#!/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]); }