Re: [PATCH 0/2][GIT PULL] tracing/filters: adjustements for strings

[Tom Zanussi <tzanussi@gmail.com>]

Hi,

On Mon, 2009-05-04 at 09:42 -0400, Steven Rostedt wrote:
> 
> On Sun, 3 May 2009, Frederic Weisbecker wrote:
> 
> > Hi,
> > 
> > The following patchset includes two little peas of features
> > for tracing filters, making them able to filter every kind of strings.
> > 
> > Now I can do this:
> > 
> > cd /debug/tracing
> > echo > trace
> > echo stacktrace > trace_options
> > 
> > cd events/lockdep
> > echo 'name == "&REISERFS_SB(s)->lock" && wait_usec > 0' > lock_acquired/filter
> > 
> > echo 1 > lock_acquired/enable
> > sleep 1
> > echo 0 > lock_acquired/enable
> > 
> > cat trace
> > 
> >  # tracer: nop
> >  #
> >  #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
> >  #              | |       |          |         |
> >            <...>-6464  [000]   327.448232: lock_acquired: &REISERFS_SB(s)->lock (25058.984 us)
> >            <...>-6464  [000]   327.448233: 
> >  <= reiserfs_get_block
> >  <= __block_prepare_write
> >  <= block_write_begin
> >  <= reiserfs_write_begin
> >  <= generic_file_buffered_write
> >  <= __generic_file_aio_write_nolock
> >  <= generic_file_aio_write
> >            <...>-6470  [000]   327.448422: lock_acquired: &REISERFS_SB(s)->lock (25112.702 us)
> >            <...>-6470  [000]   327.448425: 
> >  <= reiserfs_update_sd_size
> >  <= reiserfs_write_end
> >  <= generic_file_buffered_write
> >  <= __generic_file_aio_write_nolock
> >  <= generic_file_aio_write
> >  <= do_sync_write
> >  <= reiserfs_file_write
> > 
> > 
> > Tom, your filter framework is awesome and very useful!
> > Thanks :-)
> 
> I totally agree, and also like Frederic's changes.
> 
> But...
> 
> 
> This is all useless unless people know it exists and more importantly, how 
> to use it.
> 
> Ted Tso already started a Documentation/trace/events.txt. We need to add 
> documentation of this feature either in Doc../trace/events.txt or add a 
> new file called Doc../trace/filters.txt.  Probably would be better to add 
> a separate file, and add a "See filters.txt" in events.txt.
> 
> Tom or Frederic, could either of you write something up? I could when I 
> have time. The git logs seems to be pretty good at explaining it.
> 

Sure, I'll write something up and put it in Doc../trace/filters.txt.

Tom

> Thanks,
> 
> -- Steve
>