Re: [PATCH 00/15] [git pull] for tip/tracing/ftrace

[Frederic Weisbecker <fweisbec@gmail.com>]

On Tue, Feb 17, 2009 at 12:12:27AM -0500, Steven Rostedt wrote:
> 
> Ingo,
> 
> This is a patch series that offers a variety of features.
> 
> The first is to add:
> 
>  #### all functions enabled ####
> 
> to set_ftrace_filter when all functions will be traced when function
> tracing is on.
> 
> The next is to add a :command: interface, and the module command:
> 
>  echo '*:mod:ext4' > set_ftrace_filter
> 
> Will select all functions in the ext4 module.
> 
>  echo '!*write*:mod:ext4' > set_ftrace_filter
> 
> will remove all functions with the characters 'write' and are
> in ext4.
> 
> Next we extend the :command: interface as well as add a way to
> hook tracers to specific functions. Instead of tracing all functions
> the same, this patch series adds a hash to be able to trace different
> functions differently.
> 
> I implement a 'traceon' and 'traceoff' to have a function start or
> stop tracing when it is hit. It also includes a counter for the
> number of times to implement the trace on/off.
> 
>  echo '*_lock:traceon:4' > set_ftrace_filter
>  echo '*_unlock:traceoff:5' > set_ftrace_filter

That's great!
I guess it could be useful to be able to pass it as a kernel parameter.
Something like that ftrace=function_tracer ftrace_filter='*_lock:traceon:4'


> This will have all functions that end with _lock turn on tracing
> and all that end with _unlock disable it, 4 times each.
> 
> The following patches are in:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
> 
>     branch: tip/tracing/ftrace
> 
> 
> Steven Rostedt (15):
>       ftrace: state that all functions are enabled in set_ftrace_filter
>       ftrace: add do_for_each_ftrace_rec and while_for_each_ftrace_rec
>       ftrace: rename ftrace_match to ftrace_match_records
>       ftrace: break up ftrace_match_records into smaller components
>       ftrace: add module command function filter selection
>       ftrace: enable filtering only when a function is filtered on
>       ftrace: add command interface for function selection
>       ftrace: convert ftrace_lock from a spinlock to mutex
>       ftrace: consolidate mutexes
>       ftrace: trace different functions with a different tracer
>       ring-buffer: add tracing_is_on to test if ring buffer is enabled
>       ftrace: add traceon traceoff commands to enable/disable the buffers
>       ftrace: show selected functions in set_ftrace_filter
>       ftrace: add pretty print to selected fuction traces
>       ftrace: add pretty print function for traceon and traceoff hooks
> 
> ----
>  include/linux/ftrace.h         |   40 ++
>  include/linux/ring_buffer.h    |    2 +
>  kernel/trace/ftrace.c          |  929 +++++++++++++++++++++++++++++++---------
>  kernel/trace/ring_buffer.c     |    9 +
>  kernel/trace/trace_functions.c |  163 +++++++
>  5 files changed, 946 insertions(+), 197 deletions(-)
> --