Currently symbol resolution does not work for 64-bit programs on architectures
that use function descriptors such as ppc64.

The problem is that a symbol doesn't point to a text address, it points to a
data area that contains (amongst other things) a pointer to the text address.

We look for a section called ".opd" which is the function descriptor area. To
create the full symbol table, when we see a symbol in the function descriptor
section we load the first pointer and use that as the text address.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1276523793-15422-1-git-send-email-ebmunson@us.ibm.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Eric B Munson <ebmunson@us.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

A bug was introduced by commit c45c6ea2.

Perf record was scanning /proc/PID to create synthetic PERF_RECOR_MMAP
entries even though it was running in per-thread mode. There was a bogus
check to select what mmaps to synthesize. We only need all processes in
system-wide mode.

Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <4c192107.4f1ee30a.4316.fffff98e@mx.google.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Moving the tests to a separate file, feature-tests.mak and using a try-cc
function similar to the try-run in Kbuild.

This also makes the output more quiet as we can stop using the INTERMEDIATE
target to remove the .perf.dev.null file needed for some gcc versions where
/dev/null can't be used as the output file name.

As the tests get shorter by uninlining the source code used to test for
features, we can more properly use identation.

The feature tests itself can be made more clear and reused, like when trying to
see what is needed to have bfd_demangle.

We also get a bit closer to reusing scripts/Kbuild.include, reducing the
distance from the kernel build system.

Tests performed:

[root@emilia perf]# make -j9 O=/tmp/perf
PERF_VERSION = 0.0.2.PERF
    GEN /tmp/perf/common-cmds.h
    * new build flags or prefix
    GEN perf-archive
    CC /tmp/perf/builtin-annotate.o
    CC /tmp/perf/bench/sched-messaging.o
    CC /tmp/perf/builtin-diff.o
<SNIP>
    CC /tmp/perf/scripts/python/Perf-Trace-Util/Context.o
    CC /tmp/perf/perf.o
    CC /tmp/perf/builtin-help.o
    AR /tmp/perf/libperf.a
    LINK /tmp/perf/perf
[root@emilia perf]#

If we uninstall, for instance newt-devel we get:

[root@emilia perf]# rpm -e newt-devel
[root@emilia perf]# make -j9 O=/tmp/perf
Makefile:564: newt not found, disables TUI support. Please install newt-devel or libnewt-dev
    * new build flags or prefix
    GEN perf-archive
    CC /tmp/perf/perf.o
    CC /tmp/perf/builtin-annotate.o
<SNIP>
    AR /tmp/perf/libperf.a
    LINK /tmp/perf/perf
[root@emilia perf]#

And then binutils-devel:

[root@emilia perf]# make -j9 O=/tmp/perf
Makefile:564: newt not found, disables TUI support. Please install newt-devel or libnewt-dev
Makefile:632: No bfd.h/libbfd found, install binutils-dev[el]/zlib-static to gain symbol demangling
    * new build flags or prefix
    GEN perf-archive
    CC /tmp/perf/perf.o
<SNIP>
    AR /tmp/perf/libperf.a
    LINK /tmp/perf/perf
[root@emilia perf]#

And then strictly required devel packages:

[root@emilia perf]# rpm -e elfutils-libelf-devel elfutils-devel
[root@emilia perf]# make -j9 O=/tmp/perf
Makefile:509: No libdw.h found or old libdw.h found or elfutils is older than 0.138, disables dwarf support. Please install new elfutils-devel/libdw-dev
Makefile:542: *** No libelf.h/libelf found, please install libelf-dev/elfutils-libelf-devel.  Stop.
[root@emilia perf]#

After installing everything back on:

[root@emilia perf]# yum install elfutils-devel binutils-devel newt-devel
<SNIP>
Installed:
  binutils-devel.x86_64 0:2.20.51.0.2-5.11.el6
  elfutils-devel.x86_64 0:0.147-1.el6
  elfutils-libelf-devel.x86_64 0:0.147-1.el6
  newt-devel.x86_64 0:0.52.11-1.el6

Complete!
[root@emilia perf]# make -j9
PERF_VERSION = 0.0.2.PERF
    GEN common-cmds.h
    * new build flags or prefix
    GEN perf-archive
    CC builtin-annotate.o
<SNIP>
    AR libperf.a
    LINK perf
[root@emilia perf]# make -j9
[root@emilia perf]#

Thanks to Sam for pointing me to try-run.

Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into perf/core

Cleanup. Factor the common code in save_stack_address() and
save_stack_address_nosched().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20100603193243.GA31534@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

If CONFIG_FRAME_POINTER=n, print_context_stack() shouldn't neglect the
non-reliable addresses on stack, this is all we have if dump_trace(bp)
is called with the wrong or zero bp.

For example, /proc/pid/stack doesn't work if CONFIG_FRAME_POINTER=n.

This patch obviously has no effect if CONFIG_FRAME_POINTER=y, otherwise
it reverts 1650743c "x86: don't save unreliable stack trace entries".

Also, remove the unnecessary type-cast.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <20100603193239.GA31530@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

We have been resisting new ftrace plugins and removing existing
ones, and kmemtrace has been superseded by kmem trace events
and perf-kmem, so we remove it.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
[ remove kmemtrace from the makefile, handle slob too ]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

The local64.h include dependency was not dependent on PERF_EVENT=y,
which meant that arch's without atomic64_t support ended up including
it and failed to build.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>

Since now all modification to event->count (and ->prev_count
and ->period_left) are local to a cpu, change then to local64_t so we
avoid the LOCK'ed ops.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Only child counters adding back their values into the parent counter
are responsible for cross-cpu updates to event->count.

So if we pull that out into a new child_count variable, we get an
event->count that is only modified locally.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Create a helper function for those sites that want to read the event count.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

On 64bit, local_t is of size long, and thus we make local64_t an alias.
On 32bit, we fall back to atomic64_t. (architecture can provide optimized
32-bit version)

(This new facility is to be used by perf events optimizations.)
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linux-arch@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Currently there are perf_buffer_alloc() + perf_buffer_init() + some
separate bits, fold it all into a single perf_buffer_alloc() and only
leave the attachment to the event separate.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Rename to clarify code.

s/perf_mmap_data/perf_buffer/g and selective s/data/buffer/g
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

On Netburst PMU we need a second write to a performance counter
due to cpu erratum.

A simple flag test instead of alternative instructions was choosen
because wrmsrl is already a macro and if virtualization is turned
on will need an additional wrapper call which is more expencise.

nb: we should propably switch to jump-labels as only this facility
reach the mainline.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Lin Ming <ming.m.lin@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100602212304.GC5264@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Clarify some of the transactional group scheduling API details
and change it so that a successfull ->commit_txn also closes
the transaction.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1274803086.5882.1752.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Add the capacility to track data mmap()s. This can be used together
with PERF_SAMPLE_ADDR for data profiling.
Signed-off-by: Anton Blanchard <anton@samba.org>
[Updated code for stable perf ABI]
Signed-off-by: Eric B Munson <ebmunson@us.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1274193049-25997-1-git-send-email-ebmunson@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

__DO_TRACE() already calls the callbacks under rcu_read_lock_sched(),
which is sufficient for our needs, avoid doing it again.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Inline perf_swevent_put_recursion_context into perf_tp_event(), this
shrinks the per trace template code footprint and saves a function
call.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

The boot tracer is useless. It simply logs the initcalls
but in fact these initcalls are also logged through printk
while using the initcall_debug kernel parameter.

Nobody seem to be using it so far. Then just remove it.
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Chase Douglas <chase.douglas@canonical.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <20100526105753.GA5677@cr0.nay.redhat.com>
[ remove the hooks in main.c, and the headers ]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

Drop this argument now that we always want to rewind only to the
state of the first caller.
It means frame pointers are not necessary anymore to reliably get
the source of an event. But this also means we need this helper
to be a macro now, as an inline function is not an option since
we need to know when to provide a default implentation.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: David Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>

arch/x86/include/asm/stacktrace.h and arch/x86/kernel/dumpstack.h
declare headers of objects that deal with the same topic.
Actually most of the files that include stacktrace.h also include
dumpstack.h

Although dumpstack.h seems more reserved for internals of stack
traces, those are quite often needed to define specialized stack
trace operations. And perf event arch headers are going to need
access to such low level operations anyway. So don't continue to
bother with dumpstack.h as it's not anymore about isolated deep
internals.

v2: fix struct stack_frame definition conflict in sysprof
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Soeren Sandmann <sandmann@daimi.au.dk>

Fixes to 'cpuid10_edx' to comply with Intel documentation.
According to the Intel Manual, Volume 2A, Table 3-12, the cpuid for
architecture performance monitoring returns, in EDX, two pieces of
information:

  1) Number of fixed-function counters (5 bits, not 4)
  2) Width of fixed-function counters (8 bits)
Signed-off-by: Livio Soares <livio@eecg.toronto.edu>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux-2.6 into perf/core

Merge branch 'tip/perf/core-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core

Merge branch 'for-tip' of git://git.kernel.org/pub/scm/linux/kernel/git/rric/oprofile into perf/urgent

Frederic reported that frequency driven swevents didn't work properly
and even caused a division-by-zero error.

It turns out there are two bugs, the division-by-zero comes from a
failure to deal with that in perf_calculate_period().

The other was more interesting and turned out to be a wrong comparison
in perf_adjust_period(). The comparison was between an s64 and u64 and
got implicitly converted to an unsigned comparison. The problem is
that period_left is typically < 0, so it ended up being always true.

Cure this by making the local period variables s64.
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

So that we don't require that the kernel be configured first, and as we
don't use KERNELRELEASE at all in the -src-pkg targets, we need o add a
new wildcard for targets ending in src-pkg:

On a make mrproper'ed kernel we get this without this patch:

[linux-2.6-tip]$ LANG= make perf-tarbz2-src-pkg
/bin/sh: include/config/kernel.release: No such file or directory
make: *** [include/config/kernel.release] Error 1
[acme@emilia linux-2.6-tip]$
Acked-by: Michal Marek <mmarek@suse.cz>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <20100604173552.GA875@ghostprotocols.net>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Fix potential initial_lfsr buffer overrun.
Writing past the end of the buffer could happen when index == ENTRIES
Signed-off-by: Denis Kirjanov <dkirjanov@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Robert Richter <robert.richter@amd.com>

In a shared multi-core environment, users want to analyze why their
program was slow. In particular, if the code ran slower only on certain
CPUs due to interference from other programs or kernel threads, the user
should be able to notice that.

Sample usage:

perf record -f -a -- sleep 3
perf report --sort cpu,comm

Workload:

program is running on 16 CPUs
Experiencing interference from an antagonist only on 4 CPUs.

  Samples: 106218177676 cycles

  Overhead  CPU          Command
  ........  ...  ...............

     6.25%  2            program
     6.24%  6            program
     6.24%  11           program
     6.24%  5            program
     6.24%  9            program
     6.24%  10           program
     6.23%  15           program
     6.23%  7            program
     6.23%  3            program
     6.23%  14           program
     6.22%  1            program
     6.20%  13           program
     3.17%  12           program
     3.15%  8            program
     3.14%  0            program
     3.13%  4            program
     3.11%  4         antagonist
     3.11%  0         antagonist
     3.10%  8         antagonist
     3.07%  12        antagonist

Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <20100505181612.GA5091@sharma-home.net>
Signed-off-by: Arun Sharma <aruns@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Simplifying the tools that were using both in sequence and allowing
upcoming simplifications, such as Arun's patch to sort by cpus.

Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric 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: Arnaldo Carvalho de Melo <acme@redhat.com>

Perf report is demangling symbols but not annotate.

The former uses internal demangling via libbdf or libiberty. The latter
executes objdump which by default does not demangle symbols.

This patch adds the -C option to the objdump cmdline to enable symbol
demangling.

Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <4c07b323.2126e30a.6245.0e1e@mx.google.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

This patch adds the ability to specify an alternate directory to store the
buildid cache (buildids, copy of binaries). By default, it is hardcoded to
$HOME/.debug. This directory contains immutable data. The layout of the
directory is such that no conflicts in filenames are possible. A modification
in a file, yields a different buildid and thus a different location in the
subdir hierarchy.

You may want to put the buildid cache elsewhere because of disk space
limitation or simply to share the cache between users. It is also useful for
remote collect vs. local analysis of profiles.

This patch adds a new config option to the perfconfig file.  Under the tag
'buildid', there is a dir option. For instance, if you have:

$ cat /etc/perfconfig
[buildid]
dir = /var/cache/perf-buildid

All buildids and binaries are be saved in the directory specified. The perf
record, buildid-list, buildid-cache, report, annotate, and archive commands
will it to pull information out.

The option can be set in the system-wide perfconfig file or in the
$HOME/.perfconfig file.

Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
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: <4c055fb7.df0ce30a.5f0d.ffffae52@mx.google.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Useful for when people want to try some version of the perf tools and don't
wants to download the kernel tarball.

Here is a session using this new target:

  [root@emilia linux-2.6-tip]# make help | grep -i perf
    perf-tar-src-pkg    - Build perf-2.6.35-rc1.tar source tarball
    perf-targz-src-pkg  - Build perf-2.6.35-rc1.tar.gz source tarball
    perf-tarbz2-src-pkg - Build perf-2.6.35-rc1.tar.bz2 source tarball
  [root@emilia linux-2.6-tip]# make perf-tarbz2-src-pkg
    TAR
  [root@emilia linux-2.6-tip]# ls -la perf-2.6.35-rc1.tar.bz2
  -rw-r--r-- 1 root root 295731 May 31 11:18 perf-2.6.35-rc1.tar.bz2
  [root@emilia linux-2.6-tip]# tar xf perf-2.6.35-rc1.tar.bz2
  [root@emilia linux-2.6-tip]# cd perf-2.6.35-rc1
  [root@emilia perf-2.6.35-rc1]# ls
  arch  HEAD  include  lib  tools
  [root@emilia perf-2.6.35-rc1]# cd tools/perf
  [root@emilia perf]# make -j9 2>&1 | tail
      CC arch/x86/util/dwarf-regs.o
      CC util/probe-finder.o
      CC util/newt.o
      CC util/scripting-engines/trace-event-perl.o
      CC scripts/perl/Perf-Trace-Util/Context.o
      CC perf.o
      CC builtin-help.o
      AR libperf.a
      LINK perf
  rm .perf.dev.null
  [root@emilia perf]# ./perf record -a sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.262 MB perf.data (~11457 samples) ]
  [root@emilia perf]# ./perf report | head -12
  # Events: 6K cycles
  #
  # Overhead          Command       Shared Object  Symbol
  # ........  ...............  ..................  ......
  #
       4.73%             perf  [kernel.kallsyms]   [k] format_decode
       4.49%             perf  libc-2.12.so        [.] _IO_file_underflow_internal
       4.38%             init  [kernel.kallsyms]   [k] mwait_idle
       3.29%             perf  [kernel.kallsyms]   [k] vsnprintf
       2.38%             init  [kernel.kallsyms]   [k] sched_clock_local
       2.35%             init  [kernel.kallsyms]   [k] apic_timer_interrupt
       1.86%     sirq-timer/5  [kernel.kallsyms]   [k] find_busiest_group
  [root@emilia perf]#
Acked-by: Michal Marek <mmarek@suse.cz>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <20100528185357.GA28009@ghostprotocols.net>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

This patch adds a -C option to stat, record, top to designate a list of CPUs to
monitor. CPUs can be specified as a comma-separated list or ranges, no space
allowed.

Examples:
$ perf record -a -C0-1,4-7 sleep 1
$ perf top -C0-4
$ perf stat -a -C1,2,3,4 sleep 1

With perf record in per-thread mode with inherit mode on, samples are collected
only when the thread runs on the designated CPUs.

The -C option does not turn on system-wide mode automatically.

Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric 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: <4bff9496.d345d80a.41fe.7b00@mx.google.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

It is useful to know on which CPU a sample was captured on.
The information is captured with perf record -R but it was
not printed out by perf report -D. This patch adds this.

When -R is not used, cpu is set to -1to indicate that
the CPU is unknown (it is not captured).

Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <4bff964c.e88cd80a.3106.7d31@mx.google.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Merge branch 'perf/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux-2.6 into perf/urgent

We need to set the long name to the name specified via, for instance,
'perf annotate --vmlinux /path/to/vmlinux', if not it will remain as
'[kernel.kallsyms]' and that will make annotate fail when passing this
as the vmlinux name in the call to objdump.

The way this is setup grew unwieldly and dso__load_vmlinux is the
function that should allocate space for the long name, with callers not
assuming that filenames should be allocated somehow by then (strdup,
dso__build_id_filename, etc).

For now this is the minimalistic patch, a proper fix for .36 will be
made.
Reported-by: Stephane Eranian <eranian@google.com>
Tested-by: Stephane Eranian <eranian@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric 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: <20100604003900.GD10469@ghostprotocols.net>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The ftrace_preempt_disable/enable functions were to address a
recursive race caused by the function tracer. The function tracer
traces all functions which makes it easily susceptible to recursion.
One area was preempt_enable(). This would call the scheduler and
the schedulre would call the function tracer and loop.
(So was it thought).

The ftrace_preempt_disable/enable was made to protect against recursion
inside the scheduler by storing the NEED_RESCHED flag. If it was
set before the ftrace_preempt_disable() it would not call schedule
on ftrace_preempt_enable(), thinking that if it was set before then
it would have already scheduled unless it was already in the scheduler.

This worked fine except in the case of SMP, where another task would set
the NEED_RESCHED flag for a task on another CPU, and then kick off an
IPI to trigger it. This could cause the NEED_RESCHED to be saved at
ftrace_preempt_disable() but the IPI to arrive in the the preempt
disabled section. The ftrace_preempt_enable() would not call the scheduler
because the flag was already set before entring the section.

This bug would cause a missed preemption check and cause lower latencies.

Investigating further, I found that the recusion caused by the function
tracer was not due to schedule(), but due to preempt_schedule(). Now
that preempt_schedule is completely annotated with notrace, the recusion
no longer is an issue.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

The function tracer code uses ftrace_preempt_disable() to disable
preemption instead of normal preempt_disable(). But there's a slight
race condition that may cause it to lose a preemption check.

This was made to keep the function tracer from recursing on itself
by disabling preemption then having the enable call the function tracer
again, causing infinite recursion.

The bug was assumed to happen if the call was just in schedule, but
this is incorrect. The bug is caused by preempt_schedule() which
is called by preempt_enable(). The calling of preempt_enable() when
NEED_RESCHED was set would call preempt_schedule() which would call
the function tracer again.

By making the preempt_schedule() and add_preempt_count() notrace
then this will prevent the inifinite recursion. This is because
the add_preempt_count() would stop the preempt_enable() in the
function tracer from calling preempt_schedule() again.

The sub_preempt_count() is also made notrace just to keep it
symmetric.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>