perf tools: Add example call-graph script

Add a script to produce a call-graph from data exported to a postgresql
database and derived from a processor trace event like intel_pt or intel_bts.

Refer to comments in the scripts call-graph-from-postgresql.py and
export-to-postgresql.py for more details on how to set up the environment,
install the required packages, etc.

Committer note:

From the scripts, for convenience while reading 'git log':

  An example of using this script with Intel PT:

  $ perf record -e intel_pt//u ls
  $ perf script -s ~/libexec/perf-core/scripts/python/export-to-postgresql.py pt_example branches calls
  2015-05-29 12:49:23.464364 Creating database...
  2015-05-29 12:49:26.281717 Writing to intermediate files...
  2015-05-29 12:49:27.190383 Copying to database...
  2015-05-29 12:49:28.140451 Removing intermediate files...
  2015-05-29 12:49:28.147451 Adding primary keys
  2015-05-29 12:49:28.655683 Adding foreign keys
  2015-05-29 12:49:29.365350 Done
  $ python tools/perf/scripts/python/call-graph-from-postgresql.py pt_example
  # The result is a GUI window with a tree representing a context-sensitive
  # call-graph.  Expanding a couple of levels of the tree and adjusting column
  # widths to suit will display something like:

                                         Call Graph: pt_example
  Call Path                        |Object     |Count|Time(ns)|Time(%)|Branch Count|Branch Count(%)
  v- ls
     v- 2638:2638
         v- _start                  ld-2.19.so    1   10074071  100.0        211135          100.0
           |- unknown               unknown       1      13198    0.1             1            0.0
           >- _dl_start             ld-2.19.so    1    1400980   13.9         19637            9.3
           >- _d_linit_internal     ld-2.19.so    1     448152    4.4         11094            5.3
           v-__libc_start_main@plt  ls            1    8211741   81.5        180397           85.4
              >- _dl_fixup          ld-2.19.so    1       7607    0.1           108            0.1
              >- __cxa_atexit       libc-2.19.so  1      11737    0.1            10            0.0
              >- __libc_csu_init    ls            1      10354    0.1            10            0.0
              |- _setjmp            libc-2.19.so  1          0    0.0             4            0.0
              v- main               ls            1    8182043   99.6        180254           99.9
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-11-git-send-email-adrian.hunter@intel.com
[ Added 'python-pyside qt-postgresql' to the yum cmdline installing required packages ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/scripts/python/export-to-postgresql.py

@@ -15,6 +15,53 @@ import sys
 import struct
 import datetime
 
+# To use this script you will need to have installed package python-pyside which
+# provides LGPL-licensed Python bindings for Qt.  You will also need the package
+# libqt4-sql-psql for Qt postgresql support.
+#
+# The script assumes postgresql is running on the local machine and that the
+# user has postgresql permissions to create databases. Examples of installing
+# postgresql and adding such a user are:
+#
+# fedora:
+#
+#	$ sudo yum install postgresql postgresql-server python-pyside qt-postgresql
+#	$ sudo su - postgres -c initdb
+#	$ sudo service postgresql start
+#	$ sudo su - postgres
+#	$ createuser <your user id here>
+#	Shall the new role be a superuser? (y/n) y
+#
+# ubuntu:
+#
+#	$ sudo apt-get install postgresql
+#	$ sudo su - postgres
+#	$ createuser <your user id here>
+#	Shall the new role be a superuser? (y/n) y
+#
+# An example of using this script with Intel PT:
+#
+#	$ perf record -e intel_pt//u ls
+#	$ perf script -s ~/libexec/perf-core/scripts/python/export-to-postgresql.py pt_example branches calls
+#	2015-05-29 12:49:23.464364 Creating database...
+#	2015-05-29 12:49:26.281717 Writing to intermediate files...
+#	2015-05-29 12:49:27.190383 Copying to database...
+#	2015-05-29 12:49:28.140451 Removing intermediate files...
+#	2015-05-29 12:49:28.147451 Adding primary keys
+#	2015-05-29 12:49:28.655683 Adding foreign keys
+#	2015-05-29 12:49:29.365350 Done
+#
+# To browse the database, psql can be used e.g.
+#
+#	$ psql pt_example
+#	pt_example=# select * from samples_view where id < 100;
+#	pt_example=# \d+
+#	pt_example=# \d+ samples_view
+#	pt_example=# \q
+#
+# An example of using the database is provided by the script
+# call-graph-from-postgresql.py.  Refer to that script for details.
+
 from PySide.QtSql import *
 
 # Need to access PostgreSQL C library directly to use COPY FROM STDIN