1. 14 Aug, 2013 2 commits
  2. 19 Jul, 2013 1 commit
  3. 21 Jun, 2013 1 commit
    • Steven Rostedt's avatar
      tracing: Add DEFINE_EVENT_FN() macro · f5abaa1b
      Steven Rostedt authored
      
      
      Each TRACE_EVENT() adds several helper functions. If two or more trace events
      share the same structure and print format, they can also share most of these
      helper functions and save a lot of space from duplicate code. This is why the
      DECLARE_EVENT_CLASS() and DEFINE_EVENT() were created.
      
      Some events require a trigger to be called at registering and unregistering of
      the event and to do so they use TRACE_EVENT_FN().
      
      If multiple events require a trigger, they currently have no choice but to use
      TRACE_EVENT_FN() as there's no DEFINE_EVENT_FN() available. This unfortunately
      causes a lot of wasted duplicate code created.
      
      By adding a DEFINE_EVENT_FN(), these events can still use a
      DECLARE_EVENT_CLASS() and then define their own triggers.
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Link: http://lkml.kernel.org/r/51C3236C.8030508@hds.com
      
      Signed-off-by: default avatarSeiji Aguchi <seiji.aguchi@hds.com>
      Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
      f5abaa1b
  4. 13 Apr, 2013 1 commit
  5. 15 Mar, 2013 6 commits
    • Steven Rostedt (Red Hat)'s avatar
      tracing: Add a way to soft disable trace events · 417944c4
      Steven Rostedt (Red Hat) authored
      
      
      In order to let triggers enable or disable events, we need a 'soft'
      method for doing so. For example, if a function probe is added that
      lets a user enable or disable events when a function is called, that
      change must be done without taking locks or a mutex, and definitely
      it can't sleep. But the full enabling of a tracepoint is expensive.
      
      By adding a 'SOFT_DISABLE' flag, and converting the flags to be updated
      without the protection of a mutex (using set/clear_bit()), this soft
      disable flag can be used to allow critical sections to enable or disable
      events from being traced (after the event has been placed into "SOFT_MODE").
      
      Some caveats though: The comm recorder (to map pids with a comm) can not
      be soft disabled (yet). If you disable an event with with a "soft"
      disable and wait a while before reading the trace, the comm cache may be
      replaced and you'll get a bunch of <...> for comms in the trace.
      
      Reading the "enable" file for an event that is disabled will now give
      you "0*" where the '*' denotes that the tracepoint is still active but
      the event itself is "disabled".
      
      [ fixed _BIT used in & operation : thanks to Dan Carpenter and smatch ]
      
      Cc: Dan Carpenter <dan.carpenter@oracle.com>
      Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      417944c4
    • Li Zefan's avatar
      tracing: Fix some section mismatch warnings · 523c8113
      Li Zefan authored
      As we've added __init annotation to field-defining functions, we should
      add __refdata annotation to event_call variables, which reference those
      functions.
      
      Link: http://lkml.kernel.org/r/51343C1F.2050502@huawei.com
      
      Reported-by: default avatarFengguang Wu <fengguang.wu@intel.com>
      Signed-off-by: default avatarLi Zefan <lizefan@huawei.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      523c8113
    • Li Zefan's avatar
      tracing: Annotate event field-defining functions with __init · 7e4f44b1
      Li Zefan authored
      Those functions are called either during kernel boot or module init.
      
      Before:
      
      $ dmesg | grep 'Freeing unused kernel memory'
      Freeing unused kernel memory: 1208k freed
      Freeing unused kernel memory: 1360k freed
      Freeing unused kernel memory: 1960k freed
      
      After:
      
      $ dmesg | grep 'Freeing unused kernel memory'
      Freeing unused kernel memory: 1236k freed
      Freeing unused kernel memory: 1388k freed
      Freeing unused kernel memory: 1960k freed
      
      Link: http://lkml.kernel.org/r/5125877D.5000201@huawei.com
      
      Signed-off-by: default avatarLi Zefan <lizefan@huawei.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      7e4f44b1
    • Li Zefan's avatar
      tracing: Add a helper function for event print functions · f71130de
      Li Zefan authored
      Move duplicate code in event print functions to a helper function.
      
      This shrinks the size of the kernel by ~13K.
      
         text    data     bss     dec     hex filename
      6596137 1743966 10138672        18478775        119f6b7 vmlinux.o.old
      6583002 1743849 10138672        18465523        119c2f3 vmlinux.o.new
      
      Link: http://lkml.kernel.org/r/51258746.2060304@huawei.com
      
      Signed-off-by: default avatarLi Zefan <lizefan@huawei.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      f71130de
    • Steven Rostedt's avatar
      tracing: Pass the ftrace_file to the buffer lock reserve code · ccb469a1
      Steven Rostedt authored
      
      
      Pass the struct ftrace_event_file *ftrace_file to the
      trace_event_buffer_lock_reserve() (new function that replaces the
      trace_current_buffer_lock_reserver()).
      
      The ftrace_file holds a pointer to the trace_array that is in use.
      In the case of multiple buffers with different trace_arrays, this
      allows different events to be recorded into different buffers.
      
      Also fixed some of the stale comments in include/trace/ftrace.h
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      ccb469a1
    • Steven Rostedt's avatar
      tracing: Separate out trace events from global variables · ae63b31e
      Steven Rostedt authored
      
      
      The trace events for ftrace are all defined via global variables.
      The arrays of events and event systems are linked to a global list.
      This prevents multiple users of the event system (what to enable and
      what not to).
      
      By adding descriptors to represent the event/file relation, as well
      as to which trace_array descriptor they are associated with, allows
      for more than one set of events to be defined. Once the trace events
      files have a link between the trace event and the trace_array they
      are associated with, we can create multiple trace_arrays that can
      record separate events in separate buffers.
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      ae63b31e
  6. 13 Nov, 2012 1 commit
  7. 02 Nov, 2012 1 commit
    • Steven Rostedt's avatar
      tracing: Use irq_work for wake ups and remove *_nowake_*() functions · 0d5c6e1c
      Steven Rostedt authored
      
      
      Have the ring buffer commit function use the irq_work infrastructure to
      wake up any waiters waiting on the ring buffer for new data. The irq_work
      was created for such a purpose, where doing the actual wake up at the
      time of adding data is too dangerous, as an event or function trace may
      be in the midst of the work queue locks and cause deadlocks. The irq_work
      will either delay the action to the next timer interrupt, or trigger an IPI
      to itself forcing an interrupt to do the work (in a safe location).
      
      With irq_work, all ring buffer commits can safely do wakeups, removing
      the need for the ring buffer commit "nowake" variants, which were used
      by events and function tracing. All commits can now safely use the
      normal commit, and the "nowake" variants can be removed.
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      0d5c6e1c
  8. 31 Jul, 2012 1 commit
  9. 28 Jun, 2012 1 commit
    • Namhyung Kim's avatar
      tracing/kvm: Use __print_hex() for kvm_emulate_insn tracepoint · b102f1d0
      Namhyung Kim authored
      The kvm_emulate_insn tracepoint used __print_insn()
      for printing its instructions. However it makes the
      format of the event hard to parse as it reveals TP
      internals.
      
      Fortunately, kernel provides __print_hex for almost
      same purpose, we can use it instead of open coding
      it. The user-space can be changed to parse it later.
      
      That means raw kernel tracing will not be affected
      by this change:
      
       # cd /sys/kernel/debug/tracing/
       # cat events/kvm/kvm_emulate_insn/format
       name: kvm_emulate_insn
       ID: 29
       format:
      	...
       print fmt: "%x:%llx:%s (%s)%s", REC->csbase, REC->rip, __print_hex(REC->insn, REC->len), \
       __print_symbolic(REC->flags, { 0, "real" }, { (1 << 0) | (1 << 1), "vm16" }, \
       { (1 << 0), "prot16" }, { (1 << 0) | (1 << 2), "prot32" }, { (1 << 0) | (1 << 3), "prot64" }), \
       REC->failed ? " failed" : ""
      
       # echo 1 > events/kvm/kvm_emulate_insn/enable
       # cat trace
       # tracer: nop
       #
       # entries-in-buffer/entries-written: 2183/2183   #P:12
       #
       #                              _-----=> irqs-off
       #                             / _----=> need-resched
       #                            | / _---=> hardirq/softirq
       #                            || / _--=> preempt-depth
       #                            ||| /     delay
       #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
       #              | |       |   ||||       |         |
               qemu-kvm-1782  [002] ...1   140.931636: kvm_emulate_insn: 0:c102fa25:89 10 (prot32)
               qemu-kvm-1781  [004] ...1   140.931637: kvm_emulate_insn: 0:c102fa25:89 10 (prot32)
      
      Link: http://lkml.kernel.org/n/tip-wfw6y3b9ugtey8snaow9nmg5@git.kernel.org
      Link: http://lkml.kernel.org/r/1340757701-10711-2-git-send-email-namhyung@kernel.org
      
      
      
      Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Namhyung Kim <namhyung.kim@lge.com>
      Cc: kvm@vger.kernel.org
      Acked-by: default avatarAvi Kivity <avi@redhat.com>
      Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      b102f1d0
  10. 04 Oct, 2011 1 commit
  11. 26 May, 2011 1 commit
  12. 03 Feb, 2011 1 commit
    • Steven Rostedt's avatar
      tracing: Replace trace_event struct array with pointer array · e4a9ea5e
      Steven Rostedt authored
      
      
      Currently the trace_event structures are placed in the _ftrace_events
      section, and at link time, the linker makes one large array of all
      the trace_event structures. On boot up, this array is read (much like
      the initcall sections) and the events are processed.
      
      The problem is that there is no guarantee that gcc will place complex
      structures nicely together in an array format. Two structures in the
      same file may be placed awkwardly, because gcc has no clue that they
      are suppose to be in an array.
      
      A hack was used previous to force the alignment to 4, to pack the
      structures together. But this caused alignment issues with other
      architectures (sparc).
      
      Instead of packing the structures into an array, the structures' addresses
      are now put into the _ftrace_event section. As pointers are always the
      natural alignment, gcc should always pack them tightly together
      (otherwise initcall, extable, etc would also fail).
      
      By having the pointers to the structures in the section, we can still
      iterate the trace_events without causing unnecessary alignment problems
      with other architectures, or depending on the current behaviour of
      gcc that will likely change in the future just to tick us kernel developers
      off a little more.
      
      The _ftrace_event section is also moved into the .init.data section
      as it is now only needed at boot up.
      Suggested-by: default avatarDavid Miller <davem@davemloft.net>
      Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      e4a9ea5e
  13. 19 Nov, 2010 1 commit
    • Steven Rostedt's avatar
      tracing/events: Show real number in array fields · 04295780
      Steven Rostedt authored
      
      
      Currently we have in something like the sched_switch event:
      
        field:char prev_comm[TASK_COMM_LEN];	offset:12;	size:16;	signed:1;
      
      When a userspace tool such as perf tries to parse this, the
      TASK_COMM_LEN is meaningless. This is done because the TRACE_EVENT() macro
      simply uses a #len to show the string of the length. When the length is
      an enum, we get a string that means nothing for tools.
      
      By adding a static buffer and a mutex to protect it, we can store the
      string into that buffer with snprintf and show the actual number.
      Now we get:
      
        field:char prev_comm[16];       offset:12;      size:16;        signed:1;
      
      Something much more useful.
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      04295780
  14. 18 Nov, 2010 2 commits
    • Frederic Weisbecker's avatar
      tracing: Allow syscall trace events for non privileged users · 53cf810b
      Frederic Weisbecker authored
      
      
      As for the raw syscalls events, individual syscall events won't
      leak system wide information on task bound tracing. Allow non
      privileged users to use them in such workflow.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Li Zefan <lizf@cn.fujitsu.com>
      Cc: Jason Baron <jbaron@redhat.com>
      53cf810b
    • Frederic Weisbecker's avatar
      tracing: New macro to set up initial event flags value · 1ed0c597
      Frederic Weisbecker authored
      
      
      This introduces the new TRACE_EVENT_FLAGS() macro in order
      to set up initial event flags value.
      
      This macro must simply follow the definition of a trace event
      and take the event name and the flag value as parameters:
      
      TRACE_EVENT(my_event, .....
      ....
      );
      
      TRACE_EVENT_FLAGS(my_event, 1)
      
      This will set up 1 as the initial my_event->flags value.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Li Zefan <lizf@cn.fujitsu.com>
      Cc: Jason Baron <jbaron@redhat.com>
      1ed0c597
  15. 01 Aug, 2010 1 commit
  16. 21 Jul, 2010 1 commit
    • Lai Jiangshan's avatar
      tracing: Reduce latency and remove percpu trace_seq · bc289ae9
      Lai Jiangshan authored
      
      
      __print_flags() and __print_symbolic() use percpu trace_seq:
      
      1) Its memory is allocated at compile time, it wastes memory if we don't use tracing.
      2) It is percpu data and it wastes more memory for multi-cpus system.
      3) It disables preemption when it executes its core routine
         "trace_seq_printf(s, "%s: ", #call);" and introduces latency.
      
      So we move this trace_seq to struct trace_iterator.
      Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
      LKML-Reference: <4C078350.7090106@cn.fujitsu.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      bc289ae9
  17. 29 Jun, 2010 1 commit
  18. 08 Jun, 2010 1 commit
    • Frederic Weisbecker's avatar
      perf: Drop the skip argument from perf_arch_fetch_regs_caller · b0f82b81
      Frederic Weisbecker authored
      
      
      Drop this argument now that we always want to rewind only to the
      state of the first caller.
      It means frame pointers are not necessary anymore to reliably get
      the source of an event. But this also means we need this helper
      to be a macro now, as an inline function is not an option since
      we need to know when to provide a default implentation.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
      Cc: David Miller <davem@davemloft.net>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      b0f82b81
  19. 31 May, 2010 1 commit
  20. 25 May, 2010 1 commit
    • Steven Rostedt's avatar
      tracing: Add __used annotation to event variable · 49c17746
      Steven Rostedt authored
      
      
      The TRACE_EVENT() macros automate creation of trace events. To automate
      initialization, the set up variables are loaded in a special section
      that is read on boot up. GCC is not aware that these static variables
      are used and will complain about them if we do not inform GCC that
      they are indeed used.
      
      One of the declarations of the event element was missing a __used
      annotation. This patch adds it.
      Reported-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      49c17746
  21. 21 May, 2010 2 commits
  22. 18 May, 2010 1 commit
  23. 14 May, 2010 8 commits
    • Steven Rostedt's avatar
      tracing: Remove duplicate id information in event structure · 32c0edae
      Steven Rostedt authored
      
      
      Now that the trace_event structure is embedded in the ftrace_event_call
      structure, there is no need for the ftrace_event_call id field.
      The id field is the same as the trace_event type field.
      
      Removing the id and re-arranging the structure brings down the tracepoint
      footprint by another 5K.
      
         text	   data	    bss	    dec	    hex	filename
      4913961	1088356	 861512	6863829	 68bbd5	vmlinux.orig
      4895024	1023812	 861512	6780348	 6775bc	vmlinux.print
      4894944	1018052	 861512	6774508	 675eec	vmlinux.id
      Acked-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Acked-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
      Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      32c0edae
    • Steven Rostedt's avatar
      tracing: Move print functions into event class · 80decc70
      Steven Rostedt authored
      
      
      Currently, every event has its own trace_event structure. This is
      fine since the structure is needed anyway. But the print function
      structure (trace_event_functions) is now separate. Since the output
      of the trace event is done by the class (with the exception of events
      defined by DEFINE_EVENT_PRINT), it makes sense to have the class
      define the print functions that all events in the class can use.
      
      This makes a bigger deal with the syscall events since all syscall events
      use the same class. The savings here is another 30K.
      
         text	   data	    bss	    dec	    hex	filename
      4913961	1088356	 861512	6863829	 68bbd5	vmlinux.orig
      4900382	1048964	 861512	6810858	 67ecea	vmlinux.init
      4900446	1049028	 861512	6810986	 67ed6a	vmlinux.preprint
      4895024	1023812	 861512	6780348	 6775bc	vmlinux.print
      
      To accomplish this, and to let the class know what event is being
      printed, the event structure is embedded in the ftrace_event_call
      structure. This should not be an issues since the event structure
      was created for each event anyway.
      Acked-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Acked-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
      Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      80decc70
    • Steven Rostedt's avatar
      tracing: Allow events to share their print functions · a9a57763
      Steven Rostedt authored
      
      
      Multiple events may use the same method to print their data.
      Instead of having all events have a pointer to their print funtions,
      the trace_event structure now points to a trace_event_functions structure
      that will hold the way to print ouf the event.
      
      The event itself is now passed to the print function to let the print
      function know what kind of event it should print.
      
      This opens the door to consolidating the way several events print
      their output.
      
         text	   data	    bss	    dec	    hex	filename
      4913961	1088356	 861512	6863829	 68bbd5	vmlinux.orig
      4900382	1048964	 861512	6810858	 67ecea	vmlinux.init
      4900446	1049028	 861512	6810986	 67ed6a	vmlinux.preprint
      
      This change slightly increases the size but is needed for the next change.
      
      v3: Fix the branch tracer events to handle this change.
      
      v2: Fix the new function graph tracer event calls to handle this change.
      Acked-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Acked-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
      Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      a9a57763
    • Steven Rostedt's avatar
      tracing: Move raw_init from events to class · 0405ab80
      Steven Rostedt authored
      
      
      The raw_init function pointer in the event is used to initialize
      various kinds of events. The type of initialization needed is usually
      classed to the kind of event it is.
      
      Two events with the same class will always have the same initialization
      function, so it makes sense to move this to the class structure.
      
      Perhaps even making a special system structure would work since
      the initialization is the same for all events within a system.
      But since there's no system structure (yet), this will just move it
      to the class.
      
         text	   data	    bss	    dec	    hex	filename
      4913961	1088356	 861512	6863829	 68bbd5	vmlinux.orig
      4900375	1053380	 861512	6815267	 67fe23	vmlinux.fields
      4900382	1048964	 861512	6810858	 67ecea	vmlinux.init
      
      The text grew very slightly, but this is a constant growth that happened
      with the changing of the C files that call the init code.
      The bigger savings is the data which will be saved the more events share
      a class.
      Acked-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Acked-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
      Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      0405ab80
    • Steven Rostedt's avatar
      tracing: Move fields from event to class structure · 2e33af02
      Steven Rostedt authored
      
      
      Move the defined fields from the event to the class structure.
      Since the fields of the event are defined by the class they belong
      to, it makes sense to have the class hold the information instead
      of the individual events. The events of the same class would just
      hold duplicate information.
      
      After this change the size of the kernel dropped another 3K:
      
         text	   data	    bss	    dec	    hex	filename
      4913961	1088356	 861512	6863829	 68bbd5	vmlinux.orig
      4900252	1057412	 861512	6819176	 680d68	vmlinux.regs
      4900375	1053380	 861512	6815267	 67fe23	vmlinux.fields
      
      Although the text increased, this was mainly due to the C files
      having to adapt to the change. This is a constant increase, where
      new tracepoints will not increase the Text. But the big drop is
      in the data size (as well as needed allocations to hold the fields).
      This will give even more savings as more tracepoints are created.
      
      Note, if just TRACE_EVENT()s are used and not DECLARE_EVENT_CLASS()
      with several DEFINE_EVENT()s, then the savings will be lost. But
      we are pushing developers to consolidate events with DEFINE_EVENT()
      so this should not be an issue.
      
      The kprobes define a unique class to every new event, but are dynamic
      so it should not be a issue.
      
      The syscalls however have a single class but the fields for the individual
      events are different. The syscalls use a metadata to define the
      fields. I moved the fields list from the event to the metadata and
      added a "get_fields()" function to the class. This function is used
      to find the fields. For normal events and kprobes, get_fields() just
      returns a pointer to the fields list_head in the class. For syscall
      events, it returns the fields list_head in the metadata for the event.
      
      v2:  Fixed the syscall fields. The syscall metadata needs a list
           of fields for both enter and exit.
      Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Acked-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Acked-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
      Cc: Tom Zanussi <tzanussi@gmail.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      2e33af02
    • Steven Rostedt's avatar
      tracing: Remove per event trace registering · 2239291a
      Steven Rostedt authored
      
      
      This patch removes the register functions of TRACE_EVENT() to enable
      and disable tracepoints. The registering of a event is now down
      directly in the trace_events.c file. The tracepoint_probe_register()
      is now called directly.
      
      The prototypes are no longer type checked, but this should not be
      an issue since the tracepoints are created automatically by the
      macros. If a prototype is incorrect in the TRACE_EVENT() macro, then
      other macros will catch it.
      
      The trace_event_class structure now holds the probes to be called
      by the callbacks. This removes needing to have each event have
      a separate pointer for the probe.
      
      To handle kprobes and syscalls, since they register probes in a
      different manner, a "reg" field is added to the ftrace_event_class
      structure. If the "reg" field is assigned, then it will be called for
      enabling and disabling of the probe for either ftrace or perf. To let
      the reg function know what is happening, a new enum (trace_reg) is
      created that has the type of control that is needed.
      
      With this new rework, the 82 kernel events and 618 syscall events
      has their footprint dramatically lowered:
      
         text	   data	    bss	    dec	    hex	filename
      4913961	1088356	 861512	6863829	 68bbd5	vmlinux.orig
      4914025	1088868	 861512	6864405	 68be15	vmlinux.class
      4918492	1084612	 861512	6864616	 68bee8	vmlinux.tracepoint
      4900252	1057412	 861512	6819176	 680d68	vmlinux.regs
      
      The size went from 6863829 to 6819176, that's a total of 44K
      in savings. With tracepoints being continuously added, this is
      critical that the footprint becomes minimal.
      
      v5: Added #ifdef CONFIG_PERF_EVENTS around a reference to perf
          specific structure in trace_events.c.
      
      v4: Fixed trace self tests to check probe because regfunc no longer
          exists.
      
      v3: Updated to handle void *data in beginning of probe parameters.
          Also added the tracepoint: check_trace_callback_type_##call().
      
      v2: Changed the callback probes to pass void * and typecast the
          value within the function.
      Acked-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Acked-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
      Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      2239291a
    • Steven Rostedt's avatar
      tracing: Let tracepoints have data passed to tracepoint callbacks · 38516ab5
      Steven Rostedt authored
      
      
      This patch adds data to be passed to tracepoint callbacks.
      
      The created functions from DECLARE_TRACE() now need a mandatory data
      parameter. For example:
      
      DECLARE_TRACE(mytracepoint, int value, value)
      
      Will create the register function:
      
      int register_trace_mytracepoint((void(*)(void *data, int value))probe,
                                      void *data);
      
      As the first argument, all callbacks (probes) must take a (void *data)
      parameter. So a callback for the above tracepoint will look like:
      
      void myprobe(void *data, int value)
      {
      }
      
      The callback may choose to ignore the data parameter.
      
      This change allows callbacks to register a private data pointer along
      with the function probe.
      
      	void mycallback(void *data, int value);
      
      	register_trace_mytracepoint(mycallback, mydata);
      
      Then the mycallback() will receive the "mydata" as the first parameter
      before the args.
      
      A more detailed example:
      
        DECLARE_TRACE(mytracepoint, TP_PROTO(int status), TP_ARGS(status));
      
        /* In the C file */
      
        DEFINE_TRACE(mytracepoint, TP_PROTO(int status), TP_ARGS(status));
      
        [...]
      
             trace_mytracepoint(status);
      
        /* In a file registering this tracepoint */
      
        int my_callback(void *data, int status)
        {
      	struct my_struct my_data = data;
      	[...]
        }
      
        [...]
      	my_data = kmalloc(sizeof(*my_data), GFP_KERNEL);
      	init_my_data(my_data);
      	register_trace_mytracepoint(my_callback, my_data);
      
      The same callback can also be registered to the same tracepoint as long
      as the data registered is different. Note, the data must also be used
      to unregister the callback:
      
      	unregister_trace_mytracepoint(my_callback, my_data);
      
      Because of the data parameter, tracepoints declared this way can not have
      no args. That is:
      
        DECLARE_TRACE(mytracepoint, TP_PROTO(void), TP_ARGS());
      
      will cause an error.
      
      If no arguments are needed, a new macro can be used instead:
      
        DECLARE_TRACE_NOARGS(mytracepoint);
      
      Since there are no arguments, the proto and args fields are left out.
      
      This is part of a series to make the tracepoint footprint smaller:
      
         text	   data	    bss	    dec	    hex	filename
      4913961	1088356	 861512	6863829	 68bbd5	vmlinux.orig
      4914025	1088868	 861512	6864405	 68be15	vmlinux.class
      4918492	1084612	 861512	6864616	 68bee8	vmlinux.tracepoint
      
      Again, this patch also increases the size of the kernel, but
      lays the ground work for decreasing it.
      
       v5: Fixed net/core/drop_monitor.c to handle these updates.
      
       v4: Moved the DECLARE_TRACE() DECLARE_TRACE_NOARGS out of the
           #ifdef CONFIG_TRACE_POINTS, since the two are the same in both
           cases. The __DECLARE_TRACE() is what changes.
           Thanks to Frederic Weisbecker for pointing this out.
      
       v3: Made all register_* functions require data to be passed and
           all callbacks to take a void * parameter as its first argument.
           This makes the calling functions comply with C standards.
      
           Also added more comments to the modifications of DECLARE_TRACE().
      
       v2: Made the DECLARE_TRACE() have the ability to pass arguments
           and added a new DECLARE_TRACE_NOARGS() for tracepoints that
           do not need any arguments.
      Acked-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Acked-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
      Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Neil Horman <nhorman@tuxdriver.com>
      Cc: David S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      38516ab5
    • Steven Rostedt's avatar
      tracing: Create class struct for events · 8f082018
      Steven Rostedt authored
      
      
      This patch creates a ftrace_event_class struct that event structs point to.
      This class struct will be made to hold information to modify the
      events. Currently the class struct only holds the events system name.
      
      This patch slightly increases the size, but this change lays the ground work
      of other changes to make the footprint of tracepoints smaller.
      
      With 82 standard tracepoints, and 618 system call tracepoints
      (two tracepoints per syscall: enter and exit):
      
         text	   data	    bss	    dec	    hex	filename
      4913961	1088356	 861512	6863829	 68bbd5	vmlinux.orig
      4914025	1088868	 861512	6864405	 68be15	vmlinux.class
      
      This patch also cleans up some stale comments in ftrace.h.
      
      v2: Fixed missing semi-colon in macro.
      Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Acked-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Acked-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      8f082018
  24. 30 Apr, 2010 1 commit
  25. 04 Apr, 2010 1 commit
    • Frederic Weisbecker's avatar
      perf: Fetch hot regs from the template caller · 6cc8a7c1
      Frederic Weisbecker authored
      
      
      Trace events can be defined from a template using
      DECLARE_EVENT_CLASS/DEFINE_EVENT or directly with TRACE_EVENT.
      
      In both cases we have a template tracepoint handler, used to
      record the trace, to which we pass our ftrace event instance.
      
      In the function level, if the class is named "foo" and the event
      is named "blah", we have the following chain of calls:
      
      perf_trace_blah() -> perf_trace_templ_foo()
      
      In the case we have several events sharing the class "blah",
      we'll have multiple users of perf_trace_templ_foo(), and it
      won't be inlined by the compiler. This is usually what happens
      with the DECLARE_EVENT_CLASS/DEFINE_EVENT based definition.
      
      But if perf_trace_blah() is the only caller of perf_trace_templ_foo()
      there are fair chances that it will be inlined.
      
      The problem is that we fetch the regs from perf_trace_templ_foo()
      after we rewinded the frame pointer to the second caller, we want
      to reach the caller of perf_trace_blah() to get the right source
      of the event. And we do this by always assuming that
      perf_trace_templ_foo() is not inlined. But as shown above this
      is not always true. And if it is inlined we miss the first caller,
      losing the most important level of precision.
      
      We get:
      	    61.31%       ls  [kernel.kallsyms]  [k] do_softirq
                               |
                               --- do_softirq
                                   irq_exit
                                   do_IRQ
                                   common_interrupt
                                  |
                                  |--25.00%-- tty_buffer_request_room
      
      Instead of:
      	    61.31%       ls  [kernel.kallsyms]  [k] __do_softirq
                               |
                               --- __do_softirq
                                   do_softirq
                                   irq_exit
                                   do_IRQ
                                   common_interrupt
                                  |
                                  |--25.00%-- tty_buffer_request_room
      
      To fix this, we fetch the regs from perf_trace_blah() rather than
      perf_trace_templ_foo() so that we don't have to deal with inlining
      surprises.
      
      That also bring us the advantage of having the true source of the
      event even if we don't have frame pointers.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      6cc8a7c1