From patchwork Tue Feb 21 12:18:39 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "D. Wythe" X-Patchwork-Id: 13147838 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 28CE6C6FA99 for ; Tue, 21 Feb 2023 12:19:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234609AbjBUMTr (ORCPT ); Tue, 21 Feb 2023 07:19:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233557AbjBUMTo (ORCPT ); Tue, 21 Feb 2023 07:19:44 -0500 Received: from out30-99.freemail.mail.aliyun.com (out30-99.freemail.mail.aliyun.com [115.124.30.99]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D7042916E; Tue, 21 Feb 2023 04:19:15 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R211e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046059;MF=alibuda@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0VcCKDVE_1676981927; Received: from j66a10360.sqa.eu95.tbsite.net(mailfrom:alibuda@linux.alibaba.com fp:SMTPD_---0VcCKDVE_1676981927) by smtp.aliyun-inc.com; Tue, 21 Feb 2023 20:18:48 +0800 From: "D. Wythe" To: kgraul@linux.ibm.com, wenjia@linux.ibm.com, jaka@linux.ibm.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org Cc: kuba@kernel.org, davem@davemloft.net, netdev@vger.kernel.org, linux-s390@vger.kernel.org, linux-rdma@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH bpf-next v2 2/2] bpf/selftests: add selftest for SMC bpf capability Date: Tue, 21 Feb 2023 20:18:39 +0800 Message-Id: <1676981919-64884-3-git-send-email-alibuda@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1676981919-64884-1-git-send-email-alibuda@linux.alibaba.com> References: <1676981919-64884-1-git-send-email-alibuda@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org From: "D. Wythe" This PATCH adds a tiny selftest for SMC bpf capability, making decisions on whether to use SMC by collecting certain information from kernel smc sock. Follow the steps below to run this test. make -C tools/testing/selftests/bpf cd tools/testing/selftests/bpf sudo ./test_progs -t bpf_smc Results shows: 18 bpf_smc:OK Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: D. Wythe --- tools/testing/selftests/bpf/prog_tests/bpf_smc.c | 39 +++ tools/testing/selftests/bpf/progs/bpf_smc.c | 315 +++++++++++++++++++++++ 2 files changed, 354 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_smc.c create mode 100644 tools/testing/selftests/bpf/progs/bpf_smc.c diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_smc.c b/tools/testing/selftests/bpf/prog_tests/bpf_smc.c new file mode 100644 index 0000000..b143932 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/bpf_smc.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2019 Facebook */ + +#include +#include +#include +#include "bpf_smc.skel.h" + +void test_bpf_smc(void) +{ + struct bpf_smc *smc_skel; + struct bpf_link *link; + int err; + + smc_skel = bpf_smc__open(); + if (!ASSERT_OK_PTR(smc_skel, "skel_open")) + return; + + err = bpf_map__set_type(smc_skel->maps.negotiator_map, BPF_MAP_TYPE_HASH); + if (!ASSERT_OK(err, "bpf_map__set_type")) + goto error; + + err = bpf_map__set_max_entries(smc_skel->maps.negotiator_map, 1); + if (!ASSERT_OK(err, "bpf_map__set_type")) + goto error; + + err = bpf_smc__load(smc_skel); + if (!ASSERT_OK(err, "skel_load")) + goto error; + + link = bpf_map__attach_struct_ops(smc_skel->maps.ops); + if (!ASSERT_OK_PTR(link, "bpf_map__attach_struct_ops")) + goto error; + + bpf_link__destroy(link); +error: + bpf_smc__destroy(smc_skel); +} + diff --git a/tools/testing/selftests/bpf/progs/bpf_smc.c b/tools/testing/selftests/bpf/progs/bpf_smc.c new file mode 100644 index 0000000..78c7976 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/bpf_smc.c @@ -0,0 +1,315 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include +#include +#include +#include +#include +#include +#include +#include + +#define BPF_STRUCT_OPS(name, args...) \ + SEC("struct_ops/"#name) \ + BPF_PROG(name, args) + +#define SMC_LISTEN (10) +#define SMC_SOCK_CLOSED_TIMING (0) +extern unsigned long CONFIG_HZ __kconfig; +#define HZ CONFIG_HZ + +char _license[] SEC("license") = "GPL"; +#define max(a, b) ((a) > (b) ? (a) : (b)) + +struct sock_common { + unsigned char skc_state; + __u16 skc_num; +} __attribute__((preserve_access_index)); + +struct sock { + struct sock_common __sk_common; + int sk_sndbuf; +} __attribute__((preserve_access_index)); + +struct inet_sock { + struct sock sk; +} __attribute__((preserve_access_index)); + +struct inet_connection_sock { + struct inet_sock icsk_inet; +} __attribute__((preserve_access_index)); + +struct tcp_sock { + struct inet_connection_sock inet_conn; + __u32 rcv_nxt; + __u32 snd_nxt; + __u32 snd_una; + __u32 delivered; + __u8 syn_data:1, /* SYN includes data */ + syn_fastopen:1, /* SYN includes Fast Open option */ + syn_fastopen_exp:1,/* SYN includes Fast Open exp. option */ + syn_fastopen_ch:1, /* Active TFO re-enabling probe */ + syn_data_acked:1,/* data in SYN is acked by SYN-ACK */ + save_syn:1, /* Save headers of SYN packet */ + is_cwnd_limited:1,/* forward progress limited by snd_cwnd? */ + syn_smc:1; /* SYN includes SMC */ +} __attribute__((preserve_access_index)); + +struct socket { + struct sock *sk; +} __attribute__((preserve_access_index)); + +union smc_host_cursor { + struct { + __u16 reserved; + __u16 wrap; + __u32 count; + }; +} __attribute__((preserve_access_index)); + +struct smc_connection { + union smc_host_cursor tx_curs_sent; + union smc_host_cursor rx_curs_confirmed; +} __attribute__((preserve_access_index)); + +struct smc_sock { + struct sock sk; + struct socket *clcsock; /* internal tcp socket */ + struct smc_connection conn; + int use_fallback; +} __attribute__((preserve_access_index)); + +static __always_inline struct tcp_sock *tcp_sk(const struct sock *sk) +{ + return (struct tcp_sock *)sk; +} + +static __always_inline struct smc_sock *smc_sk(struct sock *sk) +{ + return (struct smc_sock *)sk; +} + +struct smc_prediction { + /* protection for smc_prediction */ + struct bpf_spin_lock lock; + /* start of time slice */ + __u64 start_tstamp; + /* delta of pacing */ + __u64 pacing_delta; + /* N of closed connections determined as long connections + * in current time slice + */ + __u32 closed_long_cc; + /* N of closed connections in this time slice */ + __u32 closed_total_cc; + /* N of incoming connections determined as long connections + * in current time slice + */ + __u32 incoming_long_cc; + /* last splice rate of long cc */ + __u32 last_rate_of_lcc; +}; + +#define SMC_PREDICTION_MIN_PACING_DELTA (1llu) +#define SMC_PREDICTION_MAX_PACING_DELTA (HZ << 3) +#define SMC_PREDICTION_MAX_LONGCC_PER_SPLICE (8) +#define SMC_PREDICTION_MAX_PORT (64) +#define SMC_PREDICTION_MAX_SPLICE_GAP (1) +#define SMC_PREDICTION_LONGCC_RATE_THRESHOLD (13189) +#define SMC_PREDICTION_LONGCC_PACKETS_THRESHOLD (100) +#define SMC_PREDICTION_LONGCC_BYTES_THRESHOLD \ + (SMC_PREDICTION_LONGCC_PACKETS_THRESHOLD * 1024) + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(max_entries, SMC_PREDICTION_MAX_PORT); + __type(key, __u16); + __type(value, struct smc_prediction); +} negotiator_map SEC(".maps"); + + +static inline __u32 smc_prediction_calt_rate(struct smc_prediction *smc_predictor) +{ + if (!smc_predictor->closed_total_cc) + return smc_predictor->last_rate_of_lcc; + + return (smc_predictor->closed_long_cc << 14) / smc_predictor->closed_total_cc; +} + +static inline struct smc_prediction *smc_prediction_get(const struct smc_sock *smc, + const struct tcp_sock *tp, __u64 tstamp) +{ + struct smc_prediction zero = {}, *smc_predictor; + __u16 key; + __u32 gap; + int err; + + err = bpf_core_read(&key, sizeof(__u16), &tp->inet_conn.icsk_inet.sk.__sk_common.skc_num); + if (err) + return NULL; + + /* BAD key */ + if (key == 0) + return NULL; + + smc_predictor = bpf_map_lookup_elem(&negotiator_map, &key); + if (!smc_predictor) { + zero.start_tstamp = bpf_jiffies64(); + zero.pacing_delta = SMC_PREDICTION_MIN_PACING_DELTA; + bpf_map_update_elem(&negotiator_map, &key, &zero, 0); + smc_predictor = bpf_map_lookup_elem(&negotiator_map, &key); + if (!smc_predictor) + return NULL; + } + + if (tstamp) { + bpf_spin_lock(&smc_predictor->lock); + gap = (tstamp - smc_predictor->start_tstamp) / smc_predictor->pacing_delta; + /* new splice */ + if (gap > 0) { + smc_predictor->start_tstamp = tstamp; + smc_predictor->last_rate_of_lcc = + (smc_prediction_calt_rate(smc_predictor) * 7) >> (2 + gap); + smc_predictor->closed_long_cc = 0; + smc_predictor->closed_total_cc = 0; + smc_predictor->incoming_long_cc = 0; + } + bpf_spin_unlock(&smc_predictor->lock); + } + return smc_predictor; +} + +/* BPF struct ops for smc protocol negotiator */ +struct smc_sock_negotiator_ops { + /* ret for negotiate */ + int (*negotiate)(struct smc_sock *smc); + + /* info gathering timing */ + void (*collect_info)(struct smc_sock *smc, int timing); +}; + +int BPF_STRUCT_OPS(bpf_smc_negotiate, struct smc_sock *smc) +{ + struct smc_prediction *smc_predictor; + struct tcp_sock *tp; + struct sock *clcsk; + int ret = SK_DROP; + __u32 rate = 0; + + /* Only make decison during listen */ + if (smc->sk.__sk_common.skc_state != SMC_LISTEN) + return SK_PASS; + + clcsk = BPF_CORE_READ(smc, clcsock, sk); + if (!clcsk) + goto error; + + tp = tcp_sk(clcsk); + if (!tp) + goto error; + + smc_predictor = smc_prediction_get(smc, tp, bpf_jiffies64()); + if (!smc_predictor) + return SK_PASS; + + bpf_spin_lock(&smc_predictor->lock); + + if (smc_predictor->incoming_long_cc == 0) + goto out_locked_pass; + + if (smc_predictor->incoming_long_cc > SMC_PREDICTION_MAX_LONGCC_PER_SPLICE) { + ret = 100; + goto out_locked_drop; + } + + rate = smc_prediction_calt_rate(smc_predictor); + if (rate < SMC_PREDICTION_LONGCC_RATE_THRESHOLD) { + ret = 200; + goto out_locked_drop; + } +out_locked_pass: + smc_predictor->incoming_long_cc++; + bpf_spin_unlock(&smc_predictor->lock); + return SK_PASS; +out_locked_drop: + bpf_spin_unlock(&smc_predictor->lock); +error: + return SK_DROP; +} + +void BPF_STRUCT_OPS(bpf_smc_collect_info, struct smc_sock *smc, int timing) +{ + struct smc_prediction *smc_predictor; + int use_fallback, sndbuf, err; + struct tcp_sock *tp; + struct sock *clcsk; + __u16 wrap, count; + __u32 delivered; + bool match = false; + + /* only fouces on closed */ + if (timing != SMC_SOCK_CLOSED_TIMING) + return; + + clcsk = BPF_CORE_READ(smc, clcsock, sk); + if (!clcsk) + goto error; + + tp = tcp_sk(clcsk); + if (!tp) + goto error; + + smc_predictor = smc_prediction_get(smc, tp, 0); + if (!smc_predictor) + goto error; + + err = bpf_core_read(&use_fallback, sizeof(use_fallback), &smc->use_fallback); + if (err) + goto error; + + if (use_fallback) { + err = bpf_core_read(&delivered, sizeof(delivered), &tp->delivered); + if (err) + goto error; + + match = (delivered > SMC_PREDICTION_LONGCC_PACKETS_THRESHOLD); + + } else { + delivered = 0; /* tcp delivered */ + err = bpf_core_read(&wrap, sizeof(__u16), &smc->conn.tx_curs_sent.wrap); + if (err) + goto error; + err = bpf_core_read(&count, sizeof(__u16), &smc->conn.tx_curs_sent.count); + if (err) + goto error; + err = bpf_core_read(&sndbuf, sizeof(int), &clcsk->sk_sndbuf); + if (err) + goto error; + + match = (count + wrap * sndbuf) > SMC_PREDICTION_LONGCC_BYTES_THRESHOLD; + } + bpf_spin_lock(&smc_predictor->lock); + smc_predictor->closed_total_cc++; + if (match) { + /* increase stats */ + smc_predictor->closed_long_cc++; + /* try more aggressive */ + if (smc_predictor->pacing_delta > SMC_PREDICTION_MIN_PACING_DELTA) { + if (use_fallback) { + smc_predictor->pacing_delta = max(SMC_PREDICTION_MIN_PACING_DELTA, + (smc_predictor->pacing_delta * 3) >> 2); + } + } + } else if (!use_fallback) { + smc_predictor->pacing_delta <<= 1; + } + bpf_spin_unlock(&smc_predictor->lock); +error: + return; +} + +SEC(".struct_ops") +struct smc_sock_negotiator_ops ops = { + .negotiate = (void *)bpf_smc_negotiate, + .collect_info = (void *)bpf_smc_collect_info, +};