| #!/usr/bin/python |
| # @lint-avoid-python-3-compatibility-imports |
| # |
| # tcpconnlat Trace TCP active connection latency (connect). |
| # For Linux, uses BCC, eBPF. Embedded C. |
| # |
| # USAGE: tcpconnlat [-h] [-t] [-p PID] |
| # |
| # This uses dynamic tracing of kernel functions, and will need to be updated |
| # to match kernel changes. |
| # |
| # Copyright 2016 Netflix, Inc. |
| # Licensed under the Apache License, Version 2.0 (the "License") |
| # |
| # 19-Feb-2016 Brendan Gregg Created this. |
| |
| from __future__ import print_function |
| from bcc import BPF |
| from socket import inet_ntop, AF_INET, AF_INET6 |
| from struct import pack |
| import argparse |
| import ctypes as ct |
| |
| # arg validation |
| def positive_float(val): |
| try: |
| ival = float(val) |
| except ValueError: |
| raise argparse.ArgumentTypeError("must be a float") |
| |
| if ival < 0: |
| raise argparse.ArgumentTypeError("must be positive") |
| return ival |
| |
| # arguments |
| examples = """examples: |
| ./tcpconnlat # trace all TCP connect()s |
| ./tcpconnlat 1 # trace connection latency slower than 1 ms |
| ./tcpconnlat 0.1 # trace connection latency slower than 100 us |
| ./tcpconnlat -t # include timestamps |
| ./tcpconnlat -p 181 # only trace PID 181 |
| """ |
| parser = argparse.ArgumentParser( |
| description="Trace TCP connects and show connection latency", |
| formatter_class=argparse.RawDescriptionHelpFormatter, |
| epilog=examples) |
| parser.add_argument("-t", "--timestamp", action="store_true", |
| help="include timestamp on output") |
| parser.add_argument("-p", "--pid", |
| help="trace this PID only") |
| parser.add_argument("duration_ms", nargs="?", default=0, |
| type=positive_float, |
| help="minimum duration to trace (ms)") |
| parser.add_argument("-v", "--verbose", action="store_true", |
| help="print the BPF program for debugging purposes") |
| parser.add_argument("--ebpf", action="store_true", |
| help=argparse.SUPPRESS) |
| args = parser.parse_args() |
| |
| if args.duration_ms: |
| # support fractions but round to nearest microsecond |
| duration_us = int(args.duration_ms * 1000) |
| else: |
| duration_us = 0 # default is show all |
| |
| debug = 0 |
| |
| # define BPF program |
| bpf_text = """ |
| #include <uapi/linux/ptrace.h> |
| #include <net/sock.h> |
| #include <net/tcp_states.h> |
| #include <bcc/proto.h> |
| |
| struct info_t { |
| u64 ts; |
| u64 pid; |
| char task[TASK_COMM_LEN]; |
| }; |
| BPF_HASH(start, struct sock *, struct info_t); |
| |
| // separate data structs for ipv4 and ipv6 |
| struct ipv4_data_t { |
| // XXX: switch some to u32's when supported |
| u64 ts_us; |
| u64 pid; |
| u64 saddr; |
| u64 daddr; |
| u64 ip; |
| u64 dport; |
| u64 delta_us; |
| char task[TASK_COMM_LEN]; |
| }; |
| BPF_PERF_OUTPUT(ipv4_events); |
| |
| struct ipv6_data_t { |
| u64 ts_us; |
| u64 pid; |
| unsigned __int128 saddr; |
| unsigned __int128 daddr; |
| u64 ip; |
| u64 dport; |
| u64 delta_us; |
| char task[TASK_COMM_LEN]; |
| }; |
| BPF_PERF_OUTPUT(ipv6_events); |
| |
| int trace_connect(struct pt_regs *ctx, struct sock *sk) |
| { |
| u32 pid = bpf_get_current_pid_tgid(); |
| FILTER |
| struct info_t info = {.pid = pid}; |
| info.ts = bpf_ktime_get_ns(); |
| bpf_get_current_comm(&info.task, sizeof(info.task)); |
| start.update(&sk, &info); |
| return 0; |
| }; |
| |
| // See tcp_v4_do_rcv() and tcp_v6_do_rcv(). So TCP_ESTBALISHED and TCP_LISTEN |
| // are fast path and processed elsewhere, and leftovers are processed by |
| // tcp_rcv_state_process(). We can trace this for handshake completion. |
| // This should all be switched to static tracepoints when available. |
| int trace_tcp_rcv_state_process(struct pt_regs *ctx, struct sock *skp) |
| { |
| // will be in TCP_SYN_SENT for handshake |
| if (skp->__sk_common.skc_state != TCP_SYN_SENT) |
| return 0; |
| |
| // check start and calculate delta |
| struct info_t *infop = start.lookup(&skp); |
| if (infop == 0) { |
| return 0; // missed entry or filtered |
| } |
| |
| u64 ts = infop->ts; |
| u64 now = bpf_ktime_get_ns(); |
| |
| u64 delta_us = (now - ts) / 1000ul; |
| |
| #ifdef MIN_LATENCY |
| if ( delta_us < DURATION_US ) { |
| return 0; // connect latency is below latency filter minimum |
| } |
| #endif |
| |
| // pull in details |
| u16 family = 0, dport = 0; |
| family = skp->__sk_common.skc_family; |
| dport = skp->__sk_common.skc_dport; |
| |
| // emit to appropriate data path |
| if (family == AF_INET) { |
| struct ipv4_data_t data4 = {.pid = infop->pid, .ip = 4}; |
| data4.ts_us = now / 1000; |
| data4.saddr = skp->__sk_common.skc_rcv_saddr; |
| data4.daddr = skp->__sk_common.skc_daddr; |
| data4.dport = ntohs(dport); |
| data4.delta_us = delta_us; |
| __builtin_memcpy(&data4.task, infop->task, sizeof(data4.task)); |
| ipv4_events.perf_submit(ctx, &data4, sizeof(data4)); |
| |
| } else /* AF_INET6 */ { |
| struct ipv6_data_t data6 = {.pid = infop->pid, .ip = 6}; |
| data6.ts_us = now / 1000; |
| bpf_probe_read(&data6.saddr, sizeof(data6.saddr), |
| skp->__sk_common.skc_v6_rcv_saddr.in6_u.u6_addr32); |
| bpf_probe_read(&data6.daddr, sizeof(data6.daddr), |
| skp->__sk_common.skc_v6_daddr.in6_u.u6_addr32); |
| data6.dport = ntohs(dport); |
| data6.delta_us = delta_us; |
| __builtin_memcpy(&data6.task, infop->task, sizeof(data6.task)); |
| ipv6_events.perf_submit(ctx, &data6, sizeof(data6)); |
| } |
| |
| start.delete(&skp); |
| |
| return 0; |
| } |
| """ |
| |
| if duration_us > 0: |
| bpf_text = "#define MIN_LATENCY\n" + bpf_text |
| bpf_text = bpf_text.replace('DURATION_US', str(duration_us)) |
| |
| # code substitutions |
| if args.pid: |
| bpf_text = bpf_text.replace('FILTER', |
| 'if (pid != %s) { return 0; }' % args.pid) |
| else: |
| bpf_text = bpf_text.replace('FILTER', '') |
| if debug or args.verbose or args.ebpf: |
| print(bpf_text) |
| if args.ebpf: |
| exit() |
| |
| # initialize BPF |
| b = BPF(text=bpf_text) |
| b.attach_kprobe(event="tcp_v4_connect", fn_name="trace_connect") |
| b.attach_kprobe(event="tcp_v6_connect", fn_name="trace_connect") |
| b.attach_kprobe(event="tcp_rcv_state_process", |
| fn_name="trace_tcp_rcv_state_process") |
| |
| # event data |
| TASK_COMM_LEN = 16 # linux/sched.h |
| |
| class Data_ipv4(ct.Structure): |
| _fields_ = [ |
| ("ts_us", ct.c_ulonglong), |
| ("pid", ct.c_ulonglong), |
| ("saddr", ct.c_ulonglong), |
| ("daddr", ct.c_ulonglong), |
| ("ip", ct.c_ulonglong), |
| ("dport", ct.c_ulonglong), |
| ("delta_us", ct.c_ulonglong), |
| ("task", ct.c_char * TASK_COMM_LEN) |
| ] |
| |
| class Data_ipv6(ct.Structure): |
| _fields_ = [ |
| ("ts_us", ct.c_ulonglong), |
| ("pid", ct.c_ulonglong), |
| ("saddr", (ct.c_ulonglong * 2)), |
| ("daddr", (ct.c_ulonglong * 2)), |
| ("ip", ct.c_ulonglong), |
| ("dport", ct.c_ulonglong), |
| ("delta_us", ct.c_ulonglong), |
| ("task", ct.c_char * TASK_COMM_LEN) |
| ] |
| |
| # process event |
| start_ts = 0 |
| |
| def print_ipv4_event(cpu, data, size): |
| event = ct.cast(data, ct.POINTER(Data_ipv4)).contents |
| global start_ts |
| if args.timestamp: |
| if start_ts == 0: |
| start_ts = event.ts_us |
| print("%-9.3f" % ((float(event.ts_us) - start_ts) / 1000000), end="") |
| print("%-6d %-12.12s %-2d %-16s %-16s %-5d %.2f" % (event.pid, |
| event.task.decode(), event.ip, |
| inet_ntop(AF_INET, pack("I", event.saddr)), |
| inet_ntop(AF_INET, pack("I", event.daddr)), event.dport, |
| float(event.delta_us) / 1000)) |
| |
| def print_ipv6_event(cpu, data, size): |
| event = ct.cast(data, ct.POINTER(Data_ipv6)).contents |
| global start_ts |
| if args.timestamp: |
| if start_ts == 0: |
| start_ts = event.ts_us |
| print("%-9.3f" % ((float(event.ts_us) - start_ts) / 1000000), end="") |
| print("%-6d %-12.12s %-2d %-16s %-16s %-5d %.2f" % (event.pid, |
| event.task.decode(), event.ip, inet_ntop(AF_INET6, event.saddr), |
| inet_ntop(AF_INET6, event.daddr), event.dport, |
| float(event.delta_us) / 1000)) |
| |
| # header |
| if args.timestamp: |
| print("%-9s" % ("TIME(s)"), end="") |
| print("%-6s %-12s %-2s %-16s %-16s %-5s %s" % ("PID", "COMM", "IP", "SADDR", |
| "DADDR", "DPORT", "LAT(ms)")) |
| |
| # read events |
| b["ipv4_events"].open_perf_buffer(print_ipv4_event) |
| b["ipv6_events"].open_perf_buffer(print_ipv6_event) |
| while 1: |
| b.kprobe_poll() |