lkml.org 
[lkml]   [2020]   [Jan]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v3 00/12] tracing: Add support for in-kernel dynamic event API
From
Date
Hi Masami,

On Mon, 2020-01-27 at 22:48 +0900, Masami Hiramatsu wrote:
> Hi Tom,
>
> On Fri, 24 Jan 2020 16:56:11 -0600
> Tom Zanussi <zanussi@kernel.org> wrote:
>
> > Hi,
> >
> > This is v3 of 'tracing: Add support for in-kernel dynamic event
> > API',
> > incorporating changes based on suggestions from Masami and Steven.
> >
> > - Rebased to trace/for-next
> >
> > - Regularized the entire API to use synth_event_*,
> > kprobe_event_*,
> > dynevent_*, and added some new macros and functions to make
> > things
> > more consistent
> >
> > - Introduced trace_array_find_get() and used it in
> > trace_array_get_file() as suggested
> >
> > - Removed exports from dynevent_cmd functions that didn't need to
> > be
> > exported
> >
> > - Switched the param order of __kprobe_event_gen_cmd_start() to
> > fix
> > a problem found building with clang. Apparently varargs and
> > implicit promotion of types like bool don't mix. Thanks to
> > Nick
> > Desaulniers for pointing that out.
> >
> > - Updated the documentation for all of the above
> >
> > Text from the v2 posting:
> >
> > This is v2 of the previous 'tracing: Add support for in-kernel
> > synthetic event API', and is largely a rewrite based on suggestions
> > from Masami to expand the scope to include other types of dynamic
> > events such as kprobe events, in addition to the original sythetic
> > event focus.
>
> Yeah, v3 basically looks good to me now :)
> Please see my comment on [4/12]. Others are good. You can put my
> Acked-by to those patches.
>
> Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
> except for [04/12].
>
> Thank you!
>

OK, I'll add your acks for those.

Thanks for all your comments!

Tom

> >
> > The functionality of the original API remains available, though
> > it's
> > in a slightly different form due to the use of the new dynevent_cmd
> > API it's now based on. The dynevent_cmd API provides a common
> > dynamic
> > event command generation capability that both the synthetic event
> > API
> > and the kprobe event API are now based on, and there are now test
> > modules demonstrating both the synthetic event and kprobes APIs.
> >
> > A couple of the patches are snippets from Masami's 'tracing:
> > bootconfig: Boot-time tracing and Extra boot config' series, and
> > the
> > patch implementing the dynevent_cmd API includes some of the
> > spnprintf() generating code from that patchset.
> >
> > Because I used Masami's gen_*_cmd() naming suggestion for
> > generating
> > the commands, the previous patchset's generate_*() functions were
> > renamed to trace_*() to avoid confusion, and probably is better
> > naming
> > anyway.
> >
> > An overview of the user-visible changes in comparison to v1:
> >
> > - create_synth_event() using an array of synth_desc_fields
> > remains
> > unchanged and works the same way as previously
> >
> > - gen_synth_cmd() takes a variable-length number of args which
> > represent 'type field;' pairs. Using this with no field args
> > basically replaces the previous 'create_empty_synth_event()'
> >
> > - The 'add_synth_field()' and 'add_synth_fields()' function from
> > v1
> > are essentially the same except that they now take a
> > dynevent_cmd
> > instead of a synth_event pointer
> >
> > - The finalize_synth_event() from v1 is replaced by
> > create_dynevent() in the new version.
> >
> > - The new v2 API includes some additional functions to initialize
> > the dynevent_cmd - synth_dynevent_cmd() is used to do
> > that. While
> > it's an extra step, it makes it easier to do error handling.
> >
> > - There's a new trace_synth_event() function that traces a
> > synthetic
> > event using a variable-arg list of values.
> >
> > - The original generate_synth_event() using an array of values is
> > now called trace_synth_event_array().
> >
> > - For piecewise event tracing, the original
> > generate_synth_event_start() and generate_synth_event_end()
> > have
> > now been renamed to trace_synth_event_end().
> >
> > - add_next_synth_val() and add_synth_val() remain the same.
> >
> > - A similar API and test module demonstrating the API has been
> > added
> > for kprobe events
> >
> > - Both the synthetic events and kprobe events API is based on the
> > dynevent_cmd API, newly added
> >
> > - The Documentation for all of the above has been updated
> >
> > Text from the orginal v1 posting:
> >
> > I've recently had several requests and suggestions from users to
> > add
> > support for the creation and generation of synthetic events from
> > kernel code such as modules, and not just from the available
> > command
> > line commands.
> >
> > This patchset adds support for that. The first three patches add
> > some
> > minor preliminary setup, followed by the two main patches that add
> > the
> > ability to create and generate synthetic events from the
> > kernel. The
> > next patch adds a test module that demonstrates actual use of the
> > API
> > and verifies that it works as intended, followed by Documentation.
> >
> > Special thanks to Artem Bityutskiy, who worked with me over several
> > iterations of the API, and who had many great suggestions on the
> > details of the interface, and pointed out several problems with the
> > code itself.
> >
> > The following changes since commit
> > 659ded30272d67a04b3692f0bfa12263be20d790:
> >
> > trace/kprobe: Remove unused MAX_KPROBE_CMDLINE_SIZE (2020-01-22
> > 07:07:38 -0500)
> >
> > are available in the git repository at:
> >
> > git://git.kernel.org/pub/scm/linux/kernel/git/zanussi/linux-
> > trace.git ftrace/synth-event-gen-v3
> >
> > Tom Zanussi (12):
> > tracing: Add trace_array_find/_get() to find instance trace
> > arrays
> > tracing: Add trace_get/put_event_file()
> > tracing: Add synth_event_delete()
> > tracing: Add dynamic event command creation interface
> > tracing: Add synthetic event command generation functions
> > tracing: Change trace_boot to use synth_event interface
> > tracing: Add synth_event_trace() and related functions
> > tracing: Add synth event generation test module
> > tracing: Add kprobe event command generation functions
> > tracing: Change trace_boot to use kprobe_event interface
> > tracing: Add kprobe event command generation test module
> > tracing: Documentation for in-kernel synthetic event API
> >
> > Documentation/trace/events.rst | 515 ++++++++++++++++++++
> > include/linux/trace_events.h | 124 +++++
> > kernel/trace/Kconfig | 25 +
> > kernel/trace/Makefile | 2 +
> > kernel/trace/kprobe_event_gen_test.c | 225 +++++++++
> > kernel/trace/synth_event_gen_test.c | 523 ++++++++++++++++++++
> > kernel/trace/trace.c | 43 +-
> > kernel/trace/trace.h | 36 ++
> > kernel/trace/trace_boot.c | 66 ++-
> > kernel/trace/trace_events.c | 325 +++++++++++++
> > kernel/trace/trace_events_hist.c | 896
> > ++++++++++++++++++++++++++++++++++-
> > kernel/trace/trace_kprobe.c | 160 ++++++-
> > 12 files changed, 2868 insertions(+), 72 deletions(-)
> > create mode 100644 kernel/trace/kprobe_event_gen_test.c
> > create mode 100644 kernel/trace/synth_event_gen_test.c
> >
> > --
> > 2.14.1
> >
>
>

\
 
 \ /
  Last update: 2020-01-27 16:29    [W:0.090 / U:1.084 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site