01 Nov, 2011

1 commit


08 Jan, 2011

1 commit

  • While doing some developing, Peter Zijlstra and I have found
    that if a CREATE_TRACE_POINTS include is done before module.h
    is included, it can break the build.

    We have been lucky so far that this has not broke the build
    since module.h is included in almost everything.

    Reported-by: Peter Zijlstra
    Signed-off-by: Steven Rostedt

    Steven Rostedt
     

03 Dec, 2010

1 commit

  • There are instances in the kernel that we only want to trace
    a tracepoint when a certain condition is set. But we do not
    want to test for that condition in the core kernel.
    If we test for that condition before calling the tracepoin, then
    we will be performing that test even when tracing is not enabled.
    This is 99.99% of the time.

    We currently can just filter out on that condition, but that happens
    after we write to the trace buffer. We just wasted time writing to
    the ring buffer for an event we never cared about.

    This patch adds:

    TRACE_EVENT_CONDITION() and DEFINE_EVENT_CONDITION()

    These have a new TP_CONDITION() argument that comes right after
    the TP_ARGS(). This condition can use the parameters of TP_ARGS()
    in the TRACE_EVENT() to determine if the tracepoint should be traced
    or not. The TP_CONDITION() will be placed in a if (cond) trace;

    For example, for the tracepoint sched_wakeup, it is useless to
    trace a wakeup event where the caller never actually wakes
    anything up (where success == 0). So adding:

    TP_CONDITION(success),

    which uses the "success" parameter of the wakeup tracepoint
    will have it only trace when we have successfully woken up a
    task.

    Acked-by: Mathieu Desnoyers
    Acked-by: Frederic Weisbecker
    Cc: Arjan van de Ven
    Cc: Thomas Gleixner
    Signed-off-by: Steven Rostedt

    Steven Rostedt
     

05 May, 2010

1 commit

  • When more than one header is included under CREATE_TRACE_POINTS
    the DECLARE_TRACE() macro is not defined back to its original meaning
    and the second include will fail to initialize the TRACE_EVENT()
    and DECLARE_TRACE() correctly.

    To fix this the tracepoint.h file moves the define of DECLARE_TRACE()
    out of the #ifdef _LINUX_TRACEPOINT_H protection (just like the
    define of the TRACE_EVENT()). This way the define_trace.h will undef
    the DECLARE_TRACE() at the end and allow new headers to start
    from scratch.

    This patch also requires fixing the include/events/napi.h

    It currently uses DECLARE_TRACE() and should be converted to a TRACE_EVENT()
    format. But I'll leave that change to the authors of that file.
    But since the napi.h file depends on using the CREATE_TRACE_POINTS
    and does not define its own DEFINE_TRACE() it must use the define_trace.h
    method instead.

    Cc: Neil Horman
    Cc: David S. Miller
    Cc: Mathieu Desnoyers
    Signed-off-by: Steven Rostedt

    Steven Rostedt
     

26 Nov, 2009

1 commit

  • It is not quite obvious at first sight what TRACE_EVENT_TEMPLATE
    does: does it define an event as well beyond defining a template?

    To clarify this, rename it to DECLARE_EVENT_CLASS, which follows
    the various 'DECLARE_*()' idioms we already have in the kernel:

    DECLARE_EVENT_CLASS(class)

    DEFINE_EVENT(class, event1)
    DEFINE_EVENT(class, event2)
    DEFINE_EVENT(class, event3)

    To complete this logic we should also rename TRACE_EVENT() to:

    DEFINE_SINGLE_EVENT(single_event)

    ... but in a more quiet moment of the kernel cycle.

    Cc: Pekka Enberg
    Cc: Steven Rostedt
    Cc: Frederic Weisbecker
    LKML-Reference:
    Signed-off-by: Ingo Molnar

    Ingo Molnar
     

25 Nov, 2009

2 commits

  • After creating the TRACE_EVENT_TEMPLATE I started to look at other
    trace points to see what duplication was made. I noticed that there
    are several trace points where they are almost identical except for
    the name and the output format. Since TRACE_EVENT_TEMPLATE was successful
    in bringing down the size of trace events, I added a DEFINE_EVENT_PRINT.

    DEFINE_EVENT_PRINT is used just like DEFINE_EVENT is. That is, the
    DEFINE_EVENT_PRINT also uses a TRACE_EVENT_TEMPLATE, but it allows the
    developer to overwrite the print format. If there are two or more
    TRACE_EVENTS that are identical except for the name and print, then
    they can be converted to use a TRACE_EVENT_TEMPLATE. Since the
    TRACE_EVENT_TEMPLATE already does the print output, the first trace event
    would have its print format held in the TRACE_EVENT_TEMPLATE and
    be defined with a DEFINE_EVENT. The rest will use the DEFINE_EVENT_PRINT
    and override the print format.

    Converting the sched trace points to both DEFINE_EVENT and
    DEFINE_EVENT_PRINT. Five were converted to DEFINE_EVENT and two were
    converted to DEFINE_EVENT_PRINT.

    I was able to get the following:

    $ size kernel/sched.o-*
    text data bss dec hex filename
    79299 6776 2520 88595 15a13 kernel/sched.o-notrace
    101941 11896 2584 116421 1c6c5 kernel/sched.o-templ
    104779 11896 2584 119259 1d1db kernel/sched.o-trace

    sched.o-notrace is the scheduler compiled with no trace points.
    sched.o-templ is with the use of DEFINE_EVENT and DEFINE_EVENT_PRINT
    sched.o-trace is the current trace events.

    Signed-off-by: Steven Rostedt

    Steven Rostedt
     
  • There are some places in the kernel that define several tracepoints and
    they are all identical besides the name. The code to enable, disable and
    record is created for every trace point even if most of the code is
    identical.

    This patch adds TRACE_EVENT_TEMPLATE that lets the developer create
    a template TRACE_EVENT and create trace points with DEFINE_EVENT, which
    is based off of a given template. Each trace point used by this
    will share most of the code, and bring down the size of the kernel
    when there are several duplicate events.

    Usage is:

    TRACE_EVENT_TEMPLATE(name, proto, args, tstruct, assign, print);

    Which would be the same as defining a normal TRACE_EVENT.

    To create the trace events that the trace points will use:

    DEFINE_EVENT(template, name, proto, args) is done. The template
    is the name of the TRACE_EVENT_TEMPLATE to use. The name is the
    name of the trace point. The parameters proto and args must be the same
    as the proto and args of the template. If they are not the same,
    then a compile error will result. I tried hard removing this duplication
    but the C preprocessor is not powerful enough (or my CPP magic
    experience points is not at a high enough level) to not need them.

    A lot of trace events are coming in with new XFS development. Most of
    the trace points are identical except for the name. The following shows
    the advantage of having TRACE_EVENT_TEMPLATE:

    $ size fs/xfs/xfs.o.*
    text data bss dec hex filename
    452114 2788 3520 458422 6feb6 fs/xfs/xfs.o.old
    638482 38116 3744 680342 a6196 fs/xfs/xfs.o.template
    996954 38116 4480 1039550 fdcbe fs/xfs/xfs.o.trace

    xfs.o.old is without any tracepoints.
    xfs.o.template uses the new TRACE_EVENT_TEMPLATE.
    xfs.o.trace uses the current TRACE_EVENT macros.

    Requested-by: Christoph Hellwig
    Signed-off-by: Steven Rostedt

    Steven Rostedt
     

28 Aug, 2009

1 commit

  • The recent commit:

    tracing/events: fix the include file dependencies

    fixed a file dependency problem while including more than
    one trace event header file.

    This fix undefined TRACE_EVENT after an event header macro
    preprocessing in order to make tracepoint.h able to correctly declare
    the tracepoints necessary for the next event header file.

    But now we also need to undefine TRACE_EVENT_FN at the end of an event
    header file preprocessing for the same reason.

    This fixes the following build error:

    In file included from include/trace/events/napi.h:5,
    from net/core/net-traces.c:28:
    include/linux/tracepoint.h:285:1: warning: "TRACE_EVENT_FN" redefined
    In file included from include/trace/define_trace.h:61,
    from include/trace/events/skb.h:40,
    from net/core/net-traces.c:27:
    include/trace/ftrace.h:50:1: warning: this is the location of the previous definition
    In file included from include/trace/events/napi.h:5,
    from net/core/net-traces.c:28:
    include/linux/tracepoint.h:285:1: warning: "TRACE_EVENT_FN" redefined
    In file included from include/trace/define_trace.h:61,
    from include/trace/events/skb.h:40,
    from net/core/net-traces.c:27:
    include/trace/ftrace.h:50:1: warning: this is the location of the previous definition

    Reported-by: Ingo Molnar
    Signed-off-by: Frederic Weisbecker
    Cc: Masami Hiramatsu
    Cc: Xiao Guangrong
    Cc: Steven Rostedt
    Cc: Li Zefan
    LKML-Reference:
    Signed-off-by: Ingo Molnar

    Frederic Weisbecker
     

26 Aug, 2009

3 commits

  • …deric/random-tracing into tracing/core

    Conflicts:
    include/linux/tracepoint.h

    Signed-off-by: Ingo Molnar <mingo@elte.hu>

    Ingo Molnar
     
  • The TRACE_EVENT depends on the include/linux/tracepoint.h first
    and include/trace/ftrace.h later, if we include the ftrace.h early,
    a building error will occur.

    Both define TRACE_EVENT in trace_a.h and trace_b.h, if we include
    those in .c file, like this:

    #define CREATE_TRACE_POINTS
    include
    include

    The above will not work, because the TRACE_EVENT was re-defined by
    the previous .h file.

    Reported-by: Wei Yongjun
    Signed-off-by: Xiao Guangrong
    LKML-Reference:
    Signed-off-by: Steven Rostedt

    Xiao Guangrong
     
  • It's not strictly correct for the tracepoint reg/unreg callbacks to
    occur when a client is hooking up, because the actual tracepoint may not
    be present yet. This happens to be fine for syscall, since that's in
    the core kernel, but it would cause problems for tracepoints defined in
    a module that hasn't been loaded yet. It also means the reg/unreg has
    to be EXPORTed for any modules to use the tracepoint (as in SystemTap).

    This patch removes DECLARE_TRACE_WITH_CALLBACK, and instead introduces
    DEFINE_TRACE_FN which stores the callbacks in struct tracepoint. The
    callbacks are used now when the active state of the tracepoint changes
    in set_tracepoint & disable_tracepoint.

    This also introduces TRACE_EVENT_FN, so ftrace events can also provide
    registration callbacks if needed.

    Signed-off-by: Josh Stone
    Cc: Jason Baron
    Cc: Frederic Weisbecker
    Cc: Ingo Molnar
    Cc: Li Zefan
    Cc: Steven Rostedt
    Cc: Peter Zijlstra
    Cc: Mathieu Desnoyers
    Cc: Jiaying Zhang
    Cc: Martin Bligh
    Cc: Lai Jiangshan
    Cc: Paul Mundt
    Cc: Martin Schwidefsky
    Cc: Heiko Carstens
    LKML-Reference:
    Signed-off-by: Frederic Weisbecker

    Josh Stone
     

24 Apr, 2009

2 commits

  • The TRACE_FORMAT macro has been deprecated by the TRACE_EVENT macro.
    There are no more users. All new users must use the TRACE_EVENT macro.

    [ Impact: remove old functionality ]

    Cc: Peter Zijlstra
    Signed-off-by: Steven Rostedt

    Steven Rostedt
     
  • In case a module uses the TRACE_EVENT macro for creating automated
    events in ftrace, it may choose to use a different file name
    than the defined system name, or choose to use a different path than
    the default "include/trace/events" include path.

    If this is done, then before including trace/define_trace.h the
    header would define either "TRACE_INCLUDE_FILE" for the file
    name or "TRACE_INCLUDE_PATH" for the include path.

    If it does not define these, then the define_trace.h defines them
    instead. If define trace defines them, then define_trace.h should
    also undefine them before exiting. To do this a macro is used
    to note this:

    #ifndef TRACE_INCLUDE_FILE
    # define TRACE_INCLUDE_FILE TRACE_SYSTEM
    # define UNDEF_TRACE_INCLUDE_FILE
    #endif

    [...]

    #ifdef UNDEF_TRACE_INCLUDE_FILE
    # undef TRACE_INCLUDE_FILE
    # undef UNDEF_TRACE_INCLUDE_FILE
    #endif

    The UNDEF_TRACE_INCLUDE_FILE acts as a CPP variable to know to undef
    the TRACE_INCLUDE_FILE before leaving define_trace.h.

    Unfortunately, due to cut and paste errors, the macros between
    FILE and PATH got mixed up.

    [ Impact: undef TRACE_INCLUDE_FILE and/or TRACE_INCLUDE_PATH when needed ]

    Signed-off-by: Steven Rostedt

    Steven Rostedt
     

18 Apr, 2009

1 commit

  • The CONFIG_EVENT_TRACER is the way to turn on event tracing when no
    other tracing has been configured. All code to get enabled should
    depend on CONFIG_EVENT_TRACING. That is what is enabled when TRACING
    (or CONFIG_EVENT_TRACER) is selected.

    This patch enables the include/trace/ftrace.h file when
    CONFIG_EVENT_TRACING is enabled.

    [ Impact: fix warning in event tracer selftest ]

    Signed-off-by: Steven Rostedt

    Steven Rostedt
     

15 Apr, 2009

3 commits

  • Impact: clean up

    Create a sub directory in include/trace called events to keep the
    trace point headers in their own separate directory. Only headers that
    declare trace points should be defined in this directory.

    Cc: Peter Zijlstra
    Cc: Thomas Gleixner
    Cc: Neil Horman
    Cc: Zhao Lei
    Cc: Eduard - Gabriel Munteanu
    Cc: Pekka Enberg
    Signed-off-by: Steven Rostedt

    Steven Rostedt
     
  • This patch moves the ftrace creation into include/trace/ftrace.h and
    simplifies the work of developers in adding new tracepoints.
    Just the act of creating the trace points in include/trace and including
    define_trace.h will create the events in the debugfs/tracing/events
    directory.

    This patch removes the need of include/trace/trace_events.h

    Signed-off-by: Steven Rostedt

    Steven Rostedt
     
  • This patch lowers the number of places a developer must modify to add
    new tracepoints. The current method to add a new tracepoint
    into an existing system is to write the trace point macro in the
    trace header with one of the macros TRACE_EVENT, TRACE_FORMAT or
    DECLARE_TRACE, then they must add the same named item into the C file
    with the macro DEFINE_TRACE(name) and then add the trace point.

    This change cuts out the needing to add the DEFINE_TRACE(name).
    Every file that uses the tracepoint must still include the trace/.h
    file, but the one C file must also add a define before the including
    of that file.

    #define CREATE_TRACE_POINTS
    #include

    This will cause the trace/mytrace.h file to also produce the C code
    necessary to implement the trace point.

    Note, if more than one trace/.h is used to create the C code
    it is best to list them all together.

    #define CREATE_TRACE_POINTS
    #include
    #include
    #include

    Thanks to Mathieu Desnoyers and Christoph Hellwig for coming up with
    the cleaner solution of the define above the includes over my first
    design to have the C code include a "special" header.

    This patch converts sched, irq and lockdep and skb to use this new
    method.

    Cc: Peter Zijlstra
    Cc: Thomas Gleixner
    Cc: Neil Horman
    Cc: Zhao Lei
    Cc: Eduard - Gabriel Munteanu
    Cc: Pekka Enberg
    Signed-off-by: Steven Rostedt

    Steven Rostedt