NAME

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

SYNOPSIS

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