linux-stable.git/tools/perf/util/session.c, branch linux-4.5.y

perf kvm record/report: 'unprocessable sample' error while recording/reporting guest data

2016-01-15T19:31:58+00:00

While recording guest samples in host using perf kvm record, it will
populate unprocessable sample error, though samples will be recorded
properly. While generating report using perf kvm report, no samples will
be processed and same error will populate. We have seen this behaviour
with upstream perf(4.4-rc3) on x86 and ppc64 hardware.

Reason behind this failure is, when it tries to fetch machine from
rb_tree of machines, it fails. As a part of tracing a bug, we figured
out that this code was incorrectly refactored in commit 54245fdc3576
("perf session: Remove wrappers to machines__find").

This patch will change the functionality such that if it can't fetch
machine in first trial, it will create one node of machine and add that to
rb_tree. So next time when it tries to fetch same machine from rb_tree,
it won't fail. Actually it was the case before refactoring of code in
aforementioned commit.

This patch is generated from acme perf/core branch.

Below I've mention an example that demonstrate the behaviour before and
after applying patch.

Before applying patch:
[Note: One needs to run guest before recording data in host]

  ravi@ravi-bangoria:~$ ./perf kvm record -a
  Warning:
  5903 unprocessable samples recorded.
  Do you have a KVM guest running and not using 'perf kvm'?
  [ perf record: Captured and wrote 1.409 MB perf.data.guest (285 samples) ]

  ravi@ravi-bangoria:~$ ./perf kvm report --stdio
  Warning:
  5903 unprocessable samples recorded.
  Do you have a KVM guest running and not using 'perf kvm'?
  # To display the perf.data header info, please use --header/--header-only options.
  #
  # Total Lost Samples: 0
  #
  # Samples: 285  of event 'cycles'
  # Event count (approx.): 88715406
  #
  # Overhead  Command  Shared Object  Symbol
  # ........  .......  .............  ......
  #

  # (For a higher level overview, try: perf report --sort comm,dso)
  #

After applying patch:

  ravi@ravi-bangoria:~$ ./perf kvm record -a
  [ perf record: Captured and wrote 1.188 MB perf.data.guest (17 samples) ]

  ravi@ravi-bangoria:~$ ./perf kvm report --stdio
  # To display the perf.data header info, please use --header/--header-only options.
  #
  # Total Lost Samples: 0
  #
  # Samples: 17  of event 'cycles'
  # Event count (approx.): 700746
  #
  # Overhead  Command  Shared Object     Symbol
  # ........  .......  ................  ......................
  #
      34.19%  :5758    [unknown]         [g] 0xffffffff818682ab
      22.79%  :5758    [unknown]         [g] 0xffffffff812dc7f8
      22.79%  :5758    [unknown]         [g] 0xffffffff818650d0
      14.83%  :5758    [unknown]         [g] 0xffffffff8161a1b6
       2.49%  :5758    [unknown]         [g] 0xffffffff818692bf
       0.48%  :5758    [unknown]         [g] 0xffffffff81869253
       0.05%  :5758    [unknown]         [g] 0xffffffff81869250

Signed-off-by: Ravi Bangoria 
Cc: Naveen N. Rao 
Cc: stable@vger.kernel.org # v3.19+
Fixes: 54245fdc3576 ("perf session: Remove wrappers to machines__find")
Link: http://lkml.kernel.org/r/1449471302-11283-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf stat record: Initialize record features

2015-12-17T18:15:17+00:00

Disabling all non stat related features.

Also as we now enable STAT feature in the data file, adding code to
instruct session open to skip sample type checking for stat data files.

Signed-off-by: Jiri Olsa 
Tested-by: Arnaldo Carvalho de Melo 
Tested-by: Kan Liang 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1446734469-11352-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf report: Display newly added events in raw dump

2015-12-17T18:15:13+00:00

The 'perf report -D' command will now display detailed output for these
newly added events:

  event_update
  thread_map
  cpu_map
  stat
  stat_config
  stat_round

Signed-off-by: Jiri Olsa 
Tested-by: Kan Liang 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1445784728-21732-27-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add event_update user level event

2015-12-17T18:10:16+00:00

It'll serve as a base event for additional event attributes details,
that are not part of the attr event.

At the moment this event is just a dummy one without any specific
functionality. The type value will distinguish the update event details.
It'll come in the following patches.

The idea for this event is to be extensible for any update that the
event might need in the future.

Signed-off-by: Jiri Olsa 
Tested-by: Kan Liang 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1445784728-21732-21-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add stat round user level event

2015-12-17T17:55:43+00:00

Adding the stat round event to be stored after each stat interval round,
so that report tools (report/script) gets notified and process interval
data.

Signed-off-by: Jiri Olsa 
Tested-by: Kan Liang 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1445784728-21732-18-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add stat user level event

2015-12-17T17:38:20+00:00

Adding a stat event to store a 'struct perf_counter_values' for a given
event/cpu/thread.

Signed-off-by: Jiri Olsa 
Tested-by: Kan Liang 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1445784728-21732-15-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add stat config user level event

2015-12-17T17:38:18+00:00

Adding the stat config event to pass/store stat config data, so report
tools (report/script) know how to interpret stat data.

The config data is stored in a 'tag|value' way to allow for easy
extension and backwards compatibility.

Signed-off-by: Jiri Olsa 
Tested-by: Kan Liang 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1445784728-21732-12-git-send-email-jolsa@kernel.org
[ stat_config_term_event -> stat_config_event_entry ]
Signed-off-by: Arnaldo Carvalho de Melo

perf cpu_map: Add cpu_map user level event

2015-12-17T17:38:17+00:00

Adding the cpu_map event to pass/store cpu maps as data in
a pipe/perf.data.

We store maps in 2 formats:
  - list of cpus
  - mask of cpus

The format that takes less space is selected transparently in the
following patch.

The interface is made generic, so we could add the cpumap event data
into another event in the following patches.

Signed-off-by: Jiri Olsa 
Tested-by: Kan Liang 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1445784728-21732-8-git-send-email-jolsa@kernel.org
[ cpu_map_data_cpus -> cpu_map_entries, cpu_map_data_mask -> cpu_map_mask ]
Signed-off-by: Arnaldo Carvalho de Melo

perf thread_map: Add thread_map user level event

2015-12-17T17:38:16+00:00

Adding the thread_map event to pass/store thread maps as data in
the pipe/perf.data.

Storing the thread ID along with the standard comm[16] thread name string.

Signed-off-by: Jiri Olsa 
Tested-by: Kan Liang 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1445784728-21732-4-git-send-email-jolsa@kernel.org
[ Renamed thread_map_data_event to thread_map_event_entry ]
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Make perf_session__register_idle_thread drop the refcount

2015-12-10T19:28:58+00:00

Note that since the thread was already inserted to the session
list, it will be released when the session is released.
Also, in perf_session__register_idle_thread() failure path,
the thread should be put before returning.

Refcnt debugger shows that the perf_session__register_idle_thread
gets the returned thread, but the caller (__cmd_top) does not
put the returned idle thread.

  ----
  ==== [0] ====
  Unreclaimed thread@0x24e6240
  Refcount +1 => 0 at
    ./perf(thread__new+0xe5) [0x4c8a75]
    ./perf(machine__findnew_thread+0x9a) [0x4bbdba]
    ./perf(perf_session__register_idle_thread+0x28) [0x4c63c8]
    ./perf(cmd_top+0xd7d) [0x43cf6d]
    ./perf() [0x47ba35]
    ./perf(main+0x617) [0x4225b7]
    /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f06027c5af5]
    ./perf() [0x42272d]
  Refcount +1 => 1 at
    ./perf(thread__get+0x2c) [0x4c8bcc]
    ./perf(machine__findnew_thread+0xee) [0x4bbe0e]
    ./perf(perf_session__register_idle_thread+0x28) [0x4c63c8]
    ./perf(cmd_top+0xd7d) [0x43cf6d]
    ./perf() [0x47ba35]
    ./perf(main+0x617) [0x4225b7]
    /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f06027c5af5]
    ./perf() [0x42272d]
  Refcount +1 => 2 at
    ./perf(thread__get+0x2c) [0x4c8bcc]
    ./perf(machine__findnew_thread+0x112) [0x4bbe32]
    ./perf(perf_session__register_idle_thread+0x28) [0x4c63c8]
    ./perf(cmd_top+0xd7d) [0x43cf6d]
    ./perf() [0x47ba35]
    ./perf(main+0x617) [0x4225b7]
    /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f06027c5af5]
    ./perf() [0x42272d]
  ----

Signed-off-by: Masami Hiramatsu 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20151209021122.10245.69707.stgit@localhost.localdomain
[ Drop the refcount in perf_session__register_idle_thread() ]
Signed-off-by: Arnaldo Carvalho de Melo