/
trace_perf_output.py
executable file
·54 lines (47 loc) · 1.38 KB
/
trace_perf_output.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
#!/usr/bin/env python
# Copyright (c) PLUMgrid, Inc.
# Licensed under the Apache License, Version 2.0 (the "License")
# This is an example of tracing an event and printing custom fields.
# run in project examples directory with:
# sudo ./trace_fields.py"
import atexit
from bcc import BPF
import ctypes as ct
class Data(ct.Structure):
_fields_ = [("ts", ct.c_ulonglong),
("magic", ct.c_ulonglong)]
counter = 0
def cb(cpu, data, size):
assert size >= ct.sizeof(Data)
event = ct.cast(data, ct.POINTER(Data)).contents
print("[%0d] %f: %x" % (cpu, float(event.ts) / 1000000, event.magic))
global counter
counter += 1
prog = """
BPF_PERF_OUTPUT(events);
BPF_ARRAY(counters, u64, 10);
int kprobe__sys_clone(void *ctx) {
struct {
u64 ts;
u64 magic;
} data = {bpf_ktime_get_ns(), 0x12345678};
int rc;
if ((rc = events.perf_submit(ctx, &data, sizeof(data))) < 0)
bpf_trace_printk("perf_output failed: %d\\n", rc);
int zero = 0;
u64 *val = counters.lookup(&zero);
if (val) lock_xadd(val, 1);
return 0;
}
"""
b = BPF(text=prog)
b["events"].open_perf_buffer(cb)
@atexit.register
def print_counter():
global counter
global b
print("counter = %d vs %d" % (counter, b["counters"][ct.c_int(0)].value))
print("Tracing sys_write, try `dd if=/dev/zero of=/dev/null`")
print("Tracing... Hit Ctrl-C to end.")
while 1:
b.perf_buffer_poll()