1*387f9dfdSAndroid Build Coastguard Worker#!/usr/bin/python 2*387f9dfdSAndroid Build Coastguard Worker# 3*387f9dfdSAndroid Build Coastguard Worker# gethostlatency Show latency for getaddrinfo/gethostbyname[2] calls. 4*387f9dfdSAndroid Build Coastguard Worker# For Linux, uses BCC, eBPF. Embedded C. 5*387f9dfdSAndroid Build Coastguard Worker# 6*387f9dfdSAndroid Build Coastguard Worker# This can be useful for identifying DNS latency, by identifying which 7*387f9dfdSAndroid Build Coastguard Worker# remote host name lookups were slow, and by how much. 8*387f9dfdSAndroid Build Coastguard Worker# 9*387f9dfdSAndroid Build Coastguard Worker# This uses dynamic tracing of user-level functions and registers, and may 10*387f9dfdSAndroid Build Coastguard Worker# need modifications to match your software and processor architecture. 11*387f9dfdSAndroid Build Coastguard Worker# 12*387f9dfdSAndroid Build Coastguard Worker# Copyright 2016 Netflix, Inc. 13*387f9dfdSAndroid Build Coastguard Worker# Licensed under the Apache License, Version 2.0 (the "License") 14*387f9dfdSAndroid Build Coastguard Worker# 15*387f9dfdSAndroid Build Coastguard Worker# 28-Jan-2016 Brendan Gregg Created this. 16*387f9dfdSAndroid Build Coastguard Worker 17*387f9dfdSAndroid Build Coastguard Workerfrom __future__ import print_function 18*387f9dfdSAndroid Build Coastguard Workerfrom bcc import BPF 19*387f9dfdSAndroid Build Coastguard Workerfrom time import strftime 20*387f9dfdSAndroid Build Coastguard Worker 21*387f9dfdSAndroid Build Coastguard Worker# load BPF program 22*387f9dfdSAndroid Build Coastguard Workerbpf_text = """ 23*387f9dfdSAndroid Build Coastguard Worker#include <uapi/linux/ptrace.h> 24*387f9dfdSAndroid Build Coastguard Worker 25*387f9dfdSAndroid Build Coastguard Workerstruct val_t { 26*387f9dfdSAndroid Build Coastguard Worker char host[80]; 27*387f9dfdSAndroid Build Coastguard Worker u64 ts; 28*387f9dfdSAndroid Build Coastguard Worker}; 29*387f9dfdSAndroid Build Coastguard WorkerBPF_HASH(start, u32, struct val_t); 30*387f9dfdSAndroid Build Coastguard Worker 31*387f9dfdSAndroid Build Coastguard Workerint do_entry(struct pt_regs *ctx) { 32*387f9dfdSAndroid Build Coastguard Worker if (!ctx->di) 33*387f9dfdSAndroid Build Coastguard Worker return 0; 34*387f9dfdSAndroid Build Coastguard Worker struct val_t val = {}; 35*387f9dfdSAndroid Build Coastguard Worker u32 pid = bpf_get_current_pid_tgid(); 36*387f9dfdSAndroid Build Coastguard Worker bpf_probe_read(&val.host, sizeof(val.host), (void *)ctx->di); 37*387f9dfdSAndroid Build Coastguard Worker val.ts = bpf_ktime_get_ns(); 38*387f9dfdSAndroid Build Coastguard Worker start.update(&pid, &val); 39*387f9dfdSAndroid Build Coastguard Worker return 0; 40*387f9dfdSAndroid Build Coastguard Worker} 41*387f9dfdSAndroid Build Coastguard Worker 42*387f9dfdSAndroid Build Coastguard Workerint do_return(struct pt_regs *ctx) { 43*387f9dfdSAndroid Build Coastguard Worker struct val_t *valp; 44*387f9dfdSAndroid Build Coastguard Worker u64 delta; 45*387f9dfdSAndroid Build Coastguard Worker u32 pid = bpf_get_current_pid_tgid(); 46*387f9dfdSAndroid Build Coastguard Worker 47*387f9dfdSAndroid Build Coastguard Worker valp = start.lookup(&pid); 48*387f9dfdSAndroid Build Coastguard Worker if (valp == 0) 49*387f9dfdSAndroid Build Coastguard Worker return 0; // missed start 50*387f9dfdSAndroid Build Coastguard Worker 51*387f9dfdSAndroid Build Coastguard Worker delta = (bpf_ktime_get_ns() - valp->ts) / 1000; 52*387f9dfdSAndroid Build Coastguard Worker bpf_trace_printk("%d %s\\n", delta, valp->host); 53*387f9dfdSAndroid Build Coastguard Worker start.delete(&pid); 54*387f9dfdSAndroid Build Coastguard Worker return 0; 55*387f9dfdSAndroid Build Coastguard Worker} 56*387f9dfdSAndroid Build Coastguard Worker""" 57*387f9dfdSAndroid Build Coastguard Workerb = BPF(text=bpf_text) 58*387f9dfdSAndroid Build Coastguard Workerb.attach_uprobe(name="c", sym="getaddrinfo", fn_name="do_entry") 59*387f9dfdSAndroid Build Coastguard Workerb.attach_uprobe(name="c", sym="gethostbyname", fn_name="do_entry") 60*387f9dfdSAndroid Build Coastguard Workerb.attach_uprobe(name="c", sym="gethostbyname2", fn_name="do_entry") 61*387f9dfdSAndroid Build Coastguard Workerb.attach_uretprobe(name="c", sym="getaddrinfo", fn_name="do_return") 62*387f9dfdSAndroid Build Coastguard Workerb.attach_uretprobe(name="c", sym="gethostbyname", fn_name="do_return") 63*387f9dfdSAndroid Build Coastguard Workerb.attach_uretprobe(name="c", sym="gethostbyname2", fn_name="do_return") 64*387f9dfdSAndroid Build Coastguard Worker 65*387f9dfdSAndroid Build Coastguard Worker# header 66*387f9dfdSAndroid Build Coastguard Workerprint("%-9s %-6s %-12s %6s %s" % ("TIME", "PID", "COMM", "LATms", "HOST")) 67*387f9dfdSAndroid Build Coastguard Worker 68*387f9dfdSAndroid Build Coastguard Worker# format output 69*387f9dfdSAndroid Build Coastguard Workerwhile 1: 70*387f9dfdSAndroid Build Coastguard Worker try: 71*387f9dfdSAndroid Build Coastguard Worker (task, pid, cpu, flags, ts, msg) = b.trace_fields() 72*387f9dfdSAndroid Build Coastguard Worker except ValueError: 73*387f9dfdSAndroid Build Coastguard Worker continue 74*387f9dfdSAndroid Build Coastguard Worker (delta, host) = msg.split(" ") 75*387f9dfdSAndroid Build Coastguard Worker deltams = int(delta) / 1000 76*387f9dfdSAndroid Build Coastguard Worker print("%-9s %-6d %-12.12s %6.2f %s" % (strftime("%H:%M:%S"), pid, task, 77*387f9dfdSAndroid Build Coastguard Worker deltams, host)) 78