*******************************************************
* Oprofile Kernel Tree Builder                        *
*                                                     *
* Author: Ann Kilzer (akilzer@gmail.com)              *
*                                                     *  
* Created: July, 2008                                 * 
* Last Modified: August 7, 2008                       *
*******************************************************

I built this tool during my internship at Google and my host allowed me to 
release it as open source.  

This is a script for viewing the Oprofile output as a directory tree.

The script looks through the oprofile output and builds a dictionary containing 
the function names and the percentage of cpu cycles used by each. It then searches 
for the function names in the ctags output in order to determine the location 
of each function inside the kernel. Finally, the program creates a tree representing
the directory structure of the kernel. Each node represents a directory, file, or 
function, and contains the associated cpu percentage.

The program outputs a long list of nodes from each level of the tree and their 
associated cpu percentages. This uses a level order traversal sequence.



*******************************************************
* 1. Generating the ctags file                        *
*******************************************************

The following bash script will generate a ctags file while omitting certain 
directories:

-----------------------------------------------------------------------------------
#!/bin/bash

if test $# -ne 1
then
	echo "usage: $0 ARCH" 2>&1
	exit 1
fi
arch=$1

if test $arch != "full"
then
	find . -follow -name '*.[chCH]' -print | awk "\
		/\Documentation\// { next }
		/\/drivers\/s390\// { next }
		/\/include\/asm-generic\// { print }
		/\/include\/asm-$arch\// { print }
		/\/include\/asm-/ { next }
		/\/arch\/$arch\// { print }
		/\/arch\// { next }
		{ print }" > ctags.files
else
	find . -follow -name '*.[SschlyCGHL]' -print | fgrep -v "/drivers/s390/" > ctags.files
fi

ctags `cat ctags.files`
-----------------------------------------------------------------------------------

I am also working on a way to build the ctags file in python.  The file mk_tags.py
is working, but the output is not identical to that produced by the bash script.


*******************************************************
* 2. Generating the oprofile output:                  *
*******************************************************

The oprofile output must have the columns set up as shown below: 

	Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a 
		unit mask or 0x00 (unhalted core cycles) count 100000

	samples	%	image name	app name	symbol name
	...	...	...		...		...



The following commands should do the trick:
-----------------------------------------------------------------------------------
opcontrol --vmlinux= [path to linux kernel]
opcontrol --separate=kernel
opcontrol --reset
opcontrol -s

====>>>> command to run

opcontrol --shutdown
opreport --merge all -l -p /lib/modules/`uname -r` -p [path to linux kernel]
>oprofile.all.$i
opreport --merge all -l -p /lib/modules/`uname -r` -p [path to linux kernel]
<command> >oprofile.directio.$i
-----------------------------------------------------------------------------------

*******************************************************
* 3. Running the script	               	              *
*******************************************************
This is a preliminary version of a script for parsing the oprofile output.

This version does not generate the ctags file, though I have included a bash
script that does.  I am also working on a python script to generate ctags.
The oprofile output and the ctags file must be passed via the command line as
shown:

  $ python treeprint.py -f <oprofile output> -t <ctags file> -p <path to kernel> [-b bound]

The bound is optional.  The rest of the parameters are required.

The script looks through the oprofile output and builds a dictionary containing
the function names and the percentage of cpu cycles used by each.  It then
searches for the function names in the ctags output in order to determine the
location of each function inside the kernel.  Finally, the program creates a
tree representing the directory structure of the kernel.  Each node represents a
directory, file, or function, and contains the associated cpu percentage.

The program outputs a long list of nodes from each level of the tree and their
associated cpu percentages.  This uses a level order traversal sequence.  A
later version may incorporate a graphical output.


TODO: add sample tags file, oprofile output, and output