user/sven/linux.git/kernel/trace/trace_events.c, branch v4.9.5

tracing: Show the preempt count of when the event was called

2016-06-20T13:54:21Z

Because tracepoint callbacks are done with preemption enabled, the trace events are always called with preempt disable due to the rcu_read_lock_sched_notrace() in __DO_TRACE(). This causes the preempt count shown in the recorded trace event to be inaccurate. It is always one more that what the preempt_count was when the tracepoint was called. If CONFIG_PREEMPT is enabled, subtract 1 from the preempt_count before recording it in the trace buffer. Link: http://lkml.kernel.org/r/20160525132537.GA10808@linutronix.de Reported-by: Sebastian Andrzej Siewior Signed-off-by: Steven Rostedt

tracing: Move pid_list write processing into its own function

2016-06-20T13:54:18Z

The addition of PIDs into a pid_list via the write operation of set_event_pid is a bit complex. The same operation will be needed for function tracing pids. Move the code into its own generic function in trace.c, so that we can avoid duplication of this code. Signed-off-by: Steven Rostedt

tracing: Move the pid_list seq_file functions to be global

2016-06-20T13:54:17Z

To allow other aspects of ftrace to use the pid_list logic, we need to reuse the seq_file functions. Making the generic part into functions that can be called by other files will help in this regard. Signed-off-by: Steven Rostedt

tracing: Move filtered_pid helper functions into trace.c

2016-06-20T13:54:17Z

As the filtered_pid functions are going to be used by function tracer as well as trace_events, move the code into the generic trace.c file. The functions moved are: trace_find_filtered_pid() trace_ignore_this_task() trace_filter_add_remove_task() Kernel Doc text was also added. Signed-off-by: Steven Rostedt

tracing: Make the pid filtering helper functions global

2016-06-20T13:54:16Z

Make the functions used for pid filtering global for tracing, such that the function tracer can use the pid code as well. Signed-off-by: Steven Rostedt

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

2016-05-19T01:55:19Z

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 ...

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2016-05-09T19:59:24Z

In netdevice.h we removed the structure in net-next that is being changes in 'net'. In macsec.c and rtnetlink.c we have overlaps between fixes in 'net' and the u64 attribute changes in 'net-next'. The mlx5 conflicts have to do with vxlan support dependencies. Signed-off-by: David S. Miller

tracing: Use temp buffer when filtering events

2016-05-03T21:59:24Z

Filtering of events requires the data to be written to the ring buffer before it can be decided to filter or not. This is because the parameters of the filter are based on the result that is written to the ring buffer and not on the parameters that are passed into the trace functions. The ftrace ring buffer is optimized for writing into the ring buffer and committing. The discard procedure used when filtering decides the event should be discarded is much more heavy weight. Thus, using a temporary filter when filtering events can speed things up drastically. Without a temp buffer we have: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.790706626 seconds time elapsed ( +- 0.71% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.566904059 seconds time elapsed ( +- 0.27% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.690598511 seconds time elapsed ( +- 0.19% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.707486364 seconds time elapsed ( +- 0.30% ) The first run above is without any tracing, just to get a based figure. hackbench takes ~0.79 seconds to run on the system. The second run enables tracing all events where nothing is filtered. This increases the time by 100% and hackbench takes 1.57 seconds to run. The third run filters all events where the preempt count will equal "20" (this should never happen) thus all events are discarded. This takes 1.69 seconds to run. This is 10% slower than just committing the events! The last run enables all events and filters where the filter will commit all events, and this takes 1.70 seconds to run. The filtering overhead is approximately 10%. Thus, the discard and commit of an event from the ring buffer may be about the same time. With this patch, the numbers change: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.778233033 seconds time elapsed ( +- 0.38% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.582102692 seconds time elapsed ( +- 0.28% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.309230710 seconds time elapsed ( +- 0.22% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.786001924 seconds time elapsed ( +- 0.20% ) The first run is again the base with no tracing. The second run is all tracing with no filtering. It is a little slower, but that may be well within the noise. The third run shows that discarding all events only took 1.3 seconds. This is a speed up of 23%! The discard is much faster than even the commit. The one downside is shown in the last run. Events that are not discarded by the filter will take longer to add, this is due to the extra copy of the event. Cc: Alexei Starovoitov Signed-off-by: Steven Rostedt

tracing: Don't display trigger file for events that can't be enabled

2016-05-03T16:59:30Z

Currently register functions for events will be called through the 'reg' field of event class directly without any check when seting up triggers. Triggers for events that don't support register through debug fs (events under events/ftrace are for trace-cmd to read event format, and most of them don't have a register function except events/ftrace/functionx) can't be enabled at all, and an oops will be hit when setting up trigger for those events, so just not creating them is an easy way to avoid the oops. Link: http://lkml.kernel.org/r/1462275274-3911-1-git-send-email-chuhu@redhat.com Cc: stable@vger.kernel.org # 3.14+ Fixes: 85f2b08268c01 ("tracing: Add basic event trigger framework") Signed-off-by: Chunyu Hu Signed-off-by: Steven Rostedt

tracing: Remove one use of trace_current_buffer_lock_reserve()

2016-04-29T22:10:21Z

The only user of trace_current_buffer_lock_reserve() is in the boot up self tests. Restructure the code a little to have that code use what everything else uses: trace_event_buffer_lock_reserve(). Signed-off-by: Steven Rostedt