NAME

       ucalls,  javacalls,  perlcalls,  phpcalls, pythoncalls, rubycalls, tclcalls - Summarize method calls from
       high-level languages and Linux syscalls.

SYNOPSIS

       javacalls [-h] [-T TOP] [-L] [-S] [-v] [-m] pid [interval]
       perlcalls [-h] [-T TOP] [-L] [-S] [-v] [-m] pid [interval]
       phpcalls [-h] [-T TOP] [-L] [-S] [-v] [-m] pid [interval]
       pythoncalls [-h] [-T TOP] [-L] [-S] [-v] [-m] pid [interval]
       rubycalls [-h] [-T TOP] [-L] [-S] [-v] [-m] pid [interval]
       tclcalls [-h] [-T TOP] [-L] [-S] [-v] [-m] pid [interval]
       ucalls [-l {java,perl,php,python,ruby}] [-h] [-T TOP] [-L] [-S] [-v] [-m] pid [interval]

DESCRIPTION

       This tool summarizes method calls from high-level languages such as Java, Perl, PHP,  Python,  Ruby,  and
       Tcl.  It  can  also trace Linux system calls. Whenever a method is invoked, ucalls records the call count
       and optionally the method's execution time (latency) and displays a summary.

       This uses in-kernel eBPF maps to store per process summaries for efficiency.

       This tool relies on USDT probes embedded in many high-level languages, such as Java, Perl,  PHP,  Python,
       Ruby,  and  Tcl.  It  requires  a  runtime  instrumented  with these probes, which in some cases requires
       building from source with a USDT-specific flag, such as "--enable-dtrace" or "--with-dtrace".  For  Java,
       method  probes  are  not  enabled  by  default, and can be turned on by running the Java process with the
       "-XX:+ExtendedDTraceProbes" flag. For PHP processes, the environment variable USE_ZEND_DTRACE must be set
       to 1.

       Since this uses BPF, only the root user can use this tool.

REQUIREMENTS

       CONFIG_BPF and bcc.

OPTIONS

       -l {java,perl,php,python,ruby,tcl}
              The language to trace. If not provided, only syscalls are traced (when the -S option is used).

       -T TOP Print only the top methods by frequency or latency.

       -L     Collect method invocation latency (duration).

       -S     Collect Linux syscalls frequency and timing.

       -v     Print the resulting BPF program, for debugging purposes.

       -m     Print times in milliseconds (the default is microseconds).

       pid    The process id to trace.

       interval
              Print summary after this number of  seconds  and  then  exit.  By  default,  wait  for  Ctrl+C  to
              terminate.

EXAMPLES

       Trace the top 10 Ruby method calls:
              # ucalls -T 10 -l ruby 1344

       Trace Python method calls and Linux syscalls including latency in milliseconds:
              # ucalls -l python -mL 2020

       Trace only syscalls and print a summary after 10 seconds:
              # ucalls -S 788 10

OVERHEAD

       Tracing  individual  method  calls  will produce a considerable overhead in all high-level languages. For
       languages with just-in-time compilation, such as Java, the overhead can be  more  considerable  than  for
       interpreted  languages.   On  the  other  hand,  syscall  tracing  will  typically  be tolerable for most
       processes, unless they have a very unusual rate of system calls.

SOURCE

       This is from bcc.

              https://github.com/iovisor/bcc

       Also look in the bcc distribution for a companion _example.txt file containing example usage, output, and
       commentary for this tool.

OS

       Linux

STABILITY

       Unstable - in development.

AUTHOR

       Sasha Goldshtein

SEE ALSO

       ustat(8), argdist(8)

USER COMMANDS                                      2018-10-09                                          ucalls(8)