#!/usr/bin/env bpftrace
/*
* gethostlatency Trace getaddrinfo/gethostbyname[2] calls.
* For Linux, uses bpftrace and eBPF.
*
* 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.
*
* USAGE: gethostlatency.bt
*
* This is a bpftrace version of the bcc tool of the same name.
*
* Copyright 2018 Netflix, Inc.
* Licensed under the Apache License, Version 2.0 (the "License")
*
* 08-Sep-2018 Brendan Gregg Created this.
*/
BEGIN
{
printf("Tracing getaddr/gethost calls... Hit Ctrl-C to end.\n");
printf("%-9s %-6s %-16s %6s %s\n", "TIME", "PID", "COMM", "LATms",
"HOST");
}
uprobe:libc:getaddrinfo,
uprobe:libc:gethostbyname,
uprobe:libc:gethostbyname2
{
@start[tid] = nsecs;
@name[tid] = arg0;
}
uretprobe:libc:getaddrinfo,
uretprobe:libc:gethostbyname,
uretprobe:libc:gethostbyname2
/@start[tid]/
{
$latms = (nsecs - @start[tid]) / 1e6;
time("%H:%M:%S ");
printf("%-6d %-16s %6d %s\n", pid, comm, $latms, str(@name[tid]));
delete(@start[tid]);
delete(@name[tid]);
}
Mini Shell