Added Python 3 support while keeping Python 2.7 compatibility.

Committer notes:

This doesn't make it to auto detect python 3, one has to explicitely ask
it to build with python 3 devel files, here are the instructions
provided by Jaroslav:

 ---
  $ cp -a tools/perf tools/python3-perf
  $ make V=1 prefix=/usr -C tools/perf PYTHON=/usr/bin/python2 all
  $ make V=1 prefix=/usr -C tools/python3-perf PYTHON=/usr/bin/python3 all
  $ make V=1 prefix=/usr -C tools/python3-perf PYTHON=/usr/bin/python3 DESTDIR=%{buildroot} install-python_ext
  $ make V=1 prefix=/usr -C tools/perf PYTHON=/usr/bin/python2 DESTDIR=%{buildroot} install-python_ext
 ---

We need to make this automatic, just like the existing tests for checking if
the python2 devel files are in place, allowing the build with python3 if
available, fallbacking to python2 and then just disabling it if none are
available.

So, using the PYTHON variable to build it using O= we get:

Before this patch:

  $ rpm -q python3 python3-devel
  python3-3.6.4-7.fc27.x86_64
  python3-devel-3.6.4-7.fc27.x86_64
  $ rm -rf /tmp/build/perf/ ; mkdir -p /tmp/build/perf ; make O=/tmp/build/perf PYTHON=/usr/bin/python3 -C tools/perf install-bin
  make: Entering directory '/home/acme/git/linux/tools/perf'
  <SNIP>
  Makefile.config:670: Python 3 is not yet supported; please set
  Makefile.config:671: PYTHON and/or PYTHON_CONFIG appropriately.
  Makefile.config:672: If you also have Python 2 installed, then
  Makefile.config:673: try something like:
  Makefile.config:674:
  Makefile.config:675:   make PYTHON=python2
  Makefile.config:676:
  Makefile.config:677: Otherwise, disable Python support entirely:
  Makefile.config:678:
  Makefile.config:679:   make NO_LIBPYTHON=1
  Makefile.config:680:
  Makefile.config:681: *** .  Stop.
  make[1]: *** [Makefile.perf:212: sub-make] Error 2
  make: *** [Makefile:110: install-bin] Error 2
  make: Leaving directory '/home/acme/git/linux/tools/perf'
  $

After:

  $ make O=/tmp/build/perf PYTHON=python3 -C tools/perf install-bin
  $ ldd ~/bin/perf | grep python
	libpython3.6m.so.1.0 => /lib64/libpython3.6m.so.1.0 (0x00007f58a31e8000)
  $ rpm -qf /lib64/libpython3.6m.so.1.0
  python3-libs-3.6.4-7.fc27.x86_64
  $

Now verify that when using the binding the right ELF file is loaded,
using perf trace:

  $ perf trace -e open* perf test python
     0.051 ( 0.016 ms): perf/3927 openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC           ) = 3
<SNIP>
  18: 'import perf' in python                               :
     8.849 ( 0.013 ms): sh/3929 openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC           ) = 3
<SNIP>
    25.572 ( 0.008 ms): python3/3931 openat(dfd: CWD, filename: /tmp/build/perf/python/perf.cpython-36m-x86_64-linux-gnu.so, flags: CLOEXEC) = 3
<SNIP>
 Ok
<SNIP>
  $

And using tools/perf/python/twatch.py, to show PERF_RECORD_ metaevents:

  $ python3 tools/perf/python/twatch.py
  cpu: 3, pid: 16060, tid: 16060 { type: fork, pid: 5207, ppid: 16060, tid: 5207, ptid: 16060, time: 10798513015459}
  cpu: 3, pid: 16060, tid: 16060 { type: fork, pid: 5208, ppid: 16060, tid: 5208, ptid: 16060, time: 10798513562503}
  cpu: 0, pid: 5208, tid: 5208 { type: comm, pid: 5208, tid: 5208, comm: grep }
  cpu: 2, pid: 5207, tid: 5207 { type: comm, pid: 5207, tid: 5207, comm: ps }
  cpu: 2, pid: 5207, tid: 5207 { type: exit, pid: 5207, ppid: 5207, tid: 5207, ptid: 5207, time: 10798551337484}
  cpu: 3, pid: 5208, tid: 5208 { type: exit, pid: 5208, ppid: 5208, tid: 5208, ptid: 5208, time: 10798551292153}
  cpu: 3, pid: 601, tid: 601 { type: fork, pid: 5209, ppid: 601, tid: 5209, ptid: 601, time: 10801779977324}
  ^CTraceback (most recent call last):
    File "tools/perf/python/twatch.py", line 68, in <module>
      main()
    File "tools/perf/python/twatch.py", line 40, in main
      evlist.poll(timeout = -1)
  KeyboardInterrupt
  $

  # ps ax|grep twatch
 5197 pts/8    S+     0:00 python3 tools/perf/python/twatch.py
  # ls -la /proc/5197/smaps
  -r--r--r--. 1 acme acme 0 Feb 19 13:14 /proc/5197/smaps
  # grep python /proc/5197/smaps
  558111307000-558111309000 r-xp 00000000 fd:00 3151710  /usr/bin/python3.6
  558111508000-558111509000 r--p 00001000 fd:00 3151710  /usr/bin/python3.6
  558111509000-55811150a000 rw-p 00002000 fd:00 3151710  /usr/bin/python3.6
  7ffad6fc1000-7ffad7008000 r-xp 00000000 00:2d 220196   /tmp/build/perf/python/perf.cpython-36m-x86_64-linux-gnu.so
  7ffad7008000-7ffad7207000 ---p 00047000 00:2d 220196   /tmp/build/perf/python/perf.cpython-36m-x86_64-linux-gnu.so
  7ffad7207000-7ffad7208000 r--p 00046000 00:2d 220196   /tmp/build/perf/python/perf.cpython-36m-x86_64-linux-gnu.so
  7ffad7208000-7ffad7215000 rw-p 00047000 00:2d 220196   /tmp/build/perf/python/perf.cpython-36m-x86_64-linux-gnu.so
  7ffadea77000-7ffaded3d000 r-xp 00000000 fd:00 3151795  /usr/lib64/libpython3.6m.so.1.0
  7ffaded3d000-7ffadef3c000 ---p 002c6000 fd:00 3151795  /usr/lib64/libpython3.6m.so.1.0
  7ffadef3c000-7ffadef42000 r--p 002c5000 fd:00 3151795  /usr/lib64/libpython3.6m.so.1.0
  7ffadef42000-7ffadefa5000 rw-p 002cb000 fd:00 3151795  /usr/lib64/libpython3.6m.so.1.0
  #

And with this patch, but building normally, without specifying the
PYTHON=python3 part, which will make it use python2 if its devel files are
available, like in this test:

  $ make O=/tmp/build/perf -C tools/perf install-bin
  $ ldd ~/bin/perf | grep python
	libpython2.7.so.1.0 => /lib64/libpython2.7.so.1.0 (0x00007f6a44410000)
  $ ldd /tmp/build/perf/python_ext_build/lib/perf.so  | grep python
	libpython2.7.so.1.0 => /lib64/libpython2.7.so.1.0 (0x00007fed28a2c000)
  $

  [acme@jouet perf]$ tools/perf/python/twatch.py
  cpu: 0, pid: 2817, tid: 2817 { type: fork, pid: 2817, ppid: 2817, tid: 8910, ptid: 2817, time: 11126454335306}
  cpu: 0, pid: 2817, tid: 2817 { type: comm, pid: 2817, tid: 8910, comm: worker }
  $ ps ax | grep twatch.py
   8909 pts/8    S+     0:00 /usr/bin/python tools/perf/python/twatch.py
  $ grep python /proc/8909/smaps
  5579de658000-5579de659000 r-xp 00000000 fd:00 3156044  /usr/bin/python2.7
  5579de858000-5579de859000 r--p 00000000 fd:00 3156044  /usr/bin/python2.7
  5579de859000-5579de85a000 rw-p 00001000 fd:00 3156044  /usr/bin/python2.7
  7f0de01f7000-7f0de023e000 r-xp 00000000 00:2d 230695   /tmp/build/perf/python/perf.so
  7f0de023e000-7f0de043d000 ---p 00047000 00:2d 230695   /tmp/build/perf/python/perf.so
  7f0de043d000-7f0de043e000 r--p 00046000 00:2d 230695   /tmp/build/perf/python/perf.so
  7f0de043e000-7f0de044b000 rw-p 00047000 00:2d 230695   /tmp/build/perf/python/perf.so
  7f0de6f0f000-7f0de6f13000 r-xp 00000000 fd:00 134975   /usr/lib64/python2.7/lib-dynload/_localemodule.so
  7f0de6f13000-7f0de7113000 ---p 00004000 fd:00 134975   /usr/lib64/python2.7/lib-dynload/_localemodule.so
  7f0de7113000-7f0de7114000 r--p 00004000 fd:00 134975   /usr/lib64/python2.7/lib-dynload/_localemodule.so
  7f0de7114000-7f0de7115000 rw-p 00005000 fd:00 134975   /usr/lib64/python2.7/lib-dynload/_localemodule.so
  7f0de7e73000-7f0de8052000 r-xp 00000000 fd:00 3173292  /usr/lib64/libpython2.7.so.1.0
  7f0de8052000-7f0de8251000 ---p 001df000 fd:00 3173292  /usr/lib64/libpython2.7.so.1.0
  7f0de8251000-7f0de8255000 r--p 001de000 fd:00 3173292  /usr/lib64/libpython2.7.so.1.0
  7f0de8255000-7f0de8291000 rw-p 001e2000 fd:00 3173292  /usr/lib64/libpython2.7.so.1.0
  $
Signed-off-by: NJaroslav Škarvada <jskarvad@redhat.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
LPU-Reference: 20180119205641.24242-1-jskarvad@redhat.com
Link: https://lkml.kernel.org/n/tip-8d7dt9kqp83vsz25hagug8fu@git.kernel.org
[ Removed explicit check for python version, allowing it to really build with python3 ]
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

The -spec=/path/to/file can be used to change what gcc puts in the cc,
ld, etc command lines, but this is not present in clang, filter it out
at the setup.py file by changing python2's internal variable where it
keeps its initial CFLAGS value.

With this all of perf can be built in at least Fedora 25, fixing this
problem:

    GEN      /tmp/build/perf/python/perf.so
    CC       /tmp/build/perf/builtin-buildid-list.o
  clang-4.0: error: argument unused during compilation: '-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1' [-Werror,-Wunused-command-line-argument]
  clang-4.0: error: argument unused during compilation: '-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1' [-Werror,-Wunused-command-line-argument]
  error: command 'clang' failed with exit status 1

Now I need to change all the containers where I have clang to build
perf with it, so that we can check that in other distros (opensuse, debian,
ubuntu, etc) this also works.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-g9lhgr162ao8ao29vvf0hgm1@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

The util/python-ext-sources file contains source files required to build
the python extension relative to $(srctree)/tools/perf,

Such a file path $(FILE).c is handed over to the python extension build
system, which builds the final object in the
$(PYTHON_EXTBUILD)/tmp/$(FILE).o path.

After the build is done all files from $(PYTHON_EXTBUILD)lib/ are
carried as the result binaries.

Above system fails when we add source file relative to ../lib, which we
do for:

  ../lib/bitmap.c
  ../lib/find_bit.c
  ../lib/hweight.c
  ../lib/rbtree.c

All above objects will be built like:

  $(PYTHON_EXTBUILD)/tmp/../lib/bitmap.c
  $(PYTHON_EXTBUILD)/tmp/../lib/find_bit.c
  $(PYTHON_EXTBUILD)/tmp/../lib/hweight.c
  $(PYTHON_EXTBUILD)/tmp/../lib/rbtree.c

which accidentally happens to be final library path:

  $(PYTHON_EXTBUILD)/lib/

Changing setup.py to pass full paths of source files to Extension build
class and thus keep all built objects under $(PYTHON_EXTBUILD)tmp
directory.
Reported-by: NJeff Bastian <jbastian@redhat.com>
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Tested-by: NJosh Boyer <jwboyer@fedoraproject.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: stable@vger.kernel.org # v4.2+
Link: http://lkml.kernel.org/r/20160227201350.GB28494@krava.redhat.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Renaming libapikfs.a to libapi.a, because it's not just 'fs' specific
library now.
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Tested-by: NSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Tested-by: NWill Deacon <will.deacon@arm.com>
Cc: Alexis Berlemont <alexis.berlemont@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-g1mk5oj2ayq4vn653ovfg3gv@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Move debugfs.* to api/fs/. We have a common tools/lib/api/ place where
the Makefile lives and then we place the headers in subdirs.

For example, all the fs-related stuff goes to tools/lib/api/fs/ from
which we get libapikfs.a (acme got almost the naming he wanted :-)) and
we link it into the tools which need it - in this case perf and
tools/vm/page-types.

acme:

"Looking at the implementation, I think some tools can even link
directly to the .o files, avoiding the .a file altogether.

But that is just an optimization/finer granularity tools/lib/
cherrypicking that toolers can make use of."

Fixup documentation cleaning target while at it.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NIngo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stanislav Fomichev <stfomichev@yandex-team.ru>
Cc: Stephane Eranian <eranian@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1386605664-24041-2-git-send-email-bp@alien8.deSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Merging all *CFLAGS* make variable into CFLAGS to eliminate all special
*_CFLAGS_* variables and make the setup clear.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1369398928-9809-19-git-send-email-jolsa@redhat.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

This introduces the tools/lib/lk library, that will gradually have the
routines that now are used in tools/perf/ and other tools and that can
be shared.

Start by carving out debugfs routines for general use.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1361374353-30385-5-git-send-email-bp@alien8.de
[ committer note: Add tools/lib/lk/ to perf's MANIFEST so that its tarballs continue to build ]
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Namhyung Kim reported that the build fails with:

  GEN python/perf.so
  gcc: error: python_ext_build/tmp//../../libtraceevent.a: No such file or directory
  error: command 'gcc' failed with exit status 1
  cp: cannot stat `python_ext_build/lib/perf.so': No such file or directory
  make: *** [python/perf.so] Error 1

We need to propagate the TE_PATH variable to the setup.py file.
Reported-by: NNamhyung Kim <namhyung@kernel.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/n/tip-8umiPbm4sxpknKivbjgykhut@git.kernel.org
[ Fixed superfluous variable build error. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

The evsel methods to read tracepoint fields uses libtraceevent
functions, becoming needed by the python binding as well.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-j3o4v7jyvp9ke9n230l96a1m@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

The perf python extention (perf.so) file lacks its dependencies in the
Makefile so that it cannot be refreshed if one of source files it depends
is changed. Fix it by putting them in a separate file and processing it in
both of Makefile and setup.py.
Reported-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1329043524-12470-1-git-send-email-namhyung@gmail.comSigned-off-by: NNamhyung Kim <namhyung@gmail.com>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Convenient way of asking for tracepoint events to be added to an
existing evlist.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-0ylj4wrg54791u0baqb9swbb@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Adding install-python_ext target to install python extension related
files.  Installation directory is governed by python distutils package
and follows the DESTDIR variable settings.

Also moving python extension build output into '$(O)python_ext_build'
directory and making it configurable via PYTHON_EXTBUILD variable.

Keeping the '$(O)python/perf.so' file, so it could be used for testing
as of until now.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110722113307.GA1931@jolsa.brq.redhat.comSigned-off-by: NJiri Olsa <jolsa@redhat.com>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Fix the following build error:

     GEN python/perf.so
 In file included from util/evsel.h:10,
                  from util/python.c:6:
 util/hist.h:106:18: error: newt.h: No such file or directory
 error: command 'x86_64-pc-linux-gnu-gcc' failed with exit status 1
 make: *** [python/perf.so] Error 1

by passing BASIC_CFLAGS to setup.py. BASIC_CFLAGS variable contains
the -DNO_NEWT_SUPPORT switch which prevents building python c
extension with newt.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <20110329180236.GA19366@erda.amd.com>
Signed-off-by: NRobert Richter <robert.richter@amd.com>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

The 023695d9 cset added a new file, util/cgroup.c, that is referenced from
util/evsel.c, so it needs to be present in util/setup.py so that the python
shared object binding works, fixing this:

[root@emilia linux]# export PYTHONPATH=~acme/git/build/perf/python/
[root@emilia linux]# ./tools/perf/python/twatch.py
Traceback (most recent call last):
  File "./tools/perf/python/twatch.py", line 16, in <module>
    import perf
ImportError: /home/acme/git/build/perf/python/perf.so: undefined symbol: close_cgroup

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Where there are lots of errors related to python methods receiving
'char *' for things like file open mode, which break the build, also
disable strict aliasing and fixup some other warnings. Now builds on
both 32-bit and 64-bit fedora systems.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

First clarifying that this kind of binding is not a replacement or an
equivalent to the 'perf script' way of using python with perf.

The 'perf script' way is to process events and look at a given script
for some python function that matches the events to pass each event for
processing.

This is a python module, i.e. everything is driven from the python
script, that merely uses "import perf" or "from perf import".

perf script is focused on tracepoints, this binding is focused on profiling as
an initial target. More work is needed to make available tracepoint specific
variables as event variables accessible via this binding.

There is one example of such usage model, in
tools/perf/python/twatch.py, a tool to watch "cycles" events together
with task (fork, exit) and comm perf events.

For now, due to me not being able to grok how python distutils cope with
building C extensions outside the sources dir the install target just
builds it, I'm using it as:

[root@emilia linux]# export PYTHONPATH=~acme/git/build/perf/lib.linux-x86_64-2.6/
[root@emilia linux]# tools/perf/python/twatch.py
cpu:  4, pid: 30126, tid: 30126 { type: mmap, pid: 30126, tid: 30126, start: 0x4, length: 0x82e9ca03, offset: 0, filename:  }
cpu:  6, pid:   47, tid:   47 { type: mmap, pid: 47, tid: 47, start: 0x6, length: 0xbef87c36, offset: 0, filename:  }
cpu:  1, pid:    0, tid:    0 { type: mmap, pid: 0, tid: 0, start: 0x1, length: 0x775d1904, offset: 0, filename:  }
cpu:  7, pid:    0, tid:    0 { type: mmap, pid: 0, tid: 0, start: 0x7, length: 0xc750aeb6, offset: 0, filename:  }
cpu:  5, pid: 2255, tid: 2255 { type: mmap, pid: 2255, tid: 2255, start: 0x5, length: 0x76669635, offset: 0, filename:  }
cpu:  0, pid:    0, tid:    0 { type: mmap, pid: 0, tid: 0, start: 0, length: 0x6422ef6b, offset: 0, filename:  }
cpu:  2, pid: 2255, tid: 2255 { type: mmap, pid: 2255, tid: 2255, start: 0x2, length: 0xe078757a, offset: 0, filename:  }
cpu:  1, pid: 5769, tid: 5769 { type: fork, pid: 30127, ppid: 5769, tid: 30127, ptid: 5769, time: 103893991270534}
cpu:  6, pid: 30127, tid: 30127 { type: comm, pid: 30127, tid: 30127, comm: ls }
cpu:  6, pid: 30127, tid: 30127 { type: exit, pid: 30127, ppid: 30127, tid: 30127, ptid: 30127, time: 103893993273024}

The first 8 mmap events in this 8 way machine are a mistery that is still being
investigated.

More of the tools/perf/util/ APIs will be exposed via this python binding as
the need arises. For now the focus is on creating events and processing them,
symbol resolution is an obvious next step, with tracepoint variables as a close
second step.

Cc: Clark Williams <williams@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>