![Stanislav Fomichev](/assets/img/avatar_default.png)
Uses new RTT callback to dump stats every second. $ mkdir -p /tmp/cgroupv2 $ mount -t cgroup2 none /tmp/cgroupv2 $ mkdir -p /tmp/cgroupv2/foo $ echo $$ >> /tmp/cgroupv2/foo/cgroup.procs $ bpftool prog load ./tcp_dumpstats_kern.o /sys/fs/bpf/tcp_prog $ bpftool cgroup attach /tmp/cgroupv2/foo sock_ops pinned /sys/fs/bpf/tcp_prog $ bpftool prog tracelog $ # run neper/netperf/etc Used neper to compare performance with and without this program attached and didn't see any noticeable performance impact. Sample output: <idle>-0 [015] ..s. 2074.128800: 0: dsack_dups=0 delivered=242526 <idle>-0 [015] ..s. 2074.128808: 0: delivered_ce=0 icsk_retransmits=0 <idle>-0 [015] ..s. 2075.130133: 0: dsack_dups=0 delivered=323599 <idle>-0 [015] ..s. 2075.130138: 0: delivered_ce=0 icsk_retransmits=0 <idle>-0 [005] .Ns. 2076.131440: 0: dsack_dups=0 delivered=404648 <idle>-0 [005] .Ns. 2076.131447: 0: delivered_ce=0 icsk_retransmits=0 Cc: Eric Dumazet <edumazet@google.com> Cc: Priyaranjan Jha <priyarjha@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
69 lines
1.3 KiB
C
69 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Refer to samples/bpf/tcp_bpf.readme for the instructions on
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* how to run this sample program.
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*/
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#include <linux/bpf.h>
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#include "bpf_helpers.h"
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#include "bpf_endian.h"
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#define INTERVAL 1000000000ULL
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int _version SEC("version") = 1;
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char _license[] SEC("license") = "GPL";
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struct {
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__u32 type;
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__u32 map_flags;
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int *key;
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__u64 *value;
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} bpf_next_dump SEC(".maps") = {
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.type = BPF_MAP_TYPE_SK_STORAGE,
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.map_flags = BPF_F_NO_PREALLOC,
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};
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SEC("sockops")
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int _sockops(struct bpf_sock_ops *ctx)
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{
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struct bpf_tcp_sock *tcp_sk;
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struct bpf_sock *sk;
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__u64 *next_dump;
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__u64 now;
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switch (ctx->op) {
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case BPF_SOCK_OPS_TCP_CONNECT_CB:
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bpf_sock_ops_cb_flags_set(ctx, BPF_SOCK_OPS_RTT_CB_FLAG);
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return 1;
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case BPF_SOCK_OPS_RTT_CB:
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break;
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default:
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return 1;
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}
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sk = ctx->sk;
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if (!sk)
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return 1;
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next_dump = bpf_sk_storage_get(&bpf_next_dump, sk, 0,
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BPF_SK_STORAGE_GET_F_CREATE);
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if (!next_dump)
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return 1;
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now = bpf_ktime_get_ns();
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if (now < *next_dump)
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return 1;
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tcp_sk = bpf_tcp_sock(sk);
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if (!tcp_sk)
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return 1;
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*next_dump = now + INTERVAL;
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bpf_printk("dsack_dups=%u delivered=%u\n",
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tcp_sk->dsack_dups, tcp_sk->delivered);
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bpf_printk("delivered_ce=%u icsk_retransmits=%u\n",
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tcp_sk->delivered_ce, tcp_sk->icsk_retransmits);
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return 1;
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}
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