Add documentation for new config terms.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1495786658-18063-13-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Since the unprivileged sched switch event was added in perf, PT doesn't
need need perf_event_paranoid=-1 anymore for per cpu decoding.

Add a note stating that that is only needed for kernels < 4.2.
Reported-by: NAndi Kleen <ak@linux.intel.com>
Report-Link: http://lkml.kernel.org/r/http://lkml.kernel.org/n/tip-x2ybghpqxxn3zu0m8o7qi42r@git.kernel.orgAcked-by: NAdrian Hunter <adrian.hunter@intel.com>
Fixes: 45ac1403 ("perf: Add PERF_RECORD_SWITCH to indicate context switches")
Link: http://lkml.kernel.org/n/tip-x2ybghpqxxn3zu0m8o7qi42r@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

When using 'perf script' to look at PT traces it is often useful to
ignore the initialization code at the beginning.

On larger traces which may have many millions of instructions in
initialization code doing that in a pipeline can be very slow, with perf
script spending a lot of CPU time calling printf and writing data.

This patch adds an extension to the --itrace argument that skips 'n'
events (instructions, branches or transactions) at the beginning. This
is much more efficient.

v2:
Add support for BTS (Adrian Hunter)
Document in itrace.txt
Fix branch check
Check transactions and instructions too

Committer note:

To test intel_pt one needs to make sure VT-x isn't active, i.e.
stopping KVM guests on the test machine, as described by Andi Kleen
at http://lkml.kernel.org/r/20160301234953.GD23621@tassilo.jf.intel.comSigned-off-by: NAndi Kleen <ak@linux.intel.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1459187142-20035-1-git-send-email-andi@firstfloor.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

autofdo incorrectly expects branch flags to include either mispred or
predicted.  In fact mispred = predicted = 0 is valid and means the flags
are not supported, which they aren't by Intel PT.

To make autofdo work, add a config option which will cause Intel PT
decoder to set the mispred flag on all branches.

Below is an example of using Intel PT with autofdo.  The example is
also added to the Intel PT documentation.  It requires autofdo
(https://github.com/google/autofdo) and gcc version 5.  The bubble
sort example is from the AutoFDO tutorial (https://gcc.gnu.org/wiki/AutoFDO/Tutorial)
amended to take the number of elements as a parameter.

	$ gcc-5 -O3 sort.c -o sort_optimized
	$ ./sort_optimized 30000
	Bubble sorting array of 30000 elements
	2254 ms

	$ cat ~/.perfconfig
	[intel-pt]
		mispred-all

	$ perf record -e intel_pt//u ./sort 3000
	Bubble sorting array of 3000 elements
	58 ms
	[ perf record: Woken up 2 times to write data ]
	[ perf record: Captured and wrote 3.939 MB perf.data ]
	$ perf inject -i perf.data -o inj --itrace=i100usle --strip
	$ ./create_gcov --binary=./sort --profile=inj --gcov=sort.gcov -gcov_version=1
	$ gcc-5 -O3 -fauto-profile=sort.gcov sort.c -o sort_autofdo
	$ ./sort_autofdo 30000
	Bubble sorting array of 30000 elements
	2155 ms

Note there is currently no advantage to using Intel PT instead of LBR,
but that may change in the future if greater use is made of the data.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1443186956-18718-26-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Add support for generating branch stack context for PT samples.  The
decoder reports a configurable number of branches as branch context for
each sample. Internally it keeps track of them by using a simple sliding
window.  We also flush the last branch buffer on each sample to avoid
overlapping intervals.

This is useful for:

- Reporting accurate basic block edge frequencies through the perf
  report branch view
- Using with --branch-history to get the wider context of samples
- Other users of LBRs

Also the Documentation is updated.

Examples:

	Record with Intel PT:

		perf record -e intel_pt//u ls

	Branch stacks are used by default if synthesized so:

		perf report --itrace=ile

	is the same as:

		perf report --itrace=ile -b

	Branch history can be requested also:

		perf report --itrace=igle --branch-history
Based-on-patch-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1443186956-18718-15-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Instruction tracing options (i.e. --itrace) include an option for
sampling instructions at an arbitrary period. e.g.

	--itrace=i10us

means make an 'instructions' sample for every 10us of trace.

Currently the logic does not distinguish between a period of
zero and no period being specified at all, so it gets treated
as the default period which is 100000.  That doesn't really
make sense.

Fix it so that zero period is accepted and treated as meaning
"as often as possible".

In the case of Intel PT that is the same as a period of 1 and
a unit of 'instructions' (i.e. --itrace=i1i).
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1443186956-18718-2-git-send-email-adrian.hunter@intel.com
[ Add a few lines describing this in the Documentation/intel-pt.txt file ]
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

no_force_psb was dropped as a late change to the kernel driver.
Consequently, remove it from the documentation.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1443089122-19082-2-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Update Intel PT documentation to describe new features.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-26-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

To record an AUX area, the weak function auxtrace_record__init() must be
implemented.

Equally to decode an AUX area, the AUX area tracing type must be added
to the perf_event__process_auxtrace_info() function.

This patch makes those two changes plus hooks up default config for the
intel_pt PMU.  Also some brief documentation is provided for using the
tools with intel_pt.

Commiter note:

E.g:

  [root@perf4 ~]# dmesg
  451 [0.405807] Performance Events: PEBS fmt2+, 16-deep LBR, Broadwell events, full-width counters, Intel PMU driver.
  [root@perf4 ~]# perf --version
  perf version 4.1.g53874a
  [root@perf4 ~]#  perf record -e intel_pt//u -a sleep 10
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.383 MB perf.data ]
  [root@perf4 ~]# perf evlist
  intel_pt//u
  sched:sched_switch
  dummy:u
  [root@perf4 ~]# perf report --stdio
  # To display the perf.data header info, please use --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 0  of event 'intel_pt//u'
  # Event count (approx.): 0
  #
  # Overhead  Command  Shared Object  Symbol
  # ........  .......  .............  ......
  #

  # Samples: 393  of event 'sched:sched_switch'
  # Event count (approx.): 393
  #
  # Overhead  Command         Shared Object     Symbol
  # ........  ..............  ................  ..............
    49.62%  swapper         [kernel.vmlinux]  [k] __schedule
    10.69%  rcu_sched       [kernel.vmlinux]  [k] __schedule
     6.62%  rcuos/0         [kernel.vmlinux]  [k] __schedule
     5.60%  kworker/0:1     [kernel.vmlinux]  [k] __schedule
     3.56%  rcuos/3         [kernel.vmlinux]  [k] __schedule
     3.05%  kworker/u384:2  [kernel.vmlinux]  [k] __schedule
     2.54%  kworker/2:0     [kernel.vmlinux]  [k] __schedule
     2.54%  tuned           [kernel.vmlinux]  [k] __schedule
  <SNIP>
  # Samples: 0  of event 'dummy:u'
  # Event count (approx.): 0
  #
  # Overhead  Command  Shared Object  Symbol
  # ........  .......  .............  ......

  # Samples: 28  of event 'instructions:u'
  # Event count (approx.): 5030172
  #
  # Overhead  Command     Shared Object        Symbol
  # ........  ..........  ...................  ................................
  #
    21.43%  tuned       libpython2.7.so.1.0  [.] PyEval_EvalFrameEx
                 |
                 ---PyEval_EvalFrameEx
                    |
                    |--83.33%-- PyEval_EvalCodeEx
                    |          PyEval_EvalFrameEx
                    |          |
                    |          |--60.00%-- PyEval_EvalCodeEx
                    |          |          PyEval_EvalFrameEx
                    |          |          PyEval_EvalFrameEx
                    |          |
                    |           --40.00%-- PyEval_EvalFrameEx
                    |
                     --16.67%-- PyEval_EvalFrameEx
                               PyEval_EvalCodeEx
                               PyEval_EvalFrameEx
                               PyEval_EvalCodeEx
                               PyEval_EvalFrameEx
                               PyEval_EvalFrameEx

    14.29%  tuned       libpython2.7.so.1.0  [.] _PyType_Lookup
                 |
                 ---_PyType_Lookup
                    _PyObject_GenericGetAttrWithDict
                    PyEval_EvalFrameEx
                    PyEval_EvalCodeEx
                    PyEval_EvalFrameEx
                    PyEval_EvalCodeEx
                    PyEval_EvalFrameEx
                    |
                    |--75.00%-- PyEval_EvalFrameEx
                    |
                     --25.00%-- PyEval_EvalCodeEx
                               PyEval_EvalFrameEx
                               PyEval_EvalFrameEx

     3.57%  irqbalance  irqbalance           [.] 0x0000000000004038
            |
            ---0x4038
               0x4761
               0x4761
               0x4761
               0x49f1
               0x2295

     3.57%  irqbalance  libc-2.17.so         [.] __GI_____strtoull_l_internal
            |
            ---__GI_____strtoull_l_internal
               0x6f49
               0x229a

     3.57%  irqbalance  libc-2.17.so         [.] __strchrnul
            |
            ---__strchrnul
               vfprintf
               __vsprintf_chk
               __sprintf_chk
               0x2724
               0x4038
               0x2331

     3.57%  irqbalance  libc-2.17.so         [.] __strstr_sse42
            |
            ---__strstr_sse42
               0x71e0
               0x229f

  # And now to some userspace ftrace on uninstrumented binaries 8-) :
  # Hand edited to make it a bit more compact, replacing /home/acme/bin/perf
  # with /bin/perf:

  [root@perf4 ~]# perf script
     perf 8921 [3] 7.310889: 1 branches:u:            0 [unknown] ([unknown]) => 7fcecadbf257 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.310889: 1 branches:u: 7fcecadbf25f __GI___ioctl (/usr/lib64/libc-2.17.so) => 481689 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310889: 1 branches:u:       481694 perf_evlist__enable (/bin/perf) => 481614 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310889: 1 branches:u:       481630 perf_evlist__enable (/bin/perf) => 4816d8 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310889: 1 branches:u:       4816de perf_evlist__enable (/bin/perf) => 48164f perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310889: 1 branches:u:       481652 perf_evlist__enable (/bin/perf) => 48165f perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310889: 1 branches:u:       481684 perf_evlist__enable (/bin/perf) => 41d250 ioctl@plt (/bin/perf)
     perf 8921 [3] 7.310889: 1 branches:u:       41d250 ioctl@plt (/bin/perf) => 7fcecadbf250 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.310889: 1 branches:u: 7fcecadbf255 __GI___ioctl (/usr/lib64/libc-2.17.so) => 0 [unknown] ([unknown])
     perf 8921 [3] 7.310890: 1 branches:u:            0 [unknown] ([unknown]) => 7fcecadbf257 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.310890: 1 branches:u: 7fcecadbf25f __GI___ioctl (/usr/lib64/libc-2.17.so) => 481689 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310890: 1 branches:u:       481694 perf_evlist__enable (/bin/perf) => 481614 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310890: 1 branches:u:       481652 perf_evlist__enable (/bin/perf) => 48165f perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310890: 1 branches:u:       481684 perf_evlist__enable (/bin/perf) => 41d250 ioctl@plt (/bin/perf)
     perf 8921 [3] 7.310890: 1 branches:u:       41d250 ioctl@plt (/bin/perf) => 7fcecadbf250 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.310890: 1 branches:u: 7fcecadbf255 __GI___ioctl (/usr/lib64/libc-2.17.so) => 0 [unknown] ([unknown])
     perf 8921 [3] 7.310893: 1 branches:u:            0 [unknown] ([unknown]) => 7fcecadbf257 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.310893: 1 branches:u: 7fcecadbf25f __GI___ioctl (/usr/lib64/libc-2.17.so) => 481689 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310893: 1 branches:u:       4816a8 perf_evlist__enable (/bin/perf) => 4815f8 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310893: 1 branches:u:       4815fe perf_evlist__enable (/bin/perf) => 481614 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310893: 1 branches:u:       481652 perf_evlist__enable (/bin/perf) => 48165f perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310893: 1 branches:u:       481684 perf_evlist__enable (/bin/perf) => 41d250 ioctl@plt (/bin/perf)
     perf 8921 [3] 7.310893: 1 branches:u:       41d250 ioctl@plt (/bin/perf) => 7fcecadbf250 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.310893: 1 branches:u: 7fcecadbf255 __GI___ioctl (/usr/lib64/libc-2.17.so) => 0 [unknown] ([unknown])
     perf 8921 [3] 7.310956: 1 branches:u:            0 [unknown] ([unknown]) => 7fcecadbf257 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.310956: 1 branches:u: 7fcecadbf25f __GI___ioctl (/usr/lib64/libc-2.17.so) => 481689 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310956: 1 branches:u:       481694 perf_evlist__enable (/bin/perf) => 481614 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310956: 1 branches:u:       481630 perf_evlist__enable (/bin/perf) => 4816d8 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310956: 1 branches:u:       4816de perf_evlist__enable (/bin/perf) => 48164f perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310956: 1 branches:u:       481652 perf_evlist__enable (/bin/perf) => 48165f perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310956: 1 branches:u:       481684 perf_evlist__enable (/bin/perf) => 41d250 ioctl@plt (/bin/perf)
     perf 8921 [3] 7.310956: 1 branches:u:       41d250 ioctl@plt (/bin/perf) => 7fcecadbf250 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.310956: 1 branches:u: 7fcecadbf255 __GI___ioctl (/usr/lib64/libc-2.17.so) => 0 [unknown] ([unknown])
     perf 8921 [3] 7.310961: 1 branches:u:            0 [unknown] ([unknown]) => 7fcecadbf257 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.310961: 1 branches:u: 7fcecadbf25f __GI___ioctl (/usr/lib64/libc-2.17.so) => 481689 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310961: 1 branches:u:       481694 perf_evlist__enable (/bin/perf) => 481614 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310961: 1 branches:u:       481652 perf_evlist__enable (/bin/perf) => 48165f perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310961: 1 branches:u:       481684 perf_evlist__enable (/bin/perf) => 41d250 ioctl@plt (/bin/perf)
     perf 8921 [3] 7.310961: 1 branches:u:       41d250 ioctl@plt (/bin/perf) => 7fcecadbf250 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.310961: 1 branches:u: 7fcecadbf255 __GI___ioctl (/usr/lib64/libc-2.17.so) => 0 [unknown] ([unknown])
     perf 8921 [3] 7.310968: 1 branches:u:            0 [unknown] ([unknown]) => 7fcecadbf257 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.310968: 1 branches:u: 7fcecadbf25f __GI___ioctl (/usr/lib64/libc-2.17.so) => 481689 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310968: 1 branches:u:       4816a8 perf_evlist__enable (/bin/perf) => 4815f8 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310968: 1 branches:u:       4815fe perf_evlist__enable (/bin/perf) => 481614 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310968: 1 branches:u:       481652 perf_evlist__enable (/bin/perf) => 48165f perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.310968: 1 branches:u:       481684 perf_evlist__enable (/bin/perf) => 41d250 ioctl@plt (/bin/perf)
     perf 8921 [3] 7.310968: 1 branches:u:       41d250 ioctl@plt (/bin/perf) => 7fcecadbf250 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.310968: 1 branches:u: 7fcecadbf255 __GI___ioctl (/usr/lib64/libc-2.17.so) => 0 [unknown] ([unknown])
     perf 8921 [3] 7.311040: 1 branches:u:            0 [unknown] ([unknown]) => 7fcecadbf257 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.311040: 1 branches:u: 7fcecadbf25f __GI___ioctl (/usr/lib64/libc-2.17.so) => 481689 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.311040: 1 branches:u:       481694 perf_evlist__enable (/bin/perf) => 481614 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.311040: 1 branches:u:       481630 perf_evlist__enable (/bin/perf) => 4816d8 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.311040: 1 branches:u:       4816de perf_evlist__enable (/bin/perf) => 48164f perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.311040: 1 branches:u:       481652 perf_evlist__enable (/bin/perf) => 48165f perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.311040: 1 branches:u:       481684 perf_evlist__enable (/bin/perf) => 41d250 ioctl@plt (/bin/perf)
     perf 8921 [3] 7.311040: 1 branches:u:       41d250 ioctl@plt (/bin/perf) => 7fcecadbf250 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.311040: 1 branches:u: 7fcecadbf255 __GI___ioctl (/usr/lib64/libc-2.17.so) => 0 [unknown] ([unknown])
     perf 8921 [3] 7.311046: 1 branches:u:            0 [unknown] ([unknown]) => 7fcecadbf257 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.311046: 1 branches:u: 7fcecadbf25f __GI___ioctl (/usr/lib64/libc-2.17.so) => 481689 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.311046: 1 branches:u:       481694 perf_evlist__enable (/bin/perf) => 481614 perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.311046: 1 branches:u:       481652 perf_evlist__enable (/bin/perf) => 48165f perf_evlist__enable (/bin/perf)
     perf 8921 [3] 7.311046: 1 branches:u:       481684 perf_evlist__enable (/bin/perf) => 41d250 ioctl@plt (/bin/perf)
     perf 8921 [3] 7.311046: 1 branches:u:       41d250 ioctl@plt (/bin/perf) => 7fcecadbf250 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.311046: 1 branches:u: 7fcecadbf255 __GI___ioctl (/usr/lib64/libc-2.17.so) => 0 [unknown] ([unknown])
     perf 8921 [3] 7.311050: 1 branches:u:            0 [unknown] ([unknown]) => 7fcecadbf257 __GI___ioctl (/usr/lib64/libc-2.17.so)
     perf 8921 [3] 7.311050: 1 branches:u: 7fcecadbf25f __GI___ioctl (/usr/lib64/libc-2.17.so) => 481689 perf_evlist__enable (/bin/perf)
:
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-8-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>