Manual: javaflow-bpfcc

uflow(8)					   System Manager's Manual					    uflow(8)

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:+Ex‐
       tendedDTraceProbes" 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 dif‐
	      ferent 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)

USER COMMANDS						 2018-10-09						    uflow(8)