linux-stable.git/tools/perf/util/session.c, branch linux-4.3.y

perf record: Avoid infinite loop at buildid processing with no samples

2015-09-18T15:31:40+00:00

If a session contains no events, we can get stuck in an infinite loop in
__perf_session__process_events, with a non-zero file_size and data_offset, but
a zero data_size.

In this case, we can mmap the entirety of the file (consisting of the file and
attribute headers), and fetch_mmaped_event will correctly refuse to read any
(unmapped and non-existent) event headers. This causes
__perf_session__process_events to unmap the file and retry with the exact same
parameters, getting stuck in an infinite loop.

This has been observed to result in an exit-time hang when counting
rare/unschedulable events with perf record, and can be triggered artificially
with the script below:

  ----
  #!/bin/sh
  printf "REPRO: launching perf\n";
  ./perf record -e software/config=9/ sleep 1 &
  PERF_PID=$!;
  sleep 0.002;
  kill -2 $PERF_PID;
  printf "REPRO: waiting for perf (%d) to exit...\n" "$PERF_PID";
  wait $PERF_PID;
  printf "REPRO: perf exited\n";
  ----

To avoid this, have __perf_session__process_events bail out early when
the file has no data (i.e. it has no events).

Commiter note:

I only managed to reproduce this when setting
/proc/sys/kernel/kptr_restrict to '1' and changing the code to
purposefully not process any samples and no synthesized samples, i.e.
kptr_restrict prevents 'record' from synthesizing the kernel mmaps for
vmlinux + modules and since it is a workload started from perf, we don't
synthesize mmap/comm records for existing threads.

Adrian Hunter managed to reproduce it in his environment tho.

Signed-off-by: Mark Rutland 
Tested-by: Arnaldo Carvalho de Melo 
Tested-by: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1442423929-12253-1-git-send-email-mark.rutland@arm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Rename perf_session_env to perf_env

2015-08-28T17:53:55+00:00

As it is not necessarily tied to a perf.data file and needs using in
places where a perf_session is not required.

Suggested-by: Arnaldo Carvalho de Melo 
Signed-off-by: Kan Liang 
Cc: Adrian Hunter 
Cc: Andi Kleen 
Cc: Andy Lutomirski 
Cc: Jiri Olsa 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/r/1440755289-30939-4-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add support for cycles, weight branch_info field

2015-08-06T19:29:45+00:00

cycles is a new branch_info field available on some CPUs that indicates
the time deltas between branches in the LBR.

Add a sort key and output code for the cycles to allow to display the
basic block cycles individually in perf report.

We also pass in the cycles for weight when LBRs are processed, which
allows to get global and local weight, to get an estimate of the total
cost.

And also print the cycles information for perf report -D.  I also added
printing for the previously missing LBR flags (mispredict etc.)

Signed-off-by: Andi Kleen 
Acked-by: Jiri Olsa 
Cc: Namhyung Kim 
Link: http://lkml.kernel.org/r/1437233094-12844-2-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo

perf session env: Rename exit method

2015-07-29T15:59:03+00:00

The semantic associated in tools/perf/ with foo__delete(instance) is to
release all resources referenced by 'instance' members and then release
the memory for 'instance' itself.

The perf_session_env__delete() function isn't doing this, it just does
the first part, but the space used by 'instance' itself isn't freed, as
it is embedded in a larger structure, that will be freed at other stage.

For these cases we se foo__exit(), i.e. the usage is:

 void foo__delete(foo)
 {
         if (foo) {
                 foo__exit(foo);
                 free(foo);
         }
 }

But when we have something like:

 struct bar {
         struct foo foo;
         . . .
 }

Then we can't really call foo__delete(&bar.foo), we must have this
instead:

 void bar__exit(bar)
 {
         foo__exit(&bar.foo);
         /* free other bar-> resources */
 }

 void bar__delete(bar)
 {
         if (bar) {
		bar__exit(bar);
                free(bar);
         }
 }

So just rename perf_session_env__delete() to perf_session_env__exit().

Cc: Adrian Hunter 
Cc: Borislav Petkov 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Namhyung Kim 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-djbgpcfo5udqptx3q0flwtmk@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add new PERF_RECORD_SWITCH event

2015-07-24T01:51:13+00:00

Support processing of PERF_RECORD_SWITCH events and
PERF_RECORD_SWITCH_CPU_WIDE events. There is a single
tools callback for them both so that the tool must
check the event type before using the extra members
in PERF_RECORD_SWITCH_CPU_WIDE.

There is still no way to select the events, though.
That is added in a subsequest patch.

Signed-off-by: Adrian Hunter 
Acked-by: Peter Zijlstra (Intel) 
Tested-by: Jiri Olsa 
Cc: Andi Kleen 
Cc: Mathieu Poirier 
Cc: Pawel Moll 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/r/1437471846-26995-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf header: Use argv style storage for cmdline feature data

2015-07-21T17:34:08+00:00

We will reuse argv style data in following change to display counters
header showing monitored command line.

Signed-off-by: Jiri Olsa 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1437481927-29538-12-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add reference counting for cpu_map object

2015-06-25T18:15:50+00:00

Adding refference counting for cpu_map object, so it could be easily
shared among other objects.

Using cpu_map__put instead cpu_map__delete and making cpu_map__delete
static.

Signed-off-by: Jiri Olsa 
Cc: Adrian Hunter 
Cc: Andi Kleen 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/r/1435012588-9007-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Print a newline before dumping Aggregated stats

2015-06-23T21:21:43+00:00

When dumping events with 'perf report -D' the event print always starts
with a newline (see dump_event()).

Do the same with the "Aggregated stats" print so that it is not jammed
up against the last event print.

Signed-off-by: Adrian Hunter 
Cc: Jiri Olsa 
Link: http://lkml.kernel.org/r/1435045969-15999-2-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf session: Print a newline when dumping PERF_RECORD_FINISHED_ROUND

2015-06-23T21:21:43+00:00

With 'perf report -D' the PERF_RECORD_FINISHED_ROUND event was printed
without a newline, resulting in:

	0x91a18 [0x8]: PERF_RECORD_FINISHED_ROUNDAggregated stats

Other events print their details, but PERF_RECORD_FINISHED_ROUND doesn't
have any so just add a print for a newline.

Signed-off-by: Adrian Hunter 
Cc: Jiri Olsa 
Link: http://lkml.kernel.org/r/1435045969-15999-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Configurable per thread proc map processing time out

2015-06-19T21:27:13+00:00

The time out to limit the individual proc map processing was hard code
to 500ms. This patch introduce a new option --proc-map-timeout to make
the time limit configurable.

Signed-off-by: Kan Liang 
Cc: Andi Kleen 
Cc: David Ahern 
Cc: Ying Huang 
Link: http://lkml.kernel.org/r/1434549071-25611-2-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo