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62 lines
1.4 KiB
62 lines
1.4 KiB
7 months ago
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#!/usr/bin/env python
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#
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# This is a Hello World example that uses BPF_PERF_OUTPUT.
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from bcc import BPF
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import ctypes as ct
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# define BPF program
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prog = """
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#include <linux/sched.h>
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// define output data structure in C
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struct data_t {
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u32 pid;
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u64 ts;
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char comm[TASK_COMM_LEN];
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};
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BPF_PERF_OUTPUT(events);
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int hello(struct pt_regs *ctx) {
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struct data_t data = {};
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data.pid = bpf_get_current_pid_tgid();
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data.ts = bpf_ktime_get_ns();
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bpf_get_current_comm(&data.comm, sizeof(data.comm));
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events.perf_submit(ctx, &data, sizeof(data));
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return 0;
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}
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"""
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# load BPF program
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b = BPF(text=prog)
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b.attach_kprobe(event=b.get_syscall_fnname("clone"), fn_name="hello")
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# define output data structure in Python
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TASK_COMM_LEN = 16 # linux/sched.h
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class Data(ct.Structure):
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_fields_ = [("pid", ct.c_uint),
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("ts", ct.c_ulonglong),
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("comm", ct.c_char * TASK_COMM_LEN)]
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# header
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print("%-18s %-16s %-6s %s" % ("TIME(s)", "COMM", "PID", "MESSAGE"))
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# process event
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start = 0
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def print_event(cpu, data, size):
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global start
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event = ct.cast(data, ct.POINTER(Data)).contents
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if start == 0:
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start = event.ts
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time_s = (float(event.ts - start)) / 1000000000
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print("%-18.9f %-16s %-6d %s" % (time_s, event.comm, event.pid,
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"Hello, perf_output!"))
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# loop with callback to print_event
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b["events"].open_perf_buffer(print_event)
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while 1:
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b.perf_buffer_poll()
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