ssllatency.bt(8) System Manager's Manual ssllatency.bt(8)
NAME
ssllatency.bt - Show SSL/TLS handshake latency histogram. Uses bpf-
trace/eBPF.
SYNOPSIS
ssllatency.bt
DESCRIPTION
ssllatency shows latency distribution for OpenSSL handshake functions.
This is useful for performance analysis with different crypto cipher
suite, async SSL acceleration by CPU or offload device, etc.
This tool works by dynamic tracing the uprobes in OpenSSL and related
crypto libs, and may need updating to match future changes to these
functions.
Since this uses BPF, only the root user can use this tool.
REQUIREMENTS
CONFIG_BPF and bpftrace.
EXAMPLES
Trace SSL/TLS handshake latency, and print a histogram on Ctrl-C:
# ssllatency.bt
FIELDS
0th A function name is shown in "@hist[...]" followed by latency
histogram and "@stat[...]" followed by total call count, aver-
age, total latency in microseconds. Non-zero failed calls are
traced separately (in "@histF[]" and "@statF[]") for some func-
tions.
1st, 2nd
This is a range of latency, in microseconds (shown in "[...)"
set notation).
3rd A column showing the count of operations in this range.
4th This is an ASCII histogram representing the count column.
OVERHEAD
SSL/TLS handshake usually contains network latency and the traced
crypto functions are CPU intensive tasks, so call frequency should be
low and the overhead of this tool is expected to be negligible.
SOURCE
This is from bpftrace.
https://github.com/iovisor/bpftrace
Also look in the bpftrace distribution for a companion _examples.txt
file containing example usage, output, and commentary for this tool.
There is a bcc tool sslsniff that can show SSL/TLS handshake event la-
tency before sniffing the plaintext in SSL_read/write. This tool pro-
vides more detailed crypto latency distribution during the handshake
event.
https://github.com/iovisor/bcc
OS
Linux
STABILITY
Unstable - in development.
AUTHOR
Tao Xu
SEE ALSO
sslsnoop.bt(8)
USER COMMANDS 2021-12-28 ssllatency.bt(8)
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