While implementing event__preprocess_sample, that will do all of
the symbol lookup in one convenient function, I noticed that
util/process_event.[ch] were not being used at all, then started
looking if there were other functions that could be shared
and...

All those functions really don't need to receive offset + head,
the only thing they did was common to all of them, so do it at
one place instead.

Stats about number of each type of event processed now is done
in a central place.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1259346563-12568-11-git-send-email-acme@infradead.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

And also express its configuration toggles via a struct.

Now all one has to do is to call symbol__init(NULL) if the
defaults are OK, or pass a struct symbol_conf pointer with the
desired configuration.

If a tool uses kernel_maps__find_symbol() to look at the kernel
and modules mappings for a symbol but didn't call symbol__init()
first, that will generate a one time warning too, alerting the
subcommand developer that symbol__init() must be called.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1259071517-3242-2-git-send-email-acme@infradead.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Now that we can check the buildid to see if it really matches,
this can be done safely:

  vmlinux
  /boot/vmlinux
  /boot/vmlinux-<uts.release>
  /lib/modules/<uts.release>/build/vmlinux
  /usr/lib/debug/lib/modules/%s/vmlinux

More can be added - if you know about distros that put the
vmlinux somewhere else please let us know.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1259001550-8194-1-git-send-email-acme@infradead.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Just like we do with the other DSOs. This also simplifies the
kernel_maps setup process, now all that the tools need to do is
to call kernel_maps__init and the maps for the modules and
kernel will be created, then, later, when
kernel_maps__find_symbol() is used, it will also call
maps__find_symbol that already checks if the symtab was loaded,
loading it if needed.

Now if one does 'perf top --hide_kernel_symbols' we won't pay
the price of loading the (many) symbols in /proc/kallsyms or
vmlinux.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1258757489-5978-4-git-send-email-acme@infradead.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

It should just load kernel symbols, not load the list of
modules. There are more stuff to move to other routines, but
lets do it in several steps.

End goal is to be able to defer symbol table loading till we
find a hit for that map address range. So that the kernel &
modules are handled just like all the other DSOs in the system.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1258757489-5978-1-git-send-email-acme@infradead.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Propagate the error, that, interestingly, are already handled by
all callers :-)
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1258649757-17554-3-git-send-email-acme@infradead.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

And also don't call the constructor in it, this way it adheres
to the model the other methods follow.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1258649757-17554-1-git-send-email-acme@infradead.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.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>
LKML-Reference: <1258396365-29217-1-git-send-email-acme@infradead.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Build a set of section headers for features right after the
datas. Each implemented feature will have one of such section
header that provides the offset and the size of the data
manipulated by the feature.

The trace informations have moved after the data and are
recorded on exit time.

The new layout is as follows:

 -----------------------
                             ___
 [ magic               ]      |
 [ header size         ]      |
 [ attr size           ]      |
 [ attr content offset ]      |
 [ attr content size   ]      |
 [ data offset         ]  File Headers
 [ data size           ]      |
 [ event_types offset  ]      |
 [ event_types size    ]      |
 [ feature bitmap      ]      v

 [ attr section        ]
 [ events section      ]

                             ___
 [         X           ]      |
 [         X           ]      |
 [         X           ]    Datas
 [         X           ]      |
 [         X           ]      v

                             ___
 [ Feature 1 offset    ]      |
 [ Feature 1 size      ] Features headers
 [ Feature 2 offset    ]      |
 [ Feature 2 size      ]      v

 [ Feature 1 content   ]
 [ Feature 2 content   ]
 -----------------------

We have as many feature's section headers as we have features in
use for the current file.

Say Feat 1 and Feat 3 are used by the file, but not Feat 2. Then
the feature headers will be like follows:

[ Feature 1 offset    ]      |
[ Feature 1 size      ] Features headers
[ Feature 3 offset    ]      |
[ Feature 3 size      ]      v

There is no hole to cover Feature 2 that is not in use here. We
only need to cover the needed headers in order, from the lowest
feature bit to the highest.

Currently we have two features: HEADER_TRACE_INFO and
HEADER_BUILD_ID. Both have their contents that follow the
feature headers. Putting the contents right after the feature
headers is not mandatory though. While we keep the feature
headers right after the data and in order, their offsets can
point everywhere. We have just put the two above feature
contents in the end of the file for convenience.

The purpose of this layout change is to have a file format that
scales while keeping it simple: having such linear feature
headers is less error prone wrt forward/backward compatibility
as the content of a feature can be put anywhere, its location
can even change by the time, it's fine because its headers will
tell where it is. And we know how to find these headers,
following the above rules.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
LKML-Reference: <1257911467-28276-6-git-send-email-fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Keep the build-ids reading implementation in the data mapping
but move its call to the headers so that we have a better
control on it (offset seeking, size passing, etc..).
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
LKML-Reference: <1257911467-28276-4-git-send-email-fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

With this change 'perf record' will intercept PERF_RECORD_MMAP
calls, creating a linked list of DSOs, then when the session
finishes, it will traverse this list and read the buildids,
stashing them at the end of the file and will set up a new
feature bit in the header bitmask.

'perf report' will then notice this feature and populate the
'dsos' list and set the build ids.

When reading the symtabs it will refuse to load from a file that
doesn't have the same build id. This improves the
reliability of the profiler output, as symbols and profiling
data is more guaranteed to match.

Example:

 [root@doppio ~]# perf report | head
 /home/acme/bin/perf with build id b1ea544ac3746e7538972548a09aadecc5753868 not found, continuing without symbols
  # Samples: 2621434559
  #
  # Overhead          Command                  Shared Object  Symbol
  # ........  ...............  .............................  ......
  #
       7.91%             init  [kernel]        [k] read_hpet
       7.64%             init  [kernel]        [k] mwait_idle_with_hints
       7.60%          swapper  [kernel]        [k] read_hpet
       7.60%          swapper  [kernel]        [k] mwait_idle_with_hints
       3.65%             init  [kernel]        [k] 0xffffffffa02339d9
[root@doppio ~]#

In this case the 'perf' binary was an older one, vanished,
so its symbols probably wouldn't match or would cause subtly
different (and misleading) output.

Next patches will support the kernel as well, reading the build
id notes for it and the modules from /sys.

Another patch should also introduce a new plumbing command:

'perf list-buildids'

that will then be used in porcelain that is distro specific to
fetch -debuginfo packages where such buildids are present. This
will in turn allow for one to run 'perf record' in one machine
and 'perf report' in another.

Future work on having the buildid sent directly from the kernel
in the PERF_RECORD_MMAP event is needed to close races, as the
DSO can be changed during a 'perf record' session, but this
patch at least helps with non-corner cases and current/older
kernels.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: K. Prasad <prasad@linux.vnet.ibm.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1257367843-26224-1-git-send-email-acme@infradead.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Before we were storing this in the DSO, but in fact this is a
property of the 'symbol' class, not something that will vary
among DSOs, so move it to a global variable and initialize it
using the existing symbol__init routine.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <1256927305-4628-2-git-send-email-acme@infradead.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We have this sym_priv_size mechanism for attaching private areas
to struct symbol entries but annotate wasn't using it, adding
private areas to struct symbol in addition to a ->priv pointer.

Scrap all that and use the sym_priv_size mechanism.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <1256055940-19511-1-git-send-email-acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This librarizes the perf.data file mapping and handling in various
perf tools, roughly reducing the amount of code and fixing the
places that mmap from beginning of the file whereas we want to mmap
from the beginning of the data, leading to page fault because the
mmap window is too small since the trace info are written in the
file too.

TODO:

 - convert perf timechart too
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arjan van de Ven <arjan@infradead.org>
LKML-Reference: <20091007104729.GD5043@nowhere>
Signed-off-by: NIngo Molnar <mingo@elte.hu>