linux.git/Documentation/trace, branch v4.8

tracing: expose current->comm to [ku]probe events

2016-06-20T13:54:19+00:00

ftrace is very quick to give up on saving the task command line (see
`trace_save_cmdline()`). The workaround for events which really care
about the command line is to explicitly assign it as part of the entry.
However, this doesn't work for kprobe events, as there's no
straightforward way to get access to current->comm. Add a kprobe/uprobe
event variable $comm which provides exactly that.

Link: http://lkml.kernel.org/r/f59b472033b943a370f5f48d0af37698f409108f.1465435894.git.osandov@fb.com

Acked-by: Masami Hiramatsu 
Signed-off-by: Omar Sandoval 
Signed-off-by: Steven Rostedt

Merge tag 'char-misc-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

2016-05-21T04:20:31+00:00

Pull char / misc driver updates from Greg KH:
 "Here's the big char and misc driver update for 4.7-rc1.

  Lots of different tiny driver subsystems have updates here with new
  drivers and functionality.  Details in the shortlog.

  All have been in linux-next with no reported issues for a while"

* tag 'char-misc-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (125 commits)
  mcb: Delete num_cells variable which is not required
  mcb: Fixed bar number assignment for the gdd
  mcb: Replace ioremap and request_region with the devm version
  mcb: Implement bus->dev.release callback
  mcb: export bus information via sysfs
  mcb: Correctly initialize the bus's device
  mei: bus: call mei_cl_read_start under device lock
  coresight: etb10: adjust read pointer only when needed
  coresight: configuring ETF in FIFO mode when acting as link
  coresight: tmc: implementing TMC-ETF AUX space API
  coresight: moving struct cs_buffers to header file
  coresight: tmc: keep track of memory width
  coresight: tmc: make sysFS and Perf mode mutually exclusive
  coresight: tmc: dump system memory content only when needed
  coresight: tmc: adding mode of operation for link/sinks
  coresight: tmc: getting rid of multiple read access
  coresight: tmc: allocating memory when needed
  coresight: tmc: making prepare/unprepare functions generic
  coresight: tmc: splitting driver in ETB/ETF and ETR components
  coresight: tmc: cleaning up header file
  ...

Merge tag 'trace-v4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2016-05-19T01:55:19+00:00

Pull tracing updates from Steven Rostedt:
 "This includes two new updates for the ftrace infrastructure.

   - With the changing of the code for filtering events by pid, from a
     list of pids to a bitmask, we can now easily implement following
     forks.  With a new tracing option "event-fork" which, when set,
     will have tasks with pids in set_event_pid, when they fork, to have
     their child pids added to set_event_pid and the child will be
     traced as well.

     Note, if "event-fork" is set and a task with its pid in
     set_event_pid exits, its pid will be removed from set_event_pid

   - The addition of Tom Zanussi's hist triggers.  This includes a very
     thorough documentatino on how to use the hist triggers with events.
     This introduces a quick and easy way to get histogram data from
     events and their fields.

  Some other cleanups and updates were added as well.  Like Masami
  Hiramatsu added test cases for the event trigger and hist triggers.
  Also I added a speed up of filtering by using a temp buffer when
  filters are set"

* tag 'trace-v4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (45 commits)
  tracing: Use temp buffer when filtering events
  tracing: Remove TRACE_EVENT_FL_USE_CALL_FILTER logic
  tracing: Remove unused function trace_current_buffer_lock_reserve()
  tracing: Remove one use of trace_current_buffer_lock_reserve()
  tracing: Have trace_buffer_unlock_commit() call the _regs version with NULL
  tracing: Remove unused function trace_current_buffer_discard_commit()
  tracing: Move trace_buffer_unlock_commit{_regs}() to local header
  tracing: Fold filter_check_discard() into its only user
  tracing: Make filter_check_discard() local
  tracing: Move event_trigger_unlock_commit{_regs}() to local header
  tracing: Don't use the address of the buffer array name in copy_from_user
  tracing: Handle tracing_map_alloc_elts() error path correctly
  tracing: Add check for NULL event field when creating hist field
  tracing: checking for NULL instead of IS_ERR()
  tracing: Do not inherit event-fork option for instances
  tracing: Fix unsigned comparison to zero in hist trigger code
  kselftests/ftrace: Add a test for log2 modifier of hist trigger
  tracing: Add hist trigger 'log2' modifier
  kselftests/ftrace: Add hist trigger testcases
  kselftests/ftrace : Add event trigger testcases
  ...

coresight: stm: adding driver for CoreSight STM component

2016-05-03T21:59:30+00:00

This driver adds support for the STM CoreSight IP block, allowing any
system compoment (HW or SW) to log and aggregate messages via a
single entity.

The CoreSight STM exposes an application defined number of channels
called stimulus port.  Configuration is done using entries in sysfs
and channels made available to userspace via configfs.

Signed-off-by: Pratik Patel 
Signed-off-by: Mathieu Poirier 
Reviewed-by: Michael Williams 
Signed-off-by: Chunyan Zhang 
Signed-off-by: Greg Kroah-Hartman

sched/fair: Gather CPU load functions under a more conventional namespace

2016-04-23T12:20:41+00:00

The CPU load update related functions have a weak naming convention
currently, starting with update_cpu_load_*() which isn't ideal as
"update" is a very generic concept.

Since two of these functions are public already (and a third is to come)
that's enough to introduce a more conventional naming scheme. So let's
do the following rename instead:

	update_cpu_load_*() -> cpu_load_update_*()

Signed-off-by: Frederic Weisbecker 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Byungchul Park 
Cc: Chris Metcalf 
Cc: Christoph Lameter 
Cc: Luiz Capitulino 
Cc: Mike Galbraith 
Cc: Paul E . McKenney 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/1460555812-25375-2-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar

tracing: Add support for named hist triggers

2016-04-19T22:56:01+00:00

Allow users to define 'named' hist triggers.  All triggers created
with the same 'name=xxx' option will update the same shared histogram
data.

This expands the hist trigger syntax from this:

    # echo hist:keys=xxx ... [ if filter] > event/trigger

to this:

    # echo hist:name=xxx:keys=xxx ... [ if filter] > event/trigger

Named histograms must use a 'compatible' set of keys and values, which
means each event added to a set of named triggers must have the same
names and types.

Reading the 'hist' file of any of the participating events will
produce the same output as any other participating event, which is to
be expected since they share the same data.

Link: http://lkml.kernel.org/r/1dbc84ee3322a75daaf5b3ef1d0cc0a2fb682fc7.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi 
Tested-by: Masami Hiramatsu 
Reviewed-by: Namhyung Kim 
Signed-off-by: Steven Rostedt

tracing: Add support for multiple hist triggers per event

2016-04-19T22:55:59+00:00

Allow users to define any number of hist triggers per trace event.
Any number of hist triggers may be added for a given event, which may
differ by key, value, or filter.

Reading the event's 'hist' file will display the output of all the
hist triggers defined on an event concatenated in the order they were
defined.

Link: http://lkml.kernel.org/r/48a0c8dd34c344571de880fb35e211c6d9a28961.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi 
Tested-by: Masami Hiramatsu 
Reviewed-by: Namhyung Kim 
Signed-off-by: Steven Rostedt

tracing: Add 'hist' trigger Documentation

2016-04-19T22:55:58+00:00

Add documentation and usage examples for 'hist' triggers.

Link: http://lkml.kernel.org/r/2e13f35f47fea6d647f0efefccfc9673ea84b29f.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi 
Tested-by: Masami Hiramatsu 
Reviewed-by: Namhyung Kim 
Signed-off-by: Steven Rostedt

tracing: Update the documentation to describe "event-fork" option

2016-04-19T14:28:29+00:00

Add documentation to the ftrace.txt file in Documentation to describe the
event-fork option. Also add the missing "display-graph" option now that it
shows up in the trace_options file (from a previous commit).

Signed-off-by: Steven Rostedt

x86, tracing, perf: Add trace point for MSR accesses

2015-12-06T11:56:10+00:00

For debugging low level code interacting with the CPU it is often
useful to trace the MSR read/writes. This gives a concise summary of
PMU and other operations.

perf has an ad-hoc way to do this using trace_printk, but it's
somewhat limited (and also now spews ugly boot messages when enabled)

Instead define real trace points for all MSR accesses.

This adds three new trace points: read_msr and write_msr and rdpmc.

They also report if the access faulted (if *_safe is used)

This allows filtering and triggering on specific MSR values, which
allows various more advanced debugging techniques.

All the values are well defined in the CPU documentation.

The trace can be post processed with
Documentation/trace/postprocess/decode_msr.py to add symbolic MSR
names to the trace.

I only added it to native MSR accesses in C, not paravirtualized or in
entry*.S (which is not too interesting)

Originally the patch kit moved the MSRs out of line.  This uses an
alternative approach recommended by Steven Rostedt of only moving the
trace calls out of line, but open coding the access to the jump label.

Signed-off-by: Andi Kleen 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Steven Rostedt 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Thomas Gleixner 
Cc: Vince Weaver 
Link: http://lkml.kernel.org/r/1449018060-1742-3-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar