1#!/usr/bin/env python
2# @lint-avoid-python-3-compatibility-imports
3#
4# syncsnoop Trace sync() syscall.
5#           For Linux, uses BCC, eBPF. Embedded C.
6#
7# Written as a basic example of BCC trace & reformat. See
8# examples/hello_world.py for a BCC trace with default output example.
9#
10# Copyright (c) 2015 Brendan Gregg.
11# Licensed under the Apache License, Version 2.0 (the "License")
12#
13# 13-Aug-2015   Brendan Gregg   Created this.
14# 19-Feb-2016   Allan McAleavy migrated to BPF_PERF_OUTPUT
15
16from __future__ import print_function
17from bcc import BPF
18import ctypes as ct
19
20# load BPF program
21b = BPF(text="""
22struct data_t {
23    u64 ts;
24};
25
26BPF_PERF_OUTPUT(events);
27
28void syscall__sync(void *ctx) {
29    struct data_t data = {};
30    data.ts = bpf_ktime_get_ns() / 1000;
31    events.perf_submit(ctx, &data, sizeof(data));
32};
33""")
34b.attach_kprobe(event=b.get_syscall_fnname("sync"),
35                fn_name="syscall__sync")
36
37class Data(ct.Structure):
38    _fields_ = [
39        ("ts", ct.c_ulonglong)
40    ]
41
42# header
43print("%-18s %s" % ("TIME(s)", "CALL"))
44
45# process event
46def print_event(cpu, data, size):
47    event = ct.cast(data, ct.POINTER(Data)).contents
48    print("%-18.9f sync()" % (float(event.ts) / 1000000))
49
50# loop with callback to print_event
51b["events"].open_perf_buffer(print_event)
52while 1:
53    try:
54        b.perf_buffer_poll()
55    except KeyboardInterrupt:
56        exit()
57