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)