48 lines
1.2 KiB
Plaintext
Executable File
48 lines
1.2 KiB
Plaintext
Executable File
#!/usr/bin/env bpftrace
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/*
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* gethostlatency Trace getaddrinfo/gethostbyname[2] calls.
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* For Linux, uses bpftrace and eBPF.
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*
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* This can be useful for identifying DNS latency, by identifying which
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* remote host name lookups were slow, and by how much.
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*
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* This uses dynamic tracing of user-level functions and registers, and may
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# need modifications to match your software and processor architecture.
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*
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* USAGE: gethostlatency.bt
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*
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* This is a bpftrace version of the bcc tool of the same name.
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*
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* Copyright 2018 Netflix, Inc.
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* Licensed under the Apache License, Version 2.0 (the "License")
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*
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* 08-Sep-2018 Brendan Gregg Created this.
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*/
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BEGIN
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{
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printf("Tracing getaddr/gethost calls... Hit Ctrl-C to end.\n");
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printf("%-9s %-6s %-16s %6s %s\n", "TIME", "PID", "COMM", "LATms",
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"HOST");
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}
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uprobe:libc:getaddrinfo,
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uprobe:libc:gethostbyname,
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uprobe:libc:gethostbyname2
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{
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@start[tid] = nsecs;
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@name[tid] = arg0;
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}
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uretprobe:libc:getaddrinfo,
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uretprobe:libc:gethostbyname,
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uretprobe:libc:gethostbyname2
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/@start[tid]/
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{
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$latms = (nsecs - @start[tid]) / 1e6;
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time("%H:%M:%S ");
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printf("%-6d %-16s %6d %s\n", pid, comm, $latms, str(@name[tid]));
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delete(@start[tid]);
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delete(@name[tid]);
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}
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