lkml.org 
[lkml]   [2009]   [Jan]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 0/2] ftrace: updates to tip
    2009/1/16 Ingo Molnar <mingo@elte.hu>:
    >
    > * Steven Rostedt <rostedt@goodmis.org> wrote:
    >
    >> Ingo,
    >>
    >> The first patch is critical, and needs to stay with trace_output.c Not
    >> that critical since trace_output.c is not in mainline yet.
    >>
    >> The second patch gives the ability to stack trace functions. I've been
    >> leery about adding this and still keep it a separate option from the
    >> "stacktrace" that already exists. This is because when enabled with no
    >> filtering, the lag between typing and seeing what is typed can be up to
    >> 10 seconds or more.
    >
    > Btw., is this true even if frame pointers are enabled? When frame pointers
    > are disabled we scan the full kernel stack => that can be quite slow if
    > every kernel function is traced ;-)


    Hi Ingo,

    The function tracer selects Frame pointers :-)

    Frederic.


    >> I made the function stack trace an option attached to the function
    >> tracer, so it must be enabled after the function tracer has been set.
    >> This still needs to be updated in ftrace.txt.
    >
    > maybe we could drive this via the filter API? Something like:
    >
    > echo "*btrfs*:stacktrace" >> set_filter_functions
    >
    > Would automatically mean that those functions will all generate
    > stacktraces too. Note how safe this API is by default: the filter is used
    > for a narrow scope of functions anwyay. To get it for all kernel functions
    > one would have to do:
    >
    > echo "*:stacktrace" >> set_filter_functions
    >
    > Which one cannot do accidentally.
    >
    > What do you think?
    >
    >> The following patches are in:
    >>
    >> git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
    >>
    >> branch: tip/devel
    >>
    >>
    >> Lai Jiangshan (1):
    >> ftrace: fix trace_output
    >>
    >> Steven Rostedt (1):
    >> ftrace: add stack trace to function tracer
    >>
    >> ----
    >> kernel/trace/trace.c | 26 ++++++++----
    >> kernel/trace/trace.h | 7 +++
    >> kernel/trace/trace_functions.c | 84 ++++++++++++++++++++++++++++++++++++++++
    >> kernel/trace/trace_output.c | 65 +++++++++++++++----------------
    >> kernel/trace/trace_output.h | 4 +-
    >> 5 files changed, 141 insertions(+), 45 deletions(-)
    >
    > Pulled into tip/tracing/ftrace, thanks Steve!
    >
    > Ingo
    >


    \
     
     \ /
      Last update: 2009-01-16 14:11    [W:4.084 / U:0.652 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site