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authorLinus Torvalds <torvalds@linux-foundation.org>2020-01-28 16:02:33 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-01-28 16:02:33 -0800
commitbd2463ac7d7ec51d432f23bf0e893fb371a908cd (patch)
tree3da32c23be83adb9d9bda7e51b51fa39f69f2447 /tools/testing/selftests/bpf/progs/bpf_cubic.c
parentMerge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 (diff)
parentnet: phy: add default ARCH_BCM_IPROC for MDIO_BCM_IPROC (diff)
downloadlinux-bd2463ac7d7ec51d432f23bf0e893fb371a908cd.tar.xz
linux-bd2463ac7d7ec51d432f23bf0e893fb371a908cd.zip
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from David Miller: 1) Add WireGuard 2) Add HE and TWT support to ath11k driver, from John Crispin. 3) Add ESP in TCP encapsulation support, from Sabrina Dubroca. 4) Add variable window congestion control to TIPC, from Jon Maloy. 5) Add BCM84881 PHY driver, from Russell King. 6) Start adding netlink support for ethtool operations, from Michal Kubecek. 7) Add XDP drop and TX action support to ena driver, from Sameeh Jubran. 8) Add new ipv4 route notifications so that mlxsw driver does not have to handle identical routes itself. From Ido Schimmel. 9) Add BPF dynamic program extensions, from Alexei Starovoitov. 10) Support RX and TX timestamping in igc, from Vinicius Costa Gomes. 11) Add support for macsec HW offloading, from Antoine Tenart. 12) Add initial support for MPTCP protocol, from Christoph Paasch, Matthieu Baerts, Florian Westphal, Peter Krystad, and many others. 13) Add Octeontx2 PF support, from Sunil Goutham, Geetha sowjanya, Linu Cherian, and others. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1469 commits) net: phy: add default ARCH_BCM_IPROC for MDIO_BCM_IPROC udp: segment looped gso packets correctly netem: change mailing list qed: FW 8.42.2.0 debug features qed: rt init valid initialization changed qed: Debug feature: ilt and mdump qed: FW 8.42.2.0 Add fw overlay feature qed: FW 8.42.2.0 HSI changes qed: FW 8.42.2.0 iscsi/fcoe changes qed: Add abstraction for different hsi values per chip qed: FW 8.42.2.0 Additional ll2 type qed: Use dmae to write to widebus registers in fw_funcs qed: FW 8.42.2.0 Parser offsets modified qed: FW 8.42.2.0 Queue Manager changes qed: FW 8.42.2.0 Expose new registers and change windows qed: FW 8.42.2.0 Internal ram offsets modifications MAINTAINERS: Add entry for Marvell OcteonTX2 Physical Function driver Documentation: net: octeontx2: Add RVU HW and drivers overview octeontx2-pf: ethtool RSS config support octeontx2-pf: Add basic ethtool support ...
Diffstat (limited to 'tools/testing/selftests/bpf/progs/bpf_cubic.c')
-rw-r--r--tools/testing/selftests/bpf/progs/bpf_cubic.c544
1 files changed, 544 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/bpf_cubic.c b/tools/testing/selftests/bpf/progs/bpf_cubic.c
new file mode 100644
index 000000000000..7897c8f4d363
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/bpf_cubic.c
@@ -0,0 +1,544 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/* WARNING: This implemenation is not necessarily the same
+ * as the tcp_cubic.c. The purpose is mainly for testing
+ * the kernel BPF logic.
+ *
+ * Highlights:
+ * 1. CONFIG_HZ .kconfig map is used.
+ * 2. In bictcp_update(), calculation is changed to use usec
+ * resolution (i.e. USEC_PER_JIFFY) instead of using jiffies.
+ * Thus, usecs_to_jiffies() is not used in the bpf_cubic.c.
+ * 3. In bitctcp_update() [under tcp_friendliness], the original
+ * "while (ca->ack_cnt > delta)" loop is changed to the equivalent
+ * "ca->ack_cnt / delta" operation.
+ */
+
+#include <linux/bpf.h>
+#include "bpf_tcp_helpers.h"
+
+char _license[] SEC("license") = "GPL";
+
+#define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
+
+#define BICTCP_BETA_SCALE 1024 /* Scale factor beta calculation
+ * max_cwnd = snd_cwnd * beta
+ */
+#define BICTCP_HZ 10 /* BIC HZ 2^10 = 1024 */
+
+/* Two methods of hybrid slow start */
+#define HYSTART_ACK_TRAIN 0x1
+#define HYSTART_DELAY 0x2
+
+/* Number of delay samples for detecting the increase of delay */
+#define HYSTART_MIN_SAMPLES 8
+#define HYSTART_DELAY_MIN (4000U) /* 4ms */
+#define HYSTART_DELAY_MAX (16000U) /* 16 ms */
+#define HYSTART_DELAY_THRESH(x) clamp(x, HYSTART_DELAY_MIN, HYSTART_DELAY_MAX)
+
+static int fast_convergence = 1;
+static const int beta = 717; /* = 717/1024 (BICTCP_BETA_SCALE) */
+static int initial_ssthresh;
+static const int bic_scale = 41;
+static int tcp_friendliness = 1;
+
+static int hystart = 1;
+static int hystart_detect = HYSTART_ACK_TRAIN | HYSTART_DELAY;
+static int hystart_low_window = 16;
+static int hystart_ack_delta_us = 2000;
+
+static const __u32 cube_rtt_scale = (bic_scale * 10); /* 1024*c/rtt */
+static const __u32 beta_scale = 8*(BICTCP_BETA_SCALE+beta) / 3
+ / (BICTCP_BETA_SCALE - beta);
+/* calculate the "K" for (wmax-cwnd) = c/rtt * K^3
+ * so K = cubic_root( (wmax-cwnd)*rtt/c )
+ * the unit of K is bictcp_HZ=2^10, not HZ
+ *
+ * c = bic_scale >> 10
+ * rtt = 100ms
+ *
+ * the following code has been designed and tested for
+ * cwnd < 1 million packets
+ * RTT < 100 seconds
+ * HZ < 1,000,00 (corresponding to 10 nano-second)
+ */
+
+/* 1/c * 2^2*bictcp_HZ * srtt, 2^40 */
+static const __u64 cube_factor = (__u64)(1ull << (10+3*BICTCP_HZ))
+ / (bic_scale * 10);
+
+/* BIC TCP Parameters */
+struct bictcp {
+ __u32 cnt; /* increase cwnd by 1 after ACKs */
+ __u32 last_max_cwnd; /* last maximum snd_cwnd */
+ __u32 last_cwnd; /* the last snd_cwnd */
+ __u32 last_time; /* time when updated last_cwnd */
+ __u32 bic_origin_point;/* origin point of bic function */
+ __u32 bic_K; /* time to origin point
+ from the beginning of the current epoch */
+ __u32 delay_min; /* min delay (usec) */
+ __u32 epoch_start; /* beginning of an epoch */
+ __u32 ack_cnt; /* number of acks */
+ __u32 tcp_cwnd; /* estimated tcp cwnd */
+ __u16 unused;
+ __u8 sample_cnt; /* number of samples to decide curr_rtt */
+ __u8 found; /* the exit point is found? */
+ __u32 round_start; /* beginning of each round */
+ __u32 end_seq; /* end_seq of the round */
+ __u32 last_ack; /* last time when the ACK spacing is close */
+ __u32 curr_rtt; /* the minimum rtt of current round */
+};
+
+static inline void bictcp_reset(struct bictcp *ca)
+{
+ ca->cnt = 0;
+ ca->last_max_cwnd = 0;
+ ca->last_cwnd = 0;
+ ca->last_time = 0;
+ ca->bic_origin_point = 0;
+ ca->bic_K = 0;
+ ca->delay_min = 0;
+ ca->epoch_start = 0;
+ ca->ack_cnt = 0;
+ ca->tcp_cwnd = 0;
+ ca->found = 0;
+}
+
+extern unsigned long CONFIG_HZ __kconfig;
+#define HZ CONFIG_HZ
+#define USEC_PER_MSEC 1000UL
+#define USEC_PER_SEC 1000000UL
+#define USEC_PER_JIFFY (USEC_PER_SEC / HZ)
+
+static __always_inline __u64 div64_u64(__u64 dividend, __u64 divisor)
+{
+ return dividend / divisor;
+}
+
+#define div64_ul div64_u64
+
+#define BITS_PER_U64 (sizeof(__u64) * 8)
+static __always_inline int fls64(__u64 x)
+{
+ int num = BITS_PER_U64 - 1;
+
+ if (x == 0)
+ return 0;
+
+ if (!(x & (~0ull << (BITS_PER_U64-32)))) {
+ num -= 32;
+ x <<= 32;
+ }
+ if (!(x & (~0ull << (BITS_PER_U64-16)))) {
+ num -= 16;
+ x <<= 16;
+ }
+ if (!(x & (~0ull << (BITS_PER_U64-8)))) {
+ num -= 8;
+ x <<= 8;
+ }
+ if (!(x & (~0ull << (BITS_PER_U64-4)))) {
+ num -= 4;
+ x <<= 4;
+ }
+ if (!(x & (~0ull << (BITS_PER_U64-2)))) {
+ num -= 2;
+ x <<= 2;
+ }
+ if (!(x & (~0ull << (BITS_PER_U64-1))))
+ num -= 1;
+
+ return num + 1;
+}
+
+static __always_inline __u32 bictcp_clock_us(const struct sock *sk)
+{
+ return tcp_sk(sk)->tcp_mstamp;
+}
+
+static __always_inline void bictcp_hystart_reset(struct sock *sk)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct bictcp *ca = inet_csk_ca(sk);
+
+ ca->round_start = ca->last_ack = bictcp_clock_us(sk);
+ ca->end_seq = tp->snd_nxt;
+ ca->curr_rtt = ~0U;
+ ca->sample_cnt = 0;
+}
+
+/* "struct_ops/" prefix is not a requirement
+ * It will be recognized as BPF_PROG_TYPE_STRUCT_OPS
+ * as long as it is used in one of the func ptr
+ * under SEC(".struct_ops").
+ */
+SEC("struct_ops/bictcp_init")
+void BPF_PROG(bictcp_init, struct sock *sk)
+{
+ struct bictcp *ca = inet_csk_ca(sk);
+
+ bictcp_reset(ca);
+
+ if (hystart)
+ bictcp_hystart_reset(sk);
+
+ if (!hystart && initial_ssthresh)
+ tcp_sk(sk)->snd_ssthresh = initial_ssthresh;
+}
+
+/* No prefix in SEC will also work.
+ * The remaining tcp-cubic functions have an easier way.
+ */
+SEC("no-sec-prefix-bictcp_cwnd_event")
+void BPF_PROG(bictcp_cwnd_event, struct sock *sk, enum tcp_ca_event event)
+{
+ if (event == CA_EVENT_TX_START) {
+ struct bictcp *ca = inet_csk_ca(sk);
+ __u32 now = tcp_jiffies32;
+ __s32 delta;
+
+ delta = now - tcp_sk(sk)->lsndtime;
+
+ /* We were application limited (idle) for a while.
+ * Shift epoch_start to keep cwnd growth to cubic curve.
+ */
+ if (ca->epoch_start && delta > 0) {
+ ca->epoch_start += delta;
+ if (after(ca->epoch_start, now))
+ ca->epoch_start = now;
+ }
+ return;
+ }
+}
+
+/*
+ * cbrt(x) MSB values for x MSB values in [0..63].
+ * Precomputed then refined by hand - Willy Tarreau
+ *
+ * For x in [0..63],
+ * v = cbrt(x << 18) - 1
+ * cbrt(x) = (v[x] + 10) >> 6
+ */
+static const __u8 v[] = {
+ /* 0x00 */ 0, 54, 54, 54, 118, 118, 118, 118,
+ /* 0x08 */ 123, 129, 134, 138, 143, 147, 151, 156,
+ /* 0x10 */ 157, 161, 164, 168, 170, 173, 176, 179,
+ /* 0x18 */ 181, 185, 187, 190, 192, 194, 197, 199,
+ /* 0x20 */ 200, 202, 204, 206, 209, 211, 213, 215,
+ /* 0x28 */ 217, 219, 221, 222, 224, 225, 227, 229,
+ /* 0x30 */ 231, 232, 234, 236, 237, 239, 240, 242,
+ /* 0x38 */ 244, 245, 246, 248, 250, 251, 252, 254,
+};
+
+/* calculate the cubic root of x using a table lookup followed by one
+ * Newton-Raphson iteration.
+ * Avg err ~= 0.195%
+ */
+static __always_inline __u32 cubic_root(__u64 a)
+{
+ __u32 x, b, shift;
+
+ if (a < 64) {
+ /* a in [0..63] */
+ return ((__u32)v[(__u32)a] + 35) >> 6;
+ }
+
+ b = fls64(a);
+ b = ((b * 84) >> 8) - 1;
+ shift = (a >> (b * 3));
+
+ /* it is needed for verifier's bound check on v */
+ if (shift >= 64)
+ return 0;
+
+ x = ((__u32)(((__u32)v[shift] + 10) << b)) >> 6;
+
+ /*
+ * Newton-Raphson iteration
+ * 2
+ * x = ( 2 * x + a / x ) / 3
+ * k+1 k k
+ */
+ x = (2 * x + (__u32)div64_u64(a, (__u64)x * (__u64)(x - 1)));
+ x = ((x * 341) >> 10);
+ return x;
+}
+
+/*
+ * Compute congestion window to use.
+ */
+static __always_inline void bictcp_update(struct bictcp *ca, __u32 cwnd,
+ __u32 acked)
+{
+ __u32 delta, bic_target, max_cnt;
+ __u64 offs, t;
+
+ ca->ack_cnt += acked; /* count the number of ACKed packets */
+
+ if (ca->last_cwnd == cwnd &&
+ (__s32)(tcp_jiffies32 - ca->last_time) <= HZ / 32)
+ return;
+
+ /* The CUBIC function can update ca->cnt at most once per jiffy.
+ * On all cwnd reduction events, ca->epoch_start is set to 0,
+ * which will force a recalculation of ca->cnt.
+ */
+ if (ca->epoch_start && tcp_jiffies32 == ca->last_time)
+ goto tcp_friendliness;
+
+ ca->last_cwnd = cwnd;
+ ca->last_time = tcp_jiffies32;
+
+ if (ca->epoch_start == 0) {
+ ca->epoch_start = tcp_jiffies32; /* record beginning */
+ ca->ack_cnt = acked; /* start counting */
+ ca->tcp_cwnd = cwnd; /* syn with cubic */
+
+ if (ca->last_max_cwnd <= cwnd) {
+ ca->bic_K = 0;
+ ca->bic_origin_point = cwnd;
+ } else {
+ /* Compute new K based on
+ * (wmax-cwnd) * (srtt>>3 / HZ) / c * 2^(3*bictcp_HZ)
+ */
+ ca->bic_K = cubic_root(cube_factor
+ * (ca->last_max_cwnd - cwnd));
+ ca->bic_origin_point = ca->last_max_cwnd;
+ }
+ }
+
+ /* cubic function - calc*/
+ /* calculate c * time^3 / rtt,
+ * while considering overflow in calculation of time^3
+ * (so time^3 is done by using 64 bit)
+ * and without the support of division of 64bit numbers
+ * (so all divisions are done by using 32 bit)
+ * also NOTE the unit of those veriables
+ * time = (t - K) / 2^bictcp_HZ
+ * c = bic_scale >> 10
+ * rtt = (srtt >> 3) / HZ
+ * !!! The following code does not have overflow problems,
+ * if the cwnd < 1 million packets !!!
+ */
+
+ t = (__s32)(tcp_jiffies32 - ca->epoch_start) * USEC_PER_JIFFY;
+ t += ca->delay_min;
+ /* change the unit from usec to bictcp_HZ */
+ t <<= BICTCP_HZ;
+ t /= USEC_PER_SEC;
+
+ if (t < ca->bic_K) /* t - K */
+ offs = ca->bic_K - t;
+ else
+ offs = t - ca->bic_K;
+
+ /* c/rtt * (t-K)^3 */
+ delta = (cube_rtt_scale * offs * offs * offs) >> (10+3*BICTCP_HZ);
+ if (t < ca->bic_K) /* below origin*/
+ bic_target = ca->bic_origin_point - delta;
+ else /* above origin*/
+ bic_target = ca->bic_origin_point + delta;
+
+ /* cubic function - calc bictcp_cnt*/
+ if (bic_target > cwnd) {
+ ca->cnt = cwnd / (bic_target - cwnd);
+ } else {
+ ca->cnt = 100 * cwnd; /* very small increment*/
+ }
+
+ /*
+ * The initial growth of cubic function may be too conservative
+ * when the available bandwidth is still unknown.
+ */
+ if (ca->last_max_cwnd == 0 && ca->cnt > 20)
+ ca->cnt = 20; /* increase cwnd 5% per RTT */
+
+tcp_friendliness:
+ /* TCP Friendly */
+ if (tcp_friendliness) {
+ __u32 scale = beta_scale;
+ __u32 n;
+
+ /* update tcp cwnd */
+ delta = (cwnd * scale) >> 3;
+ if (ca->ack_cnt > delta && delta) {
+ n = ca->ack_cnt / delta;
+ ca->ack_cnt -= n * delta;
+ ca->tcp_cwnd += n;
+ }
+
+ if (ca->tcp_cwnd > cwnd) { /* if bic is slower than tcp */
+ delta = ca->tcp_cwnd - cwnd;
+ max_cnt = cwnd / delta;
+ if (ca->cnt > max_cnt)
+ ca->cnt = max_cnt;
+ }
+ }
+
+ /* The maximum rate of cwnd increase CUBIC allows is 1 packet per
+ * 2 packets ACKed, meaning cwnd grows at 1.5x per RTT.
+ */
+ ca->cnt = max(ca->cnt, 2U);
+}
+
+/* Or simply use the BPF_STRUCT_OPS to avoid the SEC boiler plate. */
+void BPF_STRUCT_OPS(bictcp_cong_avoid, struct sock *sk, __u32 ack, __u32 acked)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct bictcp *ca = inet_csk_ca(sk);
+
+ if (!tcp_is_cwnd_limited(sk))
+ return;
+
+ if (tcp_in_slow_start(tp)) {
+ if (hystart && after(ack, ca->end_seq))
+ bictcp_hystart_reset(sk);
+ acked = tcp_slow_start(tp, acked);
+ if (!acked)
+ return;
+ }
+ bictcp_update(ca, tp->snd_cwnd, acked);
+ tcp_cong_avoid_ai(tp, ca->cnt, acked);
+}
+
+__u32 BPF_STRUCT_OPS(bictcp_recalc_ssthresh, struct sock *sk)
+{
+ const struct tcp_sock *tp = tcp_sk(sk);
+ struct bictcp *ca = inet_csk_ca(sk);
+
+ ca->epoch_start = 0; /* end of epoch */
+
+ /* Wmax and fast convergence */
+ if (tp->snd_cwnd < ca->last_max_cwnd && fast_convergence)
+ ca->last_max_cwnd = (tp->snd_cwnd * (BICTCP_BETA_SCALE + beta))
+ / (2 * BICTCP_BETA_SCALE);
+ else
+ ca->last_max_cwnd = tp->snd_cwnd;
+
+ return max((tp->snd_cwnd * beta) / BICTCP_BETA_SCALE, 2U);
+}
+
+void BPF_STRUCT_OPS(bictcp_state, struct sock *sk, __u8 new_state)
+{
+ if (new_state == TCP_CA_Loss) {
+ bictcp_reset(inet_csk_ca(sk));
+ bictcp_hystart_reset(sk);
+ }
+}
+
+#define GSO_MAX_SIZE 65536
+
+/* Account for TSO/GRO delays.
+ * Otherwise short RTT flows could get too small ssthresh, since during
+ * slow start we begin with small TSO packets and ca->delay_min would
+ * not account for long aggregation delay when TSO packets get bigger.
+ * Ideally even with a very small RTT we would like to have at least one
+ * TSO packet being sent and received by GRO, and another one in qdisc layer.
+ * We apply another 100% factor because @rate is doubled at this point.
+ * We cap the cushion to 1ms.
+ */
+static __always_inline __u32 hystart_ack_delay(struct sock *sk)
+{
+ unsigned long rate;
+
+ rate = sk->sk_pacing_rate;
+ if (!rate)
+ return 0;
+ return min((__u64)USEC_PER_MSEC,
+ div64_ul((__u64)GSO_MAX_SIZE * 4 * USEC_PER_SEC, rate));
+}
+
+static __always_inline void hystart_update(struct sock *sk, __u32 delay)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct bictcp *ca = inet_csk_ca(sk);
+ __u32 threshold;
+
+ if (hystart_detect & HYSTART_ACK_TRAIN) {
+ __u32 now = bictcp_clock_us(sk);
+
+ /* first detection parameter - ack-train detection */
+ if ((__s32)(now - ca->last_ack) <= hystart_ack_delta_us) {
+ ca->last_ack = now;
+
+ threshold = ca->delay_min + hystart_ack_delay(sk);
+
+ /* Hystart ack train triggers if we get ack past
+ * ca->delay_min/2.
+ * Pacing might have delayed packets up to RTT/2
+ * during slow start.
+ */
+ if (sk->sk_pacing_status == SK_PACING_NONE)
+ threshold >>= 1;
+
+ if ((__s32)(now - ca->round_start) > threshold) {
+ ca->found = 1;
+ tp->snd_ssthresh = tp->snd_cwnd;
+ }
+ }
+ }
+
+ if (hystart_detect & HYSTART_DELAY) {
+ /* obtain the minimum delay of more than sampling packets */
+ if (ca->sample_cnt < HYSTART_MIN_SAMPLES) {
+ if (ca->curr_rtt > delay)
+ ca->curr_rtt = delay;
+
+ ca->sample_cnt++;
+ } else {
+ if (ca->curr_rtt > ca->delay_min +
+ HYSTART_DELAY_THRESH(ca->delay_min >> 3)) {
+ ca->found = 1;
+ tp->snd_ssthresh = tp->snd_cwnd;
+ }
+ }
+ }
+}
+
+void BPF_STRUCT_OPS(bictcp_acked, struct sock *sk,
+ const struct ack_sample *sample)
+{
+ const struct tcp_sock *tp = tcp_sk(sk);
+ struct bictcp *ca = inet_csk_ca(sk);
+ __u32 delay;
+
+ /* Some calls are for duplicates without timetamps */
+ if (sample->rtt_us < 0)
+ return;
+
+ /* Discard delay samples right after fast recovery */
+ if (ca->epoch_start && (__s32)(tcp_jiffies32 - ca->epoch_start) < HZ)
+ return;
+
+ delay = sample->rtt_us;
+ if (delay == 0)
+ delay = 1;
+
+ /* first time call or link delay decreases */
+ if (ca->delay_min == 0 || ca->delay_min > delay)
+ ca->delay_min = delay;
+
+ /* hystart triggers when cwnd is larger than some threshold */
+ if (!ca->found && tcp_in_slow_start(tp) && hystart &&
+ tp->snd_cwnd >= hystart_low_window)
+ hystart_update(sk, delay);
+}
+
+__u32 BPF_STRUCT_OPS(tcp_reno_undo_cwnd, struct sock *sk)
+{
+ const struct tcp_sock *tp = tcp_sk(sk);
+
+ return max(tp->snd_cwnd, tp->prior_cwnd);
+}
+
+SEC(".struct_ops")
+struct tcp_congestion_ops cubic = {
+ .init = (void *)bictcp_init,
+ .ssthresh = (void *)bictcp_recalc_ssthresh,
+ .cong_avoid = (void *)bictcp_cong_avoid,
+ .set_state = (void *)bictcp_state,
+ .undo_cwnd = (void *)tcp_reno_undo_cwnd,
+ .cwnd_event = (void *)bictcp_cwnd_event,
+ .pkts_acked = (void *)bictcp_acked,
+ .name = "bpf_cubic",
+};