echo "loads. The output is the goodput in Mbps (unless -D was used)."
echo ""
echo "USAGE: $name [out] [-b=<prog>|--bpf=<prog>] [-c=<cc>|--cc=<cc>]"
- echo " [-D] [-d=<delay>|--delay=<delay>] [--debug] [-E]"
+ echo " [-D] [-d=<delay>|--delay=<delay>] [--debug] [-E] [--edt]"
echo " [-f=<#flows>|--flows=<#flows>] [-h] [-i=<id>|--id=<id >]"
echo " [-l] [-N] [--no_cn] [-p=<port>|--port=<port>] [-P]"
echo " [-q=<qdisc>] [-R] [-s=<server>|--server=<server]"
echo " other detailed information. This information is"
echo " test dependent (i.e. iperf3 or netperf)."
echo " -E enable ECN (not required for dctcp)"
+ echo " --edt use fq's Earliest Departure Time (requires fq)"
echo " -f or --flows number of concurrent flows (default=1)"
echo " -i or --id cgroup id (an integer, default is 1)"
echo " -N use netperf instead of iperf3"
details=1
;;
-E)
- ecn=1
+ ecn=1
+ ;;
+ --edt)
+ flags="$flags --edt"
+ qdisc="fq"
;;
- # Support for upcomming fq Early Departure Time egress rate limiting
- #--edt)
- # prog="hbm_out_edt_kern.o"
- # qdisc="fq"
- # ;;
-f=*|--flows=*)
flows="${i#*=}"
;;
tc qdisc del dev lo root > /dev/null 2>&1
tc qdisc add dev lo root netem delay $netem\ms > /dev/null 2>&1
elif [ "$qdisc" != "" ] ; then
- tc qdisc del dev lo root > /dev/null 2>&1
- tc qdisc add dev lo root $qdisc > /dev/null 2>&1
+ tc qdisc del dev eth0 root > /dev/null 2>&1
+ tc qdisc add dev eth0 root $qdisc > /dev/null 2>&1
fi
n=0
if [ "$netem" -ne "0" ] ; then
tc qdisc del dev lo root > /dev/null 2>&1
fi
-
+if [ "$qdisc" != "" ] ; then
+ tc qdisc del dev eth0 root > /dev/null 2>&1
+fi
sleep 2
hbmPid=`ps ax | grep "hbm " | grep --invert-match "grep" | awk '{ print $1 }'`
bool debugFlag;
bool work_conserving_flag;
bool no_cn_flag;
+bool edt_flag;
static void Usage(void);
static void read_trace_pipe2(void);
fprintf(fout, "avg rtt:%d\n",
(int)(qstats.sum_rtt / (qstats.pkts_total + 1)));
// Average credit
- fprintf(fout, "avg credit:%d\n",
- (int)(qstats.sum_credit /
- (1500 * ((int)qstats.pkts_total) + 1)));
+ if (edt_flag)
+ fprintf(fout, "avg credit_ms:%.03f\n",
+ (qstats.sum_credit /
+ (qstats.pkts_total + 1.0)) / 1000000.0);
+ else
+ fprintf(fout, "avg credit:%d\n",
+ (int)(qstats.sum_credit /
+ (1500 * ((int)qstats.pkts_total ) + 1)));
// Return values stats
for (k = 0; k < RET_VAL_COUNT; k++) {
" Where:\n"
" -o indicates egress direction (default)\n"
" -d print BPF trace debug buffer\n"
+ " --edt use fq's Earliest Departure Time\n"
" -l also limit flows using loopback\n"
" -n <#> to create cgroup \"/hbm#\" and attach prog\n"
" Default is /hbm1\n"
char *optstring = "iodln:r:st:wh";
struct option loptions[] = {
{"no_cn", 0, NULL, 1},
+ {"edt", 0, NULL, 2},
{NULL, 0, NULL, 0}
};
case 1:
no_cn_flag = true;
break;
+ case 2:
+ prog = "hbm_edt_kern.o";
+ edt_flag = true;
+ break;
case'o':
break;
case 'd':
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2019 Facebook
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * Sample Host Bandwidth Manager (HBM) BPF program.
+ *
+ * A cgroup skb BPF egress program to limit cgroup output bandwidth.
+ * It uses a modified virtual token bucket queue to limit average
+ * egress bandwidth. The implementation uses credits instead of tokens.
+ * Negative credits imply that queueing would have happened (this is
+ * a virtual queue, so no queueing is done by it. However, queueing may
+ * occur at the actual qdisc (which is not used for rate limiting).
+ *
+ * This implementation uses 3 thresholds, one to start marking packets and
+ * the other two to drop packets:
+ * CREDIT
+ * - <--------------------------|------------------------> +
+ * | | | 0
+ * | Large pkt |
+ * | drop thresh |
+ * Small pkt drop Mark threshold
+ * thresh
+ *
+ * The effect of marking depends on the type of packet:
+ * a) If the packet is ECN enabled and it is a TCP packet, then the packet
+ * is ECN marked.
+ * b) If the packet is a TCP packet, then we probabilistically call tcp_cwr
+ * to reduce the congestion window. The current implementation uses a linear
+ * distribution (0% probability at marking threshold, 100% probability
+ * at drop threshold).
+ * c) If the packet is not a TCP packet, then it is dropped.
+ *
+ * If the credit is below the drop threshold, the packet is dropped. If it
+ * is a TCP packet, then it also calls tcp_cwr since packets dropped by
+ * by a cgroup skb BPF program do not automatically trigger a call to
+ * tcp_cwr in the current kernel code.
+ *
+ * This BPF program actually uses 2 drop thresholds, one threshold
+ * for larger packets (>= 120 bytes) and another for smaller packets. This
+ * protects smaller packets such as SYNs, ACKs, etc.
+ *
+ * The default bandwidth limit is set at 1Gbps but this can be changed by
+ * a user program through a shared BPF map. In addition, by default this BPF
+ * program does not limit connections using loopback. This behavior can be
+ * overwritten by the user program. There is also an option to calculate
+ * some statistics, such as percent of packets marked or dropped, which
+ * a user program, such as hbm, can access.
+ */
+
+#include "hbm_kern.h"
+
+SEC("cgroup_skb/egress")
+int _hbm_out_cg(struct __sk_buff *skb)
+{
+ long long delta = 0, delta_send;
+ unsigned long long curtime, sendtime;
+ struct hbm_queue_stats *qsp = NULL;
+ unsigned int queue_index = 0;
+ bool congestion_flag = false;
+ bool ecn_ce_flag = false;
+ struct hbm_pkt_info pkti = {};
+ struct hbm_vqueue *qdp;
+ bool drop_flag = false;
+ bool cwr_flag = false;
+ int len = skb->len;
+ int rv = ALLOW_PKT;
+
+ qsp = bpf_map_lookup_elem(&queue_stats, &queue_index);
+
+ // Check if we should ignore loopback traffic
+ if (qsp != NULL && !qsp->loopback && (skb->ifindex == 1))
+ return ALLOW_PKT;
+
+ hbm_get_pkt_info(skb, &pkti);
+
+ // We may want to account for the length of headers in len
+ // calculation, like ETH header + overhead, specially if it
+ // is a gso packet. But I am not doing it right now.
+
+ qdp = bpf_get_local_storage(&queue_state, 0);
+ if (!qdp)
+ return ALLOW_PKT;
+ if (qdp->lasttime == 0)
+ hbm_init_edt_vqueue(qdp, 1024);
+
+ curtime = bpf_ktime_get_ns();
+
+ // Begin critical section
+ bpf_spin_lock(&qdp->lock);
+ delta = qdp->lasttime - curtime;
+ // bound bursts to 100us
+ if (delta < -BURST_SIZE_NS) {
+ // negative delta is a credit that allows bursts
+ qdp->lasttime = curtime - BURST_SIZE_NS;
+ delta = -BURST_SIZE_NS;
+ }
+ sendtime = qdp->lasttime;
+ delta_send = BYTES_TO_NS(len, qdp->rate);
+ __sync_add_and_fetch(&(qdp->lasttime), delta_send);
+ bpf_spin_unlock(&qdp->lock);
+ // End critical section
+
+ // Set EDT of packet
+ skb->tstamp = sendtime;
+
+ // Check if we should update rate
+ if (qsp != NULL && (qsp->rate * 128) != qdp->rate)
+ qdp->rate = qsp->rate * 128;
+
+ // Set flags (drop, congestion, cwr)
+ // last packet will be sent in the future, bound latency
+ if (delta > DROP_THRESH_NS || (delta > LARGE_PKT_DROP_THRESH_NS &&
+ len > LARGE_PKT_THRESH)) {
+ drop_flag = true;
+ if (pkti.is_tcp && pkti.ecn == 0)
+ cwr_flag = true;
+ } else if (delta > MARK_THRESH_NS) {
+ if (pkti.is_tcp)
+ congestion_flag = true;
+ else
+ drop_flag = true;
+ }
+
+ if (congestion_flag) {
+ if (bpf_skb_ecn_set_ce(skb)) {
+ ecn_ce_flag = true;
+ } else {
+ if (pkti.is_tcp) {
+ unsigned int rand = bpf_get_prandom_u32();
+
+ if (delta >= MARK_THRESH_NS +
+ (rand % MARK_REGION_SIZE_NS)) {
+ // Do congestion control
+ cwr_flag = true;
+ }
+ } else if (len > LARGE_PKT_THRESH) {
+ // Problem if too many small packets?
+ drop_flag = true;
+ congestion_flag = false;
+ }
+ }
+ }
+
+ if (pkti.is_tcp && drop_flag && pkti.packets_out <= 1) {
+ drop_flag = false;
+ cwr_flag = true;
+ congestion_flag = false;
+ }
+
+ if (qsp != NULL && qsp->no_cn)
+ cwr_flag = false;
+
+ hbm_update_stats(qsp, len, curtime, congestion_flag, drop_flag,
+ cwr_flag, ecn_ce_flag, &pkti, (int) delta);
+
+ if (drop_flag) {
+ __sync_add_and_fetch(&(qdp->lasttime), -delta_send);
+ rv = DROP_PKT;
+ }
+
+ if (cwr_flag)
+ rv |= CWR;
+ return rv;
+}
+char _license[] SEC("license") = "GPL";
#define DROP_PKT 0
#define ALLOW_PKT 1
#define TCP_ECN_OK 1
+#define CWR 2
#ifndef HBM_DEBUG // Define HBM_DEBUG to enable debugging
#undef bpf_printk
#define MAX_CREDIT (100 * MAX_BYTES_PER_PACKET)
#define INIT_CREDIT (INITIAL_CREDIT_PACKETS * MAX_BYTES_PER_PACKET)
+// Time base accounting for fq's EDT
+#define BURST_SIZE_NS 100000 // 100us
+#define MARK_THRESH_NS 50000 // 50us
+#define DROP_THRESH_NS 500000 // 500us
+// Reserve 20us of queuing for small packets (less than 120 bytes)
+#define LARGE_PKT_DROP_THRESH_NS (DROP_THRESH_NS - 20000)
+#define MARK_REGION_SIZE_NS (LARGE_PKT_DROP_THRESH_NS - MARK_THRESH_NS)
+
// rate in bytes per ns << 20
#define CREDIT_PER_NS(delta, rate) ((((u64)(delta)) * (rate)) >> 20)
+#define BYTES_PER_NS(delta, rate) ((((u64)(delta)) * (rate)) >> 20)
+#define BYTES_TO_NS(bytes, rate) div64_u64(((u64)(bytes)) << 20, (u64)(rate))
struct bpf_map_def SEC("maps") queue_state = {
.type = BPF_MAP_TYPE_CGROUP_STORAGE,
struct hbm_pkt_info {
int cwnd;
int rtt;
+ int packets_out;
bool is_ip;
bool is_tcp;
short ecn;
if (tp) {
pkti->cwnd = tp->snd_cwnd;
pkti->rtt = tp->srtt_us >> 3;
+ pkti->packets_out = tp->packets_out;
return 0;
}
}
}
}
+ pkti->cwnd = 0;
+ pkti->rtt = 0;
+ pkti->packets_out = 0;
return 1;
}
-static __always_inline void hbm_get_pkt_info(struct __sk_buff *skb,
- struct hbm_pkt_info *pkti)
+static void hbm_get_pkt_info(struct __sk_buff *skb,
+ struct hbm_pkt_info *pkti)
{
struct iphdr iph;
struct ipv6hdr *ip6h;
static __always_inline void hbm_init_vqueue(struct hbm_vqueue *qdp, int rate)
{
- bpf_printk("Initializing queue_state, rate:%d\n", rate * 128);
- qdp->lasttime = bpf_ktime_get_ns();
- qdp->credit = INIT_CREDIT;
- qdp->rate = rate * 128;
+ bpf_printk("Initializing queue_state, rate:%d\n", rate * 128);
+ qdp->lasttime = bpf_ktime_get_ns();
+ qdp->credit = INIT_CREDIT;
+ qdp->rate = rate * 128;
+}
+
+static __always_inline void hbm_init_edt_vqueue(struct hbm_vqueue *qdp,
+ int rate)
+{
+ unsigned long long curtime;
+
+ curtime = bpf_ktime_get_ns();
+ bpf_printk("Initializing queue_state, rate:%d\n", rate * 128);
+ qdp->lasttime = curtime - BURST_SIZE_NS; // support initial burst
+ qdp->credit = 0; // not used
+ qdp->rate = rate * 128;
}
static __always_inline void hbm_update_stats(struct hbm_queue_stats *qsp,
projects / mirror_ubuntu-kernels.git / commitdiff