NAME

       ssllatency.bt - Show SSL/TLS handshake latency histogram. Uses bpftrace/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, average, total latency in microseconds.  Non-zero  failed  calls  are  traced
              separately (in "@histF[]" and "@statF[]") for some functions.

       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 latency before sniffing the plaintext
       in SSL_read/write. This tool provides 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)