NAME

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

SYNOPSIS

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

DESCRIPTION

       This tool summarizes method calls from high-level languages such as Python, Java, Ruby, and PHP.  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,  Python,  Ruby,  and
       PHP.  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,python,ruby,php}
              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)