ssllatency.bt(8)

1ssllatency.bt(8)            System Manager's Manual           ssllatency.bt(8)
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NAME

6       ssllatency.bt  -  Show  SSL/TLS  handshake latency histogram. Uses bpf‐
7       trace/eBPF.
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SYNOPSIS

10       ssllatency.bt
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DESCRIPTION

13       ssllatency shows latency distribution for OpenSSL handshake  functions.
14       This  is  useful  for performance analysis with different crypto cipher
15       suite, async SSL acceleration by CPU or offload device, etc.
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17       This tool works by dynamic tracing the uprobes in OpenSSL  and  related
18       crypto  libs,  and  may  need updating to match future changes to these
19       functions.
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21       Since this uses BPF, only the root user can use this tool.
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REQUIREMENTS

24       CONFIG_BPF and bpftrace.
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EXAMPLES

27       Trace SSL/TLS handshake latency, and print a histogram on Ctrl-C:
28              # ssllatency.bt
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FIELDS

31       0th    A function name is shown in  "@hist[...]"  followed  by  latency
32              histogram  and  "@stat[...]" followed by total call count, aver‐
33              age, total latency in microseconds. Non-zero  failed  calls  are
34              traced  separately (in "@histF[]" and "@statF[]") for some func‐
35              tions.
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37       1st, 2nd
38              This is a range of latency, in microseconds  (shown  in  "[...)"
39              set notation).
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41       3rd    A column showing the count of operations in this range.
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43       4th    This is an ASCII histogram representing the count column.
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OVERHEAD

46       SSL/TLS  handshake  usually  contains  network  latency  and the traced
47       crypto functions are CPU intensive tasks, so call frequency  should  be
48       low and the overhead of this tool is expected to be negligible.
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SOURCE

51       This is from bpftrace.
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53              https://github.com/iovisor/bpftrace
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55       Also  look  in  the bpftrace distribution for a companion _examples.txt
56       file containing example usage, output, and commentary for this tool.
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58       There is a bcc tool sslsniff that can show SSL/TLS handshake event  la‐
59       tency  before  sniffing the plaintext in SSL_read/write. This tool pro‐
60       vides more detailed crypto latency distribution  during  the  handshake
61       event.
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63              https://github.com/iovisor/bcc
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OS

66       Linux
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STABILITY

69       Unstable - in development.
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AUTHOR

72       Tao Xu
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