linux-stable.git/tools/perf/util/sort.c, branch v3.8

perf tools: Remove warnings on JIT samples for srcline sort key

2012-10-16T16:05:38+00:00

When using the srcline sort key with perf report, I see many lines of
warning related to JIT samples like below:

  addr2line: '/tmp/perf-1397.map': No such file

Since it's not a ELF binary and doesn't provide such information, just
use the raw ip address.

Signed-off-by: Namhyung Kim 
Cc: David Ahern 
Cc: Ingo Molnar 
Cc: Irina Tirdea 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1350272383-7016-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix segfault when using srcline sort key

2012-10-16T16:05:07+00:00

The srcline sort key is for grouping samples based on their source file
and line number.  It use addr2line tool to get the information but it
requires dso name.  It caused a segfault when a sample does not have the
name by dereferencing a NULL pointer.  Fix it by using raw ip addresses
for those samples.

Signed-off-by: Namhyung Kim 
Cc: Ingo Molnar 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1350272383-7016-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add sort__has_sym

2012-09-17T16:08:59+00:00

The sort__has_sym variable is for checking whether the sort_list
includes 'symbol' as a sort key.  It will be used for later patch.

Signed-off-by: Namhyung Kim 
Cc: Ingo Molnar 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1347611729-16994-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Use __maybe_used for unused variables

2012-09-11T15:19:15+00:00

perf defines both __used and __unused variables to use for marking
unused variables. The variable __used is defined to
__attribute__((__unused__)), which contradicts the kernel definition to
__attribute__((__used__)) for new gcc versions. On Android, __used is
also defined in system headers and this leads to warnings like: warning:
'__used__' attribute ignored

__unused is not defined in the kernel and is not a standard definition.
If __unused is included everywhere instead of __used, this leads to
conflicts with glibc headers, since glibc has a variables with this name
in its headers.

The best approach is to use __maybe_unused, the definition used in the
kernel for __attribute__((unused)). In this way there is only one
definition in perf sources (instead of 2 definitions that point to the
same thing: __used and __unused) and it works on both Linux and Android.
This patch simply replaces all instances of __used and __unused with
__maybe_unused.

Signed-off-by: Irina Tirdea 
Acked-by: Pekka Enberg 
Cc: David Ahern 
Cc: Ingo Molnar 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Steven Rostedt 
Link: http://lkml.kernel.org/r/1347315303-29906-7-git-send-email-irina.tirdea@intel.com
[ committer note: fixed up conflict with a116e05 in builtin-sched.c ]
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Replace sort's standalone field_sep with symbol_conf.field_sep

2012-09-08T00:50:11+00:00

The repsep_snprintf function was still using standalone field_sep, which
not even set anymore.

Replacing it with 'symbol_conf.field_sep'.

Signed-off-by: Jiri Olsa 
Cc: Andi Kleen 
Cc: Corey Ashford 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Namhyung Kim 
Cc: Paul E. McKenney 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1346946426-13496-3-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add sort by src line/number

2012-06-19T16:06:18+00:00

Using addr2line for now, requires debuginfo, needs more work to support
detached debuginfo, aka foo-debuginfo packages.

Example:

	[root@sandy ~]# perf record -a sleep 3
	[ perf record: Woken up 1 times to write data ]
	[ perf record: Captured and wrote 0.555 MB perf.data (~24236 samples) ]
	[root@sandy ~]# perf report -s dso,srcline 2>&1 | grep -v ^# | head -5
	    22.41%  [kernel.kallsyms]  /home/git/linux/drivers/idle/intel_idle.c:280
	     4.79%  [kernel.kallsyms]  /home/git/linux/drivers/cpuidle/cpuidle.c:148
	     4.78%  [kernel.kallsyms]  /home/git/linux/arch/x86/include/asm/atomic64_64.h:121
	     4.49%  [kernel.kallsyms]  /home/git/linux/kernel/sched/core.c:1690
	     4.30%  [kernel.kallsyms]  /home/git/linux/include/linux/seqlock.h:90
	[root@sandy ~]#

[root@sandy ~]# perf top -U -s dso,symbol,srcline
Samples: 1K of event 'cycles', Event count (approx.): 589617389
 18.66%  [kernel]  [k] copy_user_generic_unrolled   /home/git/linux/arch/x86/lib/copy_user_64.S:143
  7.83%  [kernel]  [k] clear_page                   /home/git/linux/arch/x86/lib/clear_page_64.S:39
  6.59%  [kernel]  [k] clear_page                   /home/git/linux/arch/x86/lib/clear_page_64.S:38
  3.66%  [kernel]  [k] page_fault                   /home/git/linux/arch/x86/kernel/entry_64.S:1379
  3.25%  [kernel]  [k] clear_page                   /home/git/linux/arch/x86/lib/clear_page_64.S:40
  3.12%  [kernel]  [k] clear_page                   /home/git/linux/arch/x86/lib/clear_page_64.S:37
  2.74%  [kernel]  [k] clear_page                   /home/git/linux/arch/x86/lib/clear_page_64.S:36
  2.39%  [kernel]  [k] clear_page                   /home/git/linux/arch/x86/lib/clear_page_64.S:43
  2.12%  [kernel]  [k] ioread32                     /home/git/linux/lib/iomap.c:90
  1.51%  [kernel]  [k] copy_user_generic_unrolled   /home/git/linux/arch/x86/lib/copy_user_64.S:144
  1.19%  [kernel]  [k] copy_user_generic_unrolled   /home/git/linux/arch/x86/lib/copy_user_64.S:154

Suggested-by: Andi Kleen 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Mike Galbraith 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-pdmqbng9twz06jzkbgtuwbp8@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2012-03-20T17:29:15+00:00

Pull perf events changes for v3.4 from Ingo Molnar:

 - New "hardware based branch profiling" feature both on the kernel and
   the tooling side, on CPUs that support it.  (modern x86 Intel CPUs
   with the 'LBR' hardware feature currently.)

   This new feature is basically a sophisticated 'magnifying glass' for
   branch execution - something that is pretty difficult to extract from
   regular, function histogram centric profiles.

   The simplest mode is activated via 'perf record -b', and the result
   looks like this in perf report:

	$ perf record -b any_call,u -e cycles:u branchy

	$ perf report -b --sort=symbol
	    52.34%  [.] main                   [.] f1
	    24.04%  [.] f1                     [.] f3
	    23.60%  [.] f1                     [.] f2
	     0.01%  [k] _IO_new_file_xsputn    [k] _IO_file_overflow
	     0.01%  [k] _IO_vfprintf_internal  [k] _IO_new_file_xsputn
	     0.01%  [k] _IO_vfprintf_internal  [k] strchrnul
	     0.01%  [k] __printf               [k] _IO_vfprintf_internal
	     0.01%  [k] main                   [k] __printf

   This output shows from/to branch columns and shows the highest
   percentage (from,to) jump combinations - i.e.  the most likely taken
   branches in the system.  "branches" can also include function calls
   and any other synchronous and asynchronous transitions of the
   instruction pointer that are not 'next instruction' - such as system
   calls, traps, interrupts, etc.

   This feature comes with (hopefully intuitive) flat ascii and TUI
   support in perf report.

 - Various 'perf annotate' visual improvements for us assembly junkies.
   It will now recognize function calls in the TUI and by hitting enter
   you can follow the call (recursively) and back, amongst other
   improvements.

 - Multiple threads/processes recording support in perf record, perf
   stat, perf top - which is activated via a comma-list of PIDs:

	perf top -p 21483,21485
	perf stat -p 21483,21485 -ddd
	perf record -p 21483,21485

 - Support for per UID views, via the --uid paramter to perf top, perf
   report, etc.  For example 'perf top --uid mingo' will only show the
   tasks that I am running, excluding other users, root, etc.

 - Jump label restructurings and improvements - this includes the
   factoring out of the (hopefully much clearer) include/linux/static_key.h
   generic facility:

	struct static_key key = STATIC_KEY_INIT_FALSE;

	...

	if (static_key_false(&key))
	        do unlikely code
	else
	        do likely code

	...
	static_key_slow_inc();
	...
	static_key_slow_inc();
	...

   The static_key_false() branch will be generated into the code with as
   little impact to the likely code path as possible.  the
   static_key_slow_*() APIs flip the branch via live kernel code patching.

   This facility can now be used more widely within the kernel to
   micro-optimize hot branches whose likelihood matches the static-key
   usage and fast/slow cost patterns.

 - SW function tracer improvements: perf support and filtering support.

 - Various hardenings of the perf.data ABI, to make older perf.data's
   smoother on newer tool versions, to make new features integrate more
   smoothly, to support cross-endian recording/analyzing workflows
   better, etc.

 - Restructuring of the kprobes code, the splitting out of 'optprobes',
   and a corner case bugfix.

 - Allow the tracing of kernel console output (printk).

 - Improvements/fixes to user-space RDPMC support, allowing user-space
   self-profiling code to extract PMU counts without performing any
   system calls, while playing nice with the kernel side.

 - 'perf bench' improvements

 - ... and lots of internal restructurings, cleanups and fixes that made
   these features possible.  And, as usual this list is incomplete as
   there were also lots of other improvements

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (120 commits)
  perf report: Fix annotate double quit issue in branch view mode
  perf report: Remove duplicate annotate choice in branch view mode
  perf/x86: Prettify pmu config literals
  perf report: Enable TUI in branch view mode
  perf report: Auto-detect branch stack sampling mode
  perf record: Add HEADER_BRANCH_STACK tag
  perf record: Provide default branch stack sampling mode option
  perf tools: Make perf able to read files from older ABIs
  perf tools: Fix ABI compatibility bug in print_event_desc()
  perf tools: Enable reading of perf.data files from different ABI rev
  perf: Add ABI reference sizes
  perf report: Add support for taken branch sampling
  perf record: Add support for sampling taken branch
  perf tools: Add code to support PERF_SAMPLE_BRANCH_STACK
  x86/kprobes: Split out optprobe related code to kprobes-opt.c
  x86/kprobes: Fix a bug which can modify kernel code permanently
  x86/kprobes: Fix instruction recovery on optimized path
  perf: Add callback to flush branch_stack on context switch
  perf: Disable PERF_SAMPLE_BRANCH_* when not supported
  perf/x86: Add LBR software filter support for Intel CPUs
  ...

perf tools: Incorrect use of snprintf results in SEGV

2012-03-14T15:36:19+00:00

I have a workload where perf top scribbles over the stack and we SEGV.
What makes it interesting is that an snprintf is causing this.

The workload is a c++ gem that has method names over 3000 characters
long, but snprintf is designed to avoid overrunning buffers. So what
went wrong?

The problem is we assume snprintf returns the number of characters
written:

    ret += repsep_snprintf(bf + ret, size - ret, "[%c] ", self->level);
...
    ret += repsep_snprintf(bf + ret, size - ret, "%s", self->ms.sym->name);

Unfortunately this is not how snprintf works. snprintf returns the
number of characters that would have been written if there was enough
space. In the above case, if the first snprintf returns a value larger
than size, we pass a negative size into the second snprintf and happily
scribble over the stack. If you have 3000 character c++ methods thats a
lot of stack to trample.

This patch fixes repsep_snprintf by clamping the value at size - 1 which
is the maximum snprintf can write before adding the NULL terminator.

I get the sinking feeling that there are a lot of other uses of snprintf
that have this same bug, we should audit them all.

Cc: David Ahern 
Cc: Eric B Munson 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Yanmin Zhang 
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/20120307114249.44275ca3@kryten
Signed-off-by: Anton Blanchard 
Signed-off-by: Arnaldo Carvalho de Melo

perf report: Auto-detect branch stack sampling mode

2012-03-09T07:26:08+00:00

This patch enhances perf report to auto-detect when the
perf.data file contains samples with branch stacks. That way it
is not necessary to use the -b option.

To force branch view mode to off, simply use --no-branch-stack.

Signed-off-by: Stephane Eranian 
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: asharma@fb.com
Cc: ravitillo@lbl.gov
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1331246868-19905-4-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar

perf tools: Add code to support PERF_SAMPLE_BRANCH_STACK

2012-03-09T07:26:04+00:00

This patch adds:

 - ability to parse samples with PERF_SAMPLE_BRANCH_STACK
 - sort on branches (dso_from, symbol_from, dso_to, symbol_to, mispredict)
 - build histograms on branches

Signed-off-by: Roberto Agostino Vitillo 
Signed-off-by: Stephane Eranian 
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: robert.richter@amd.com
Cc: ming.m.lin@intel.com
Cc: andi@firstfloor.org
Cc: asharma@fb.com
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1328826068-11713-12-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar