will switch to a fresh Bloom
+filter and a different set of hash functions. Since Bloom filters are
+more resistent to hash collisions that hash tables, this may be set to
+a fairly large value.
+
+db SECS: specifies fow how long we will perform double-buffering
+before switching to a new Bloom filter. This should be long enough to
+make sure that the new filter is ``primed'' before it is used, a few
+tens of seconds should be enough.
+
+limit PACKETS: the hard limit on the number of packets in sfb's queue.
+Set it to some large value, it should never be reached anyway.
+
+target PACKETS: the target per-flow queue size in packets. sfb will
+try to keep each per-aggregate queue between 0 and target.
+
+max PACKETS: the maximum number of packets queued for a given aggregate.
+It should be very slightly larger than target, in order to absorb
+transient bursts. Setting this to more than roughly 1.5 times target
+will cause instabilities that Blue is not designed to cope with.
+
+increment FLOAT, decrement FLOAT: the values by which per-flow
+dropping probability is in/decreased on queue under/overflow. These
+should be a small fraction of a percent, and increment should be a few
+times smaller than decrement.
+
+penalty_rate PPS, penalty_burst PACKETS: when a flow doesn't back off
+in response to congestion indication, sbf will categorise it as
+``non-reactive'' and will rate-limit it. Penalty-rate specifies the
+total throughput that non-reactive flows are allowed to use; burst is
+the size of the token bucket. You should set penalty_rate to some
+reasonable fraction of your up-link throughput (the default values are
+probably too small).
+
+
+Statistics
+**********
+
+ $ tc -s qdisc show dev eth1
+ ...
+ qdisc sfb 2: dev eth1 parent 1: hash flow limit 1000 max 30 target 20
+ increment 0.00050 decrement 0.00005 penalty rate 10 burst 20 (600s 60s 8x24)
+ Sent 9317012 bytes 74577 pkt (dropped 3165, overlimits 3235 requeues 58519)
+ rate 0bit 0pps backlog 0b 0p requeues 58519
+ earlydrop 2196 ratedrop 0 bucketdrop 969 queuedrop 0 marked 70
+ maxqlen 0 maxprob 0.01494
+
+earlydrop: the number of packets dropped before a per-flow queue was full.
+
+ratedrop: the number of packets dropped because of rate-limiting.
+
+bucketdrop: the number of packets dropped because a per-flow queue was
+full.
+
+queuedrop: the number of packets dropped due to reaching limit. This
+should normally be 0.
+
+marked: the number of packets marked with ECN.
+
+maxqlen: the length of the longest per-flow (virtual) queue.
+
+maxprob: the maximum per-flow drop probability. 1 means that some
+flows have been detected as non-reactive.
+
+
+If ratedrop is high, you're sending your non-reactive flows through
+sfb; this may not be a good idea. If bucketdrop is high, you're
+probably sending a lot of aggressive short-lived flows through sfb.
+If queuedrop is not 0, something is wrong.
+
+
+ Juliusz Chroboczek
+ <jch@....jussieu.fr>
diff -urN empty/sch_sfb.c sch_sfb/sch_sfb.c
--- empty/sch_sfb.c 1970-01-01 01:00:00.000000000 +0100
+++ sch_sfb/sch_sfb.c 2008-04-08 00:29:14.000000000 +0200
@@ -0,0 +1,687 @@
+/*
+ * sch_sfb.c Stochastic Fair Blue
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * Authors: Juliusz Chroboczek <jch@....jussieu.fr>
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/skbuff.h>
+#include <linux/random.h>
+#include <linux/jhash.h>
+#include <net/ip.h>
+#include <net/pkt_sched.h>
+#include <net/inet_ecn.h>
+
+#include "sfb.h"
+
+struct bucket {
+ u16 qlen;
+ u16 pm;
+};
+
+struct sfb_sched_data
+{
+ u16 numhashes, numbuckets;
+ u16 rehash_interval, db_interval;
+ u16 max, target;
+ u16 increment, decrement;
+ u32 limit;
+ u32 penalty_rate, penalty_burst;
+ u32 tokens_avail;
+ psched_time_t rehash_time, token_time;
+
+ u8 hash_type;
+ u8 filter;
+ u8 double_buffering;
+ u32 perturbation[2][MAXHASHES];
+ struct bucket buckets[2][MAXHASHES][MAXBUCKETS];
+ struct Qdisc *qdisc;
+
+ __u32 earlydrop, penaltydrop, bucketdrop, queuedrop, marked;
+};
+
+static unsigned sfb_hash(struct sk_buff *skb, int hash, int filter,
+ struct sfb_sched_data *q)
+{
+ u32 h, h2;
+ u8 hash_type = q->hash_type;
+
+ switch (skb->protocol) {
+ case __constant_htons(ETH_P_IP):
+ {
+ const struct iphdr *iph = ip_hdr(skb);
+ h = hash_type == SFB_HASH_SOURCE ? 0 : iph->daddr;
+ h2 = hash_type == SFB_HASH_DEST ? 0 : iph->saddr;
+ if (hash_type == SFB_HASH_FLOW) {
+ h2 ^= iph->protocol;
+ if(!(iph->frag_off&htons(IP_MF|IP_OFFSET)) &&
+ (iph->protocol == IPPROTO_TCP ||
+ iph->protocol == IPPROTO_UDP ||
+ iph->protocol == IPPROTO_UDPLITE ||
+ iph->protocol == IPPROTO_SCTP ||
+ iph->protocol == IPPROTO_DCCP ||
+ iph->protocol == IPPROTO_ESP)) {
+ h2 ^= *(((u32*)iph) + iph->ihl);
+ }
+ }
+ break;
+ }
+ case __constant_htons(ETH_P_IPV6):
+ {
+ struct ipv6hdr *iph = ipv6_hdr(skb);
+ h = hash_type == SFB_HASH_SOURCE ? 0 :
+ iph->daddr.s6_addr32[1] ^ iph->daddr.s6_addr32[3];
+ h2 = hash_type == SFB_HASH_DEST ? 0 :
+ iph->saddr.s6_addr32[1] ^ iph->saddr.s6_addr32[3];
+ if (hash_type == SFB_HASH_FLOW) {
+ h2 ^= iph->nexthdr;
+ if(iph->nexthdr == IPPROTO_TCP ||
+ iph->nexthdr == IPPROTO_UDP ||
+ iph->nexthdr == IPPROTO_UDPLITE ||
+ iph->nexthdr == IPPROTO_SCTP ||
+ iph->nexthdr == IPPROTO_DCCP ||
+ iph->nexthdr == IPPROTO_ESP)
+ h2 ^= *(u32*)&iph[1];
+ }
+ break;
+ }
+ default:
+ h = skb->protocol;
+ if(hash_type != SFB_HASH_SOURCE)
+ h ^= (u32)(unsigned long)skb->dst;
+ h2 = hash_type == SFB_HASH_FLOW ?
+ (u32)(unsigned long)skb->sk : 0;
+ }
+
+ return jhash_2words(h, h2, q->perturbation[filter][hash]) %
+ q->numbuckets;
+
+}
+
+static inline u16 prob_plus(u16 p1, u16 p2)
+{
+ return p1 < SFB_MAX_PROB - p2 ? p1 + p2 : SFB_MAX_PROB;
+}
+
+static inline u16 prob_minus(u16 p1, u16 p2)
+{
+ return p1 > p2 ? p1 - p2 : 0;
+}
+
+static void
+increment_one_qlen(struct sk_buff *skb, int filter, struct sfb_sched_data *q)
+{
+ int i;
+ for(i = 0; i < q->numhashes; i++) {
+ unsigned hash = sfb_hash(skb, i, filter, q);
+ if(q->buckets[filter][i][hash].qlen < 0xFFFF)
+ q->buckets[filter][i][hash].qlen++;
+ }
+}
+
+static void
+increment_qlen(struct sk_buff *skb, struct sfb_sched_data *q)
+{
+ increment_one_qlen(skb, q->filter, q);
+ if(q->double_buffering)
+ increment_one_qlen(skb, !q->filter, q);
+}
+
+static void
+decrement_one_qlen(struct sk_buff *skb, int filter, struct sfb_sched_data *q)
+{
+ int i;
+ for(i = 0; i < q->numhashes; i++) {
+ unsigned hash = sfb_hash(skb, i, filter, q);
+ if(q->buckets[filter][i][hash].qlen > 0)
+ q->buckets[filter][i][hash].qlen--;
+ }
+}
+
+static void
+decrement_qlen(struct sk_buff *skb, struct sfb_sched_data *q)
+{
+ decrement_one_qlen(skb, q->filter, q);
+ if(q->double_buffering)
+ decrement_one_qlen(skb, !q->filter, q);
+}
+
+static inline void
+decrement_prob(int filter, int bucket, unsigned hash, struct sfb_sched_data *q)
+{
+ q->buckets[filter][bucket][hash].pm =
+ prob_minus(q->buckets[filter][bucket][hash].pm,
+ q->decrement);
+}
+
+static inline void
+increment_prob(int filter, int bucket, unsigned hash, struct sfb_sched_data *q)
+{
+ q->buckets[filter][bucket][hash].pm =
+ prob_plus(q->buckets[filter][bucket][hash].pm,
+ q->increment);
+}
+
+static void
+zero_all_buckets(int filter, struct sfb_sched_data *q)
+{
+ int i, j;
+ for(i = 0; i < MAXHASHES; i++) {
+ for(j = 0; j < MAXBUCKETS; j++) {
+ q->buckets[filter][i][j].pm = 0;
+ q->buckets[filter][i][j].qlen = 0;
+ }
+ }
+}
+
+static void
+compute_qlen(u16 *qlen_r, u16 *prob_r, struct sfb_sched_data *q)
+{
+ int i, j, filter = q->filter;
+ u16 qlen = 0, prob = 0;
+ for(i = 0; i < q->numhashes; i++) {
+ for(j = 0; j < q->numbuckets; j++) {
+ if(qlen < q->buckets[filter][i][j].qlen)
+ qlen = q->buckets[filter][i][j].qlen;
+ if(qlen < q->buckets[filter][i][j].pm)
+ prob = q->buckets[filter][i][j].pm;
+ }
+ }
+ *qlen_r = qlen;
+ *prob_r = prob;
+}
+
+
+static void
+init_perturbation(int filter, struct sfb_sched_data *q)
+{
+ get_random_bytes(q->perturbation[filter],
+ sizeof(q->perturbation[filter]));
+}
+
+static void
+swap_buffers(struct sfb_sched_data *q)
+{
+ q->filter = !q->filter;
+ zero_all_buckets(!q->filter, q);
+ init_perturbation(!q->filter, q);
+ q->double_buffering = 0;
+}
+
+static int rate_limit(struct sk_buff *skb, psched_time_t now,
+ struct sfb_sched_data* q)
+{
+ if(q->penalty_rate == 0 || q->penalty_burst == 0)
+ return 1;
+
+ if(q->tokens_avail < 1) {
+ psched_tdiff_t age;
+
+ age = psched_tdiff_bounded(now, q->token_time,
+ 256 * PSCHED_TICKS_PER_SEC);
+ q->tokens_avail =
+ (age * q->penalty_rate / PSCHED_TICKS_PER_SEC);
+ if(q->tokens_avail > q->penalty_burst)
+ q->tokens_avail = q->penalty_burst;
+ q->token_time = now;
+ if(q->tokens_avail < 1)
+ return 1;
+ }
+
+ q->tokens_avail--;
+ return 0;
+}
+
+static int sfb_enqueue(struct sk_buff *skb, struct Qdisc* sch)
+{
+
+ struct sfb_sched_data *q = qdisc_priv(sch);
+ struct Qdisc *child = q->qdisc;
+ psched_time_t now;
+ int filter;
+ u16 minprob = SFB_MAX_PROB;
+ u16 minqlen = (u16)(~0);
+ u32 r;
+ int ret, i;
+
+ now = psched_get_time();
+
+ if(q->rehash_interval > 0) {
+ psched_tdiff_t age;
+ age = psched_tdiff_bounded(now, q->rehash_time,
+ q->rehash_interval *
+ PSCHED_TICKS_PER_SEC);
+ if(unlikely(age >= q->rehash_interval * PSCHED_TICKS_PER_SEC)) {
+ swap_buffers(q);
+ q->rehash_time = now;
+ }
+ if(unlikely(!q->double_buffering && q->db_interval > 0 &&
+ age >= (q->rehash_interval - q->db_interval) *
+ PSCHED_TICKS_PER_SEC))
+ q->double_buffering = 1;
+ }
+
+ filter = q->filter;
+
+ for(i = 0; i < q->numhashes; i++) {
+ unsigned hash = sfb_hash(skb, i, filter, q);
+ if(q->buckets[filter][i][hash].qlen == 0)
+ decrement_prob(filter, i, hash, q);
+ else if(unlikely(q->buckets[filter][i][hash].qlen >= q->target))
+ increment_prob(filter, i, hash, q);
+ if(minqlen > q->buckets[filter][i][hash].qlen)
+ minqlen = q->buckets[filter][i][hash].qlen;
+ if(minprob > q->buckets[filter][i][hash].pm)
+ minprob = q->buckets[filter][i][hash].pm;
+ }
+
+ if(q->double_buffering) {
+ for(i = 0; i < q->numhashes; i++) {
+ unsigned hash = sfb_hash(skb, i, !filter, q);
+ if(q->buckets[!filter][i][hash].qlen == 0)
+ decrement_prob(!filter, i, hash, q);
+ else if(unlikely(q->buckets[!filter][i][hash].qlen >=
+ q->target))
+ increment_prob(!filter, i, hash, q);
+ }
+ }
+
+ if(unlikely(minqlen >= q->max || sch->q.qlen >= q->limit)) {
+ sch->qstats.overlimits++;
+ if(likely(minqlen >= q->max))
+ q->bucketdrop++;
+ else
+ q->queuedrop++;
+ goto drop;
+ }
+
+ if(unlikely(minprob >= SFB_MAX_PROB)) {
+ /* Inelastic flow */
+ if(rate_limit(skb, now, q)) {
+ sch->qstats.overlimits++;
+ q->penaltydrop++;
+ goto drop;
+ }
+ goto enqueue;
+ }
+
+ r = net_random() & SFB_MAX_PROB;
+
+ if(unlikely(r < minprob)) {
+ if(unlikely(minprob > SFB_MAX_PROB / 2)) {
+ /* If we're marking that many packets, then either
+ this flow is unresponsive, or we're badly congested.
+ In either case, we want to start dropping packets. */
+ if(r < (minprob - SFB_MAX_PROB / 2) * 2) {
+ q->earlydrop++;
+ goto drop;
+ }
+ }
+ if(INET_ECN_set_ce(skb)) {
+ q->marked++;
+ } else {
+ q->earlydrop++;
+ goto drop;
+ }
+ }
+
+ enqueue:
+ ret = child->enqueue(skb, child);
+ if(likely(ret == NET_XMIT_SUCCESS)) {
+ sch->q.qlen++;
+ increment_qlen(skb, q);
+ sch->bstats.packets++;
+ sch->bstats.bytes += skb->len;
+ sch->qstats.backlog += skb->len;
+ } else {
+ q->queuedrop++;
+ }
+ return ret;
+
+ drop:
+ qdisc_drop(skb, sch);
+ return NET_XMIT_CN;
+}
+
+static int sfb_requeue(struct sk_buff *skb, struct Qdisc* sch)
+{
+ struct sfb_sched_data *q = qdisc_priv(sch);
+ struct Qdisc *child = q->qdisc;
+ int ret;
+
+ ret = child->ops->requeue(skb, child);
+ if(unlikely(ret != NET_XMIT_SUCCESS)) {
+ sch->qstats.drops++;
+ return ret;
+ }
+
+ sch->q.qlen++;
+ increment_qlen(skb, q);
+ sch->qstats.backlog += skb->len;
+ sch->qstats.requeues++;
+ return ret;
+}
+
+static struct sk_buff *sfb_dequeue(struct Qdisc* sch)
+{
+ struct sfb_sched_data *q = qdisc_priv(sch);
+ struct Qdisc *child = q->qdisc;
+ struct sk_buff *skb;
+
+ skb = child->dequeue(q->qdisc);
+
+ if(skb) {
+ sch->q.qlen--;
+ sch->qstats.backlog -= skb->len;
+ decrement_qlen(skb, q);
+ }
+
+ return skb;
+}
+
+static void sfb_reset(struct Qdisc* sch)
+{
+ struct sfb_sched_data *q = qdisc_priv(sch);
+
+ qdisc_reset(q->qdisc);
+ sch->q.qlen = 0;
+ sch->qstats.backlog = 0;
+ q->filter = 0;
+ q->double_buffering = 0;
+ zero_all_buckets(0, q);
+ zero_all_buckets(1, q);
+ init_perturbation(q->filter, q);
+}
+
+static void sfb_destroy(struct Qdisc *sch)
+{
+ struct sfb_sched_data *q = qdisc_priv(sch);
+ qdisc_destroy(q->qdisc);
+ q->qdisc = NULL;
+}
+
+static struct Qdisc *sfb_create_dflt(struct Qdisc *sch, u32 limit)
+{
+ struct Qdisc *q;
+ struct rtattr *rta;
+ int ret;
+
+ q = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops,
+ TC_H_MAKE(sch->handle, 1));
+ if (q) {
+ rta = kmalloc(RTA_LENGTH(sizeof(struct tc_fifo_qopt)),
+ GFP_KERNEL);
+ if (rta) {
+ rta->rta_type = RTM_NEWQDISC;
+ rta->rta_len = RTA_LENGTH(sizeof(struct tc_fifo_qopt));
+ ((struct tc_fifo_qopt *)RTA_DATA(rta))->limit = limit;
+
+ ret = q->ops->change(q, rta);
+ kfree(rta);
+
+ if (ret == 0)
+ return q;
+ }
+ qdisc_destroy(q);
+ }
+ return NULL;
+}
+
+static int sfb_change(struct Qdisc *sch, struct rtattr *opt)
+{
+ struct sfb_sched_data *q = qdisc_priv(sch);
+ struct Qdisc *child = NULL;
+ struct rtattr *tb[TCA_SFB_MAX];
+ struct tc_sfb_qopt *ctl;
+ u16 numhashes, numbuckets, rehash_interval, db_interval;
+ u8 hash_type;
+ u32 limit;
+ u16 max, target;
+ u16 increment, decrement;
+ u32 penalty_rate, penalty_burst;
+
+ if (opt == NULL) {
+ numhashes = 6;
+ numbuckets = 32;
+ hash_type = SFB_HASH_FLOW;
+ rehash_interval = 600;
+ db_interval = 60;
+ limit = 0;
+ max = 25;
+ target = 20;
+ increment = (SFB_MAX_PROB + 1000) / 2000;
+ decrement = (SFB_MAX_PROB + 10000) / 20000;
+ penalty_rate = 10;
+ penalty_burst = 20;
+ } else {
+ if(rtattr_parse_nested(tb, TCA_SFB_MAX, opt))
+ return -EINVAL;
+
+ if (tb[TCA_SFB_PARMS-1] == NULL ||
+ RTA_PAYLOAD(tb[TCA_SFB_PARMS-1]) < sizeof(*ctl))
+ return -EINVAL;
+
+ ctl = RTA_DATA(tb[TCA_SFB_PARMS-1]);
+ numhashes = ctl->numhashes;
+ numbuckets = ctl->numbuckets;
+ rehash_interval = ctl->rehash_interval;
+ db_interval = ctl->db_interval;
+ hash_type = ctl->hash_type;
+ limit = ctl->limit;
+ max = ctl->max;
+ target = ctl->target;
+ increment = ctl->increment;
+ decrement = ctl->decrement;
+ penalty_rate = ctl->penalty_rate;
+ penalty_burst = ctl->penalty_burst;
+ }
+
+ if(numbuckets <= 0 || numbuckets > MAXBUCKETS)
+ numbuckets = MAXBUCKETS;
+ if(numhashes <= 0 || numhashes > MAXHASHES)
+ numhashes = MAXHASHES;
+ if(hash_type >= __SFB_HASH_MAX)
+ hash_type = SFB_HASH_FLOW;
+ if(limit == 0)
+ limit = sch->dev->tx_queue_len ? sch->dev->tx_queue_len : 1;
+
+ child = sfb_create_dflt(sch, limit);
+ if(child == NULL)
+ return -ENOMEM;
+
+ sch_tree_lock(sch);
+ if(child) {
+ qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen);
+ qdisc_destroy(xchg(&q->qdisc, child));
+ }
+
+ q->numhashes = numhashes;
+ q->numbuckets = numbuckets;
+ q->rehash_interval = rehash_interval;
+ q->db_interval = db_interval;
+ q->hash_type = hash_type;
+ q->limit = limit;
+ q->increment = increment;
+ q->decrement = decrement;
+ q->max = max;
+ q->target = target;
+ q->penalty_rate = penalty_rate;
+ q->penalty_burst = penalty_burst;
+
+ q->filter = 0;
+ q->double_buffering = 0;
+ zero_all_buckets(0, q);
+ zero_all_buckets(1, q);
+ init_perturbation(q->filter, q);
+
+ sch_tree_unlock(sch);
+
+ return 0;
+}
+
+static int sfb_init(struct Qdisc *sch, struct rtattr *opt)
+{
+ struct sfb_sched_data *q = qdisc_priv(sch);
+
+ q->qdisc = &noop_qdisc;
+ return sfb_change(sch, opt);
+}
+
+static int sfb_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+ struct sfb_sched_data *q = qdisc_priv(sch);
+ struct rtattr *opts = NULL;
+ struct tc_sfb_qopt opt = { .numhashes = q->numhashes,
+ .numbuckets = q->numbuckets,
+ .rehash_interval = q->rehash_interval,
+ .db_interval = q->db_interval,
+ .hash_type = q->hash_type,
+ .limit = q->limit,
+ .max = q->max,
+ .target = q->target,
+ .increment = q->increment,
+ .decrement = q->decrement,
+ .penalty_rate = q->penalty_rate,
+ .penalty_burst = q->penalty_burst,
+ };
+
+ opts = RTA_NEST(skb, TCA_OPTIONS);
+ RTA_PUT(skb, TCA_SFB_PARMS, sizeof(opt), &opt);
+ return RTA_NEST_END(skb, opts);
+
+rtattr_failure:
+ return -1;
+}
+
+static int sfb_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
+{
+ struct sfb_sched_data *q = qdisc_priv(sch);
+ struct tc_sfb_xstats st = { .earlydrop = q->earlydrop,
+ .penaltydrop = q->penaltydrop,
+ .bucketdrop = q->bucketdrop,
+ .marked = q->marked};
+
+ compute_qlen(&st.maxqlen, &st.maxprob, q);
+
+ return gnet_stats_copy_app(d, &st, sizeof(st));
+}
+
+static int sfb_dump_class(struct Qdisc *sch, unsigned long cl,
+ struct sk_buff *skb, struct tcmsg *tcm)
+{
+ return -ENOSYS;
+}
+
+static int sfb_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
+ struct Qdisc **old)
+{
+ struct sfb_sched_data *q = qdisc_priv(sch);
+
+ if (new == NULL)
+ new = &noop_qdisc;
+
+ sch_tree_lock(sch);
+ *old = xchg(&q->qdisc, new);
+ qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
+ qdisc_reset(*old);
+ sch_tree_unlock(sch);
+ return 0;
+}
+
+static struct Qdisc *sfb_leaf(struct Qdisc *sch, unsigned long arg)
+{
+ struct sfb_sched_data *q = qdisc_priv(sch);
+ return q->qdisc;
+}
+
+static unsigned long sfb_get(struct Qdisc *sch, u32 classid)
+{
+ return 1;
+}
+
+static void sfb_put(struct Qdisc *sch, unsigned long arg)
+{
+ return;
+}
+
+static int sfb_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
+ struct rtattr **tca, unsigned long *arg)
+{
+ return -ENOSYS;
+}
+
+static int sfb_delete(struct Qdisc *sch, unsigned long cl)
+{
+ return -ENOSYS;
+}
+
+static void sfb_walk(struct Qdisc *sch, struct qdisc_walker *walker)
+{
+ if (!walker->stop) {
+ if (walker->count >= walker->skip)
+ if (walker->fn(sch, 1, walker) < 0) {
+ walker->stop = 1;
+ return;
+ }
+ walker->count++;
+ }
+}
+
+static struct tcf_proto **sfb_find_tcf(struct Qdisc *sch, unsigned long cl)
+{
+ return NULL;
+}
+
+static struct Qdisc_class_ops sfb_class_ops =
+{
+ .graft = sfb_graft,
+ .leaf = sfb_leaf,
+ .get = sfb_get,
+ .put = sfb_put,
+ .change = sfb_change_class,
+ .delete = sfb_delete,
+ .walk = sfb_walk,
+ .tcf_chain = sfb_find_tcf,
+ .dump = sfb_dump_class,
+};
+
+struct Qdisc_ops sfb_qdisc_ops = {
+ .id = "sfb",
+ .priv_size = sizeof(struct sfb_sched_data),
+ .cl_ops = &sfb_class_ops,
+ .enqueue = sfb_enqueue,
+ .dequeue = sfb_dequeue,
+ .requeue = sfb_requeue,
+ .init = sfb_init,
+ .reset = sfb_reset,
+ .destroy = sfb_destroy,
+ .change = sfb_change,
+ .dump = sfb_dump,
+ .dump_stats = sfb_dump_stats,
+ .owner = THIS_MODULE,
+};
+
+static int __init sfb_module_init(void)
+{
+ return register_qdisc(&sfb_qdisc_ops);
+}
+
+static void __exit sfb_module_exit(void)
+{
+ unregister_qdisc(&sfb_qdisc_ops);
+}
+
+module_init(sfb_module_init)
+module_exit(sfb_module_exit)
+
+MODULE_DESCRIPTION("Stochastic Fair Blue queue discipline");
+MODULE_AUTHOR("Juliusz Chroboczek");
+MODULE_LICENSE("GPL");
diff -urN empty/sfb.h sch_sfb/sfb.h
--- empty/sfb.h 1970-01-01 01:00:00.000000000 +0100
+++ sch_sfb/sfb.h 2008-04-08 00:28:43.000000000 +0200
@@ -0,0 +1,52 @@
+/*
+ * sfb.h Stochastic Fair Blue
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * Authors: Juliusz Chroboczek <jch@....jussieu.fr>
+ */
+
+#include <linux/types.h>
+
+#define MAXHASHES 12
+#define MAXBUCKETS 32
+
+enum
+{
+ TCA_SFB_UNSPEC,
+ TCA_SFB_PARMS,
+ __TCA_SFB_MAX,
+};
+
+enum {
+ SFB_HASH_FLOW,
+ SFB_HASH_SOURCE,
+ SFB_HASH_DEST,
+ SFB_HASH_SOURCE_DEST,
+ __SFB_HASH_MAX,
+};
+
+#define TCA_SFB_MAX (__TCA_SFB_MAX - 1)
+
+struct tc_sfb_qopt
+{
+ __u8 hash_type, pad;
+ __u16 numhashes, numbuckets;
+ __u16 rehash_interval, db_interval;
+ __u16 max, target;
+ __u16 increment, decrement;
+ __u16 pad2;
+ __u32 limit;
+ __u32 penalty_rate, penalty_burst;
+};
+
+struct tc_sfb_xstats
+{
+ __u32 earlydrop, penaltydrop, bucketdrop, queuedrop, marked;
+ __u16 maxqlen, maxprob;
+};
+
+#define SFB_MAX_PROB 0xFFFF
diff --git a/tc/Makefile b/tc/Makefile
index 0facc88..2e7cddb 100644
--- a/tc/Makefile
+++ b/tc/Makefile
@@ -13,6 +13,7 @@ TCMODULES += q_tbf.o
TCMODULES += q_cbq.o
TCMODULES += q_rr.o
TCMODULES += q_netem.o
+TCMODULES += q_sfb.o
TCMODULES += f_rsvp.o
TCMODULES += f_u32.o
TCMODULES += f_route.o
diff --git a/tc/q_sfb.c b/tc/q_sfb.c
new file mode 100644
index 0000000..41512db
--- /dev/null
+++ b/tc/q_sfb.c
@@ -0,0 +1,252 @@
+/*
+ * q_red.c Stochastic Fair Blue.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * Authors: Juliusz Chroboczek <jch@....jussieu.fr>
+ *
+ */
+
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <syslog.h>
+#include <fcntl.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <string.h>
+
+#include "utils.h"
+#include "tc_util.h"
+
+#include "sfb.h"
+
+static void explain(void)
+{
+ fprintf(stderr,
+ "Usage: ... sfb "
+ "hashes N buckets N hash-type TYPE rehash SECS db SECS\n"
+ " limit PACKETS max PACKETS target PACKETS\n"
+ " increment FLOAT decrement FLOAT\n"
+ " penalty_rate PPS penalty_burst PACKETS\n");
+}
+
+static int get_prob(__u16 *val, const char *arg)
+{
+ double d;
+ char *ptr;
+
+ if(!arg || !*arg)
+ return -1;
+ d = strtod(arg, &ptr);
+ if(!ptr || ptr == arg || d < 0.0 || d > 1.0)
+ return -1;
+ *val = (__u16)(d * SFB_MAX_PROB + 0.5);
+ return 0;
+}
+
+static char *
+hash_type(__u8 val)
+{
+ switch(val) {
+ case SFB_HASH_FLOW: return "flow";
+ case SFB_HASH_SOURCE: return "source";
+ case SFB_HASH_DEST: return "dest";
+ case SFB_HASH_SOURCE_DEST: return "source-dest";
+ default: return "???";
+ }
+}
+
+static int get_hash_type(__u8 *val, const char *arg)
+{
+ if(strcmp(arg, "flow") == 0)
+ *val = SFB_HASH_FLOW;
+ else if(strcmp(arg, "source") == 0)
+ *val = SFB_HASH_SOURCE;
+ else if(strcmp(arg, "dest") == 0)
+ *val = SFB_HASH_DEST;
+ else if(strcmp(arg, "source-dest") == 0)
+ *val = SFB_HASH_SOURCE_DEST;
+ else
+ return -1;
+
+ return 0;
+}
+
+static int sfb_parse_opt(struct qdisc_util *qu, int argc, char **argv,
+ struct nlmsghdr *n)
+{
+ struct tc_sfb_qopt opt;
+ struct rtattr *tail;
+
+ memset(&opt, 0, sizeof(opt));
+ opt.numhashes = 6;
+ opt.numbuckets = 32;
+ opt.rehash_interval = 600;
+ opt.db_interval = 60;
+ opt.penalty_rate = 10;
+ opt.penalty_burst = 20;
+ opt.increment = (SFB_MAX_PROB + 1000) / 2000;
+ opt.decrement = (SFB_MAX_PROB + 10000) / 20000;
+
+ while (argc > 0) {
+ if (strcmp(*argv, "hashes") == 0) {
+ NEXT_ARG();
+ if (get_u16(&opt.numhashes, *argv, 0)) {
+ fprintf(stderr, "Illegal \"hashes\"\n");
+ return -1;
+ }
+ } else if (strcmp(*argv, "buckets") == 0) {
+ NEXT_ARG();
+ if (get_u16(&opt.numbuckets, *argv, 0)) {
+ fprintf(stderr, "Illegal \"buckets\"\n");
+ return -1;
+ }
+ } else if (strcmp(*argv, "hash-type") == 0) {
+ NEXT_ARG();
+ if (get_hash_type(&opt.hash_type, *argv)) {
+ fprintf(stderr, "Illegal \"hash-type\"\n");
+ return -1;
+ }
+ } else if (strcmp(*argv, "rehash") == 0) {
+ NEXT_ARG();
+ if (get_u16(&opt.rehash_interval, *argv, 0)) {
+ fprintf(stderr, "Illegal \"rehash\"\n");
+ return -1;
+ }
+ } else if (strcmp(*argv, "db") == 0) {
+ NEXT_ARG();
+ if (get_u16(&opt.db_interval, *argv, 0)) {
+ fprintf(stderr, "Illegal \"db\"\n");
+ return -1;
+ }
+ } else if (strcmp(*argv, "limit") == 0) {
+ NEXT_ARG();
+ if (get_u32(&opt.limit, *argv, 0)) {
+ fprintf(stderr, "Illegal \"limit\"\n");
+ return -1;
+ }
+ } else if (strcmp(*argv, "max") == 0) {
+ NEXT_ARG();
+ if (get_u16(&opt.max, *argv, 0)) {
+ fprintf(stderr, "Illegal \"max\"\n");
+ return -1;
+ }
+ } else if (strcmp(*argv, "target") == 0) {
+ NEXT_ARG();
+ if (get_u16(&opt.target, *argv, 0)) {
+ fprintf(stderr, "Illegal \"target\"\n");
+ return -1;
+ }
+ } else if (strcmp(*argv, "increment") == 0) {
+ NEXT_ARG();
+ if (get_prob(&opt.increment, *argv)) {
+ fprintf(stderr, "Illegal \"increment\"\n");
+ return -1;
+ }
+ } else if (strcmp(*argv, "decrement") == 0) {
+ NEXT_ARG();
+ if (get_prob(&opt.decrement, *argv)) {
+ fprintf(stderr, "Illegal \"decrement\"\n");
+ return -1;
+ }
+ } else if (strcmp(*argv, "penalty_rate") == 0) {
+ NEXT_ARG();
+ if (get_u32(&opt.penalty_rate, *argv, 0)) {
+ fprintf(stderr, "Illegal \"penalty_rate\"\n");
+ return -1;
+ }
+ } else if (strcmp(*argv, "penalty_burst") == 0) {
+ NEXT_ARG();
+ if (get_u32(&opt.penalty_burst, *argv, 0)) {
+ fprintf(stderr, "Illegal \"penalty_burst\"\n");
+ return -1;
+ }
+ } else {
+ fprintf(stderr, "What is \"%s\"?\n", *argv);
+ explain();
+ return -1;
+ }
+ argc--; argv++;
+ }
+
+ if(opt.max == 0) {
+ if(opt.target >= 1)
+ opt.max = (opt.target * 5 + 1) / 4;
+ else
+ opt.max = 25;
+ }
+ if(opt.target == 0)
+ opt.target = (opt.max * 4 + 3) / 5;
+
+ tail = NLMSG_TAIL(n);
+ addattr_l(n, 1024, TCA_OPTIONS, NULL, 0);
+ addattr_l(n, 1024, TCA_SFB_PARMS, &opt, sizeof(opt));
+ tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
+ return 0;
+}
+
+static int sfb_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
+{
+ struct rtattr *tb[__TCA_SFB_MAX];
+ struct tc_sfb_qopt *qopt;
+
+ if(opt == NULL)
+ return 0;
+
+ parse_rtattr_nested(tb, TCA_SFB_MAX, opt);
+ if(tb[TCA_SFB_PARMS] == NULL)
+ return -1;
+ qopt = RTA_DATA(tb[TCA_SFB_PARMS]);
+ if(RTA_PAYLOAD(tb[TCA_SFB_PARMS]) < sizeof(*qopt))
+ return -1;
+
+ fprintf(f,
+ "hash %s limit %d max %d target %d\n"
+ " increment %.5f decrement %.5f penalty rate %d burst %d "
+ "(%ds %ds %dx%d)",
+ hash_type(qopt->hash_type),
+ qopt->limit, qopt->max, qopt->target,
+ (double)qopt->increment / SFB_MAX_PROB,
+ (double)qopt->decrement / SFB_MAX_PROB,
+ qopt->penalty_rate, qopt->penalty_burst,
+ qopt->rehash_interval, qopt->db_interval,
+ qopt->numhashes, qopt->numbuckets);
+
+ return 0;
+}
+
+static int sfb_print_xstats(struct qdisc_util *qu, FILE *f,
+ struct rtattr *xstats)
+{
+ struct tc_sfb_xstats *st;
+
+ if(xstats == NULL)
+ return 0;
+
+ if(RTA_PAYLOAD(xstats) < sizeof(*st))
+ return -1;
+
+ st = RTA_DATA(xstats);
+ fprintf(f,
+ " earlydrop %u penaltydrop %u bucketdrop %u queuedrop %u marked %u\n"
+ " maxqlen %u maxprob %.5f",
+ st->earlydrop, st->penaltydrop, st->bucketdrop, st->queuedrop,
+ st->marked,
+ st->maxqlen, (double)st->maxprob / SFB_MAX_PROB);
+
+ return 0;
+}
+
+struct qdisc_util sfb_qdisc_util = {
+ .id = "sfb",
+ .parse_qopt = sfb_parse_opt,
+ .print_qopt = sfb_print_opt,
+ .print_xstats = sfb_print_xstats,
+};
--
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