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

Pull perf changes from Ingo Molnar:
 "There are lots of improvements, the biggest changes are:

  Main kernel side changes:

   - Improve uprobes performance by adding 'pre-filtering' support, by
     Oleg Nesterov.

   - Make some POWER7 events available in sysfs, equivalent to what was
     done on x86, from Sukadev Bhattiprolu.

   - tracing updates by Steve Rostedt - mostly misc fixes and smaller
     improvements.

   - Use perf/event tracing to report PCI Express advanced errors, by
     Tony Luck.

   - Enable northbridge performance counters on AMD family 15h, by Jacob
     Shin.

   - This tracing commit:

        tracing: Remove the extra 4 bytes of padding in events

     changes the ABI.  All involved parties (PowerTop in particular)
     seem to agree that it's safe to do now with the introduction of
     libtraceevent, but the devil is in the details ...

  Main tooling side changes:

   - Add 'event group view', from Namyung Kim:

     To use it, 'perf record' should group events when recording.  And
     then perf report parses the saved group relation from file header
     and prints them together if --group option is provided.  You can
     use the 'perf evlist' command to see event group information:

        $ perf record -e '{ref-cycles,cycles}' noploop 1
        [ perf record: Woken up 2 times to write data ]
        [ perf record: Captured and wrote 0.385 MB perf.data (~16807 samples) ]

        $ perf evlist --group
        {ref-cycles,cycles}

     With this example, default perf report will show you each event
     separately.

     You can use --group option to enable event group view:

        $ perf report --group
        ...
        # group: {ref-cycles,cycles}
        # ========
        # Samples: 7K of event 'anon group { ref-cycles, cycles }'
        # Event count (approx.): 6876107743
        #
        #         Overhead  Command      Shared Object                      Symbol
        # ................  .......  .................  ..........................
            99.84%  99.76%  noploop  noploop            [.] main
             0.07%   0.00%  noploop  ld-2.15.so         [.] strcmp
             0.03%   0.00%  noploop  [kernel.kallsyms]  [k] timerqueue_del
             0.03%   0.03%  noploop  [kernel.kallsyms]  [k] sched_clock_cpu
             0.02%   0.00%  noploop  [kernel.kallsyms]  [k] account_user_time
             0.01%   0.00%  noploop  [kernel.kallsyms]  [k] __alloc_pages_nodemask
             0.00%   0.00%  noploop  [kernel.kallsyms]  [k] native_write_msr_safe
             0.00%   0.11%  noploop  [kernel.kallsyms]  [k] _raw_spin_lock
             0.00%   0.06%  noploop  [kernel.kallsyms]  [k] find_get_page
             0.00%   0.02%  noploop  [kernel.kallsyms]  [k] rcu_check_callbacks
             0.00%   0.02%  noploop  [kernel.kallsyms]  [k] __current_kernel_time

     As you can see the Overhead column now contains both of ref-cycles
     and cycles and header line shows group information also - 'anon
     group { ref-cycles, cycles }'.  The output is sorted by period of
     group leader first.

   - Initial GTK+ annotate browser, from Namhyung Kim.

   - Add option for runtime switching perf data file in perf report,
     just press 's' and a menu with the valid files found in the current
     directory will be presented, from Feng Tang.

   - Add support to display whole group data for raw columns, from Jiri
     Olsa.

   - Add per processor socket count aggregation in perf stat, from
     Stephane Eranian.

   - Add interval printing in 'perf stat', from Stephane Eranian.

   - 'perf test' improvements

   - Add support for wildcards in tracepoint system name, from Jiri
     Olsa.

   - Add anonymous huge page recognition, from Joshua Zhu.

   - perf build-id cache now can show DSOs present in a perf.data file
     that are not in the cache, to integrate with build-id servers being
     put in place by organizations such as Fedora.

   - perf top now shares more of the evsel config/creation routines with
     'record', paving the way for further integration like 'top'
     snapshots, etc.

   - perf top now supports DWARF callchains.

   - Fix mmap limitations on 32-bit, fix from David Miller.

   - 'perf bench numa mem' NUMA performance measurement suite

   - ... and lots of fixes, performance improvements, cleanups and other
     improvements I failed to list - see the shortlog and git log for
     details."

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (270 commits)
  perf/x86/amd: Enable northbridge performance counters on AMD family 15h
  perf/hwbp: Fix cleanup in case of kzalloc failure
  perf tools: Fix build with bison 2.3 and older.
  perf tools: Limit unwind support to x86 archs
  perf annotate: Make it to be able to skip unannotatable symbols
  perf gtk/annotate: Fail early if it can't annotate
  perf gtk/annotate: Show source lines with gray color
  perf gtk/annotate: Support multiple event annotation
  perf ui/gtk: Implement basic GTK2 annotation browser
  perf annotate: Fix warning message on a missing vmlinux
  perf buildid-cache: Add --update option
  uprobes/perf: Avoid uprobe_apply() whenever possible
  uprobes/perf: Teach trace_uprobe/perf code to use UPROBE_HANDLER_REMOVE
  uprobes/perf: Teach trace_uprobe/perf code to pre-filter
  uprobes/perf: Teach trace_uprobe/perf code to track the active perf_event's
  uprobes: Introduce uprobe_apply()
  perf: Introduce hw_perf_event->tp_target and ->tp_list
  uprobes/perf: Always increment trace_uprobe->nhit
  uprobes/tracing: Kill uprobe_trace_consumer, embed uprobe_consumer into trace_uprobe
  uprobes/tracing: Introduce is_trace_uprobe_enabled()
  ...

1 files changed, 83 insertions, 0 deletions

diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index 6f51fed45f2d..53d6a3c51d87 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -1842,6 +1842,89 @@ an error.
  # cat buffer_size_kb
 85
 
+Snapshot
+--------
+CONFIG_TRACER_SNAPSHOT makes a generic snapshot feature
+available to all non latency tracers. (Latency tracers which
+record max latency, such as "irqsoff" or "wakeup", can't use
+this feature, since those are already using the snapshot
+mechanism internally.)
+
+Snapshot preserves a current trace buffer at a particular point
+in time without stopping tracing. Ftrace swaps the current
+buffer with a spare buffer, and tracing continues in the new
+current (=previous spare) buffer.
+
+The following debugfs files in "tracing" are related to this
+feature:
+
+  snapshot:
+
+	This is used to take a snapshot and to read the output
+	of the snapshot. Echo 1 into this file to allocate a
+	spare buffer and to take a snapshot (swap), then read
+	the snapshot from this file in the same format as
+	"trace" (described above in the section "The File
+	System"). Both reads snapshot and tracing are executable
+	in parallel. When the spare buffer is allocated, echoing
+	0 frees it, and echoing else (positive) values clear the
+	snapshot contents.
+	More details are shown in the table below.
+
+	status\input  |     0      |     1      |    else    |
+	--------------+------------+------------+------------+
+	not allocated |(do nothing)| alloc+swap |   EINVAL   |
+	--------------+------------+------------+------------+
+	allocated     |    free    |    swap    |   clear    |
+	--------------+------------+------------+------------+
+
+Here is an example of using the snapshot feature.
+
+ # echo 1 > events/sched/enable
+ # echo 1 > snapshot
+ # cat snapshot
+# tracer: nop
+#
+# entries-in-buffer/entries-written: 71/71   #P:8
+#
+#                              _-----=> irqs-off
+#                             / _----=> need-resched
+#                            | / _---=> hardirq/softirq
+#                            || / _--=> preempt-depth
+#                            ||| /     delay
+#           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
+#              | |       |   ||||       |         |
+          <idle>-0     [005] d...  2440.603828: sched_switch: prev_comm=swapper/5 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=snapshot-test-2 next_pid=2242 next_prio=120
+           sleep-2242  [005] d...  2440.603846: sched_switch: prev_comm=snapshot-test-2 prev_pid=2242 prev_prio=120 prev_state=R ==> next_comm=kworker/5:1 next_pid=60 next_prio=120
+[...]
+          <idle>-0     [002] d...  2440.707230: sched_switch: prev_comm=swapper/2 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=snapshot-test-2 next_pid=2229 next_prio=120
+
+ # cat trace
+# tracer: nop
+#
+# entries-in-buffer/entries-written: 77/77   #P:8
+#
+#                              _-----=> irqs-off
+#                             / _----=> need-resched
+#                            | / _---=> hardirq/softirq
+#                            || / _--=> preempt-depth
+#                            ||| /     delay
+#           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
+#              | |       |   ||||       |         |
+          <idle>-0     [007] d...  2440.707395: sched_switch: prev_comm=swapper/7 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=snapshot-test-2 next_pid=2243 next_prio=120
+ snapshot-test-2-2229  [002] d...  2440.707438: sched_switch: prev_comm=snapshot-test-2 prev_pid=2229 prev_prio=120 prev_state=S ==> next_comm=swapper/2 next_pid=0 next_prio=120
+[...]
+
+
+If you try to use this snapshot feature when current tracer is
+one of the latency tracers, you will get the following results.
+
+ # echo wakeup > current_tracer
+ # echo 1 > snapshot
+bash: echo: write error: Device or resource busy
+ # cat snapshot
+cat: snapshot: Device or resource busy
+
 -----------
 
 More details can be found in the source code, in the