NAME

       uflow,  javaflow,  pythonflow,  rubyflow,  phpflow - Print a flow graph of method calls in
       high-level languages.

SYNOPSIS

       javaflow [-h] [-M METHOD] [-C CLAZZ] [-v] pid
       pythonflow [-h] [-M METHOD] [-C CLAZZ] [-v] pid
       rubyflow [-h] [-M METHOD] [-C CLAZZ] [-v] pid
       phpflow [-h] [-M METHOD] [-C CLAZZ] [-v] pid
       uflow [-h] [-M METHOD] [-C CLAZZ] [-v] [-l {java,python,ruby,php}] pid

DESCRIPTION

       uflow traces method calls and prints them in a flow graph that  can  facilitate  debugging
       and diagnostics by following the program's execution (method flow).

       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 processes, the startup  flag  "-XX:+ExtendedDTraceProbes"  is
       required. 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

       -M METHOD
              Print only method calls where the method name begins with this string.

       -C CLAZZ
              Print  only  method  calls  where the class name begins with this string. The class
              name interpretation strongly depends on the language.  For  example,  in  Java  use
              "package/subpackage/ClassName" to refer to classes.

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

       {java,python,ruby,php}
              The language to trace.

       pid    The process id to trace.

EXAMPLES

       Follow method flow in a Ruby process:
              # uflow ruby 148

       Follow method flow in a Java process where the class name is java.lang.Thread:
              # uflow -C java/lang/Thread java 1802

FIELDS

       CPU    The  CPU number on which the method was invoked. This is useful to easily see where
              the output skips to a different CPU.

       PID    The process id.

       TID    The thread id.

       TIME   The duration of the method call.

       METHOD The method name.

OVERHEAD

       This tool has extremely high overhead because  it  prints  every  method  call.  For  some
       scenarios,  you might see lost samples in the output as the tool is unable to keep up with
       the rate of data coming from the kernel. Filtering by class  or  method  prefix  can  help
       reduce  the  amount  of  data  printed,  but  there  is  still a very high overhead in the
       collection mechanism. Do not use for  performance-  sensitive  production  scenarios,  and
       always test first.

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

       trace(8), ustat(8)