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migrated gethostlatency to use bpf_perf_event
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#!/usr/bin/python | ||
# | ||
# gethostlatency Show latency for getaddrinfo/gethostbyname[2] calls. | ||
# For Linux, uses BCC, eBPF. Embedded C. | ||
# | ||
# This can be useful for identifying DNS latency, by identifying which | ||
# remote host name lookups were slow, and by how much. | ||
# | ||
# This uses dynamic tracing of user-level functions and registers, and may | ||
# need modifications to match your software and processor architecture. | ||
# | ||
# Copyright 2016 Netflix, Inc. | ||
# Licensed under the Apache License, Version 2.0 (the "License") | ||
# | ||
# 28-Jan-2016 Brendan Gregg Created this. | ||
|
||
from __future__ import print_function | ||
from bcc import BPF | ||
from time import strftime | ||
|
||
# load BPF program | ||
bpf_text = """ | ||
#include <uapi/linux/ptrace.h> | ||
struct val_t { | ||
char host[80]; | ||
u64 ts; | ||
}; | ||
BPF_HASH(start, u32, struct val_t); | ||
int do_entry(struct pt_regs *ctx) { | ||
if (!ctx->di) | ||
return 0; | ||
struct val_t val = {}; | ||
u32 pid = bpf_get_current_pid_tgid(); | ||
bpf_probe_read(&val.host, sizeof(val.host), (void *)ctx->di); | ||
val.ts = bpf_ktime_get_ns(); | ||
start.update(&pid, &val); | ||
return 0; | ||
} | ||
int do_return(struct pt_regs *ctx) { | ||
struct val_t *valp; | ||
u64 delta; | ||
u32 pid = bpf_get_current_pid_tgid(); | ||
valp = start.lookup(&pid); | ||
if (valp == 0) | ||
return 0; // missed start | ||
delta = (bpf_ktime_get_ns() - valp->ts) / 1000; | ||
bpf_trace_printk("%d %s\\n", delta, valp->host); | ||
start.delete(&pid); | ||
return 0; | ||
} | ||
""" | ||
b = BPF(text=bpf_text) | ||
b.attach_uprobe(name="c", sym="getaddrinfo", fn_name="do_entry") | ||
b.attach_uprobe(name="c", sym="gethostbyname", fn_name="do_entry") | ||
b.attach_uprobe(name="c", sym="gethostbyname2", fn_name="do_entry") | ||
b.attach_uretprobe(name="c", sym="getaddrinfo", fn_name="do_return") | ||
b.attach_uretprobe(name="c", sym="gethostbyname", fn_name="do_return") | ||
b.attach_uretprobe(name="c", sym="gethostbyname2", fn_name="do_return") | ||
|
||
# header | ||
print("%-9s %-6s %-12s %6s %s" % ("TIME", "PID", "COMM", "LATms", "HOST")) | ||
|
||
# format output | ||
while 1: | ||
try: | ||
(task, pid, cpu, flags, ts, msg) = b.trace_fields() | ||
except ValueError: | ||
continue | ||
(delta, host) = msg.split(" ") | ||
deltams = int(delta) / 1000 | ||
print("%-9s %-6d %-12.12s %6.2f %s" % (strftime("%H:%M:%S"), pid, task, | ||
deltams, host)) |