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#!/usr/bin/python3
from bcc import BPF
source = r"""
BPF_TASK_STORAGE(task_storage_map, __u64);
KFUNC_PROBE(inet_listen)
{
__u64 ts = bpf_ktime_get_ns();
/* save timestamp to local storage on function entry */
task_storage_map.task_storage_get(bpf_get_current_task_btf(), &ts, BPF_LOCAL_STORAGE_GET_F_CREATE);
bpf_trace_printk("inet_listen entry: store timestamp %lld", ts);
return 0;
}
KRETFUNC_PROBE(inet_listen)
{
__u64 *ts;
/* retrieve timestamp stored at local storage on function exit */
ts = task_storage_map.task_storage_get(bpf_get_current_task_btf(), 0, 0);
if (!ts)
return 0;
/* delete timestamp from local storage */
task_storage_map.task_storage_delete(bpf_get_current_task_btf());
/* calculate latency */
bpf_trace_printk("inet_listen exit: cost %lldus", (bpf_ktime_get_ns() - *ts) / 1000);
return 0;
}
"""
b = BPF(text=source)
try:
b.trace_print()
except KeyboardInterrupt:
pass
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