From: Beau Belgrave <beaub@linux.microsoft.com>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: rostedt@goodmis.org, linux-trace-devel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 09/12] user_events: Add documentation file
Date: Mon, 3 Jan 2022 15:01:39 -0800 [thread overview]
Message-ID: <20220103230139.GA1522@kbox> (raw)
In-Reply-To: <20211222231834.875f662b37fe673dec0b3663@kernel.org>
On Wed, Dec 22, 2021 at 11:18:34PM +0900, Masami Hiramatsu wrote:
> Hi Beau,
>
> On Thu, 16 Dec 2021 09:35:08 -0800
> Beau Belgrave <beaub@linux.microsoft.com> wrote:
>
> > Add a documentation file about user_events with example code, etc.
> > explaining how it may be used.
> >
> > Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
> > ---
> > Documentation/trace/index.rst | 1 +
> > Documentation/trace/user_events.rst | 195 ++++++++++++++++++++++++++++
> > 2 files changed, 196 insertions(+)
> > create mode 100644 Documentation/trace/user_events.rst
> >
> > diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
> > index 3769b9b7aed8..3a47aa8341c6 100644
> > --- a/Documentation/trace/index.rst
> > +++ b/Documentation/trace/index.rst
> > @@ -30,3 +30,4 @@ Linux Tracing Technologies
> > stm
> > sys-t
> > coresight/index
> > + user_events
> > diff --git a/Documentation/trace/user_events.rst b/Documentation/trace/user_events.rst
> > new file mode 100644
> > index 000000000000..36104b537476
> > --- /dev/null
> > +++ b/Documentation/trace/user_events.rst
> > @@ -0,0 +1,195 @@
> > +=========================================
> > +user_events: User-based Event Tracing
> > +=========================================
[..]
> > +Registering
> > +-----------
> > +Registering within a user process is done via ioctl() out to the
> > +/sys/kernel/debug/tracing/user_events_data file. The command to issue is
> > +DIAG_IOCSREG. This command takes a struct user_reg as an argument.
> > +
>
> Could you add the user_reg data structure here?
>
Sure thing.
> > +The struct user_reg requires two values, the first is the size of the structure
> > +to ensure forward and backward compatibility. The second is the command string
> > +to issue for registering.
>
> This explanation may be a bit out of date?
> user_reg has 4 fields. 2 for input, 2 for output.
>
Yeah, it only requires 2 inputs to work. I'll try to make this clearer.
> And could you add a section for DIAG_IOCSDEL?
>
Sure thing.
> > +
> > +User based events show up under tracefs like any other event under the
> > +subsystem named "user_events". This means tools that wish to attach to the
> > +events need to use /sys/kernel/debug/tracing/events/user_events/[name]/enable
> > +or perf record -e user_events:[name] when attaching/recording.
> > +
> > +**NOTE:** *The write_index returned is only valid for the FD that was used*
> > +
[..]
> > +Example Code
> > +------------
> > +See sample code in samples/user_events.
>
> Maybe tools/testing/selftests/user_events ?
>
Previously I was asked to put the sample code in samples/user_events, so
it lives there.
Thanks,
-Beau
next prev parent reply other threads:[~2022-01-03 23:01 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-16 17:34 [PATCH v8 00/12] user_events: Enable user processes to create and write to trace events Beau Belgrave
2021-12-16 17:35 ` [PATCH v8 01/12] user_events: Add minimal support for trace_event into ftrace Beau Belgrave
2021-12-21 15:16 ` Masami Hiramatsu
2022-01-03 18:22 ` Beau Belgrave
2021-12-16 17:35 ` [PATCH v8 02/12] user_events: Add print_fmt generation support for basic types Beau Belgrave
2021-12-22 0:30 ` Masami Hiramatsu
2022-01-03 18:56 ` Beau Belgrave
2021-12-16 17:35 ` [PATCH v8 03/12] user_events: Handle matching arguments from dyn_events Beau Belgrave
2021-12-22 6:19 ` Masami Hiramatsu
2021-12-16 17:35 ` [PATCH v8 04/12] user_events: Add basic perf and eBPF support Beau Belgrave
2021-12-22 7:55 ` Masami Hiramatsu
2021-12-16 17:35 ` [PATCH v8 05/12] user_events: Add self-test for ftrace integration Beau Belgrave
2021-12-16 17:35 ` [PATCH v8 06/12] user_events: Add self-test for dynamic_events integration Beau Belgrave
2021-12-16 17:35 ` [PATCH v8 07/12] user_events: Add self-test for perf_event integration Beau Belgrave
2021-12-16 17:35 ` [PATCH v8 08/12] user_events: Optimize writing events by only copying data once Beau Belgrave
2021-12-22 15:11 ` Masami Hiramatsu
2022-01-03 18:58 ` Beau Belgrave
2022-01-06 22:17 ` Steven Rostedt
2022-01-06 23:05 ` Beau Belgrave
2021-12-16 17:35 ` [PATCH v8 09/12] user_events: Add documentation file Beau Belgrave
2021-12-22 14:18 ` Masami Hiramatsu
2022-01-03 23:01 ` Beau Belgrave [this message]
2022-01-06 21:14 ` Steven Rostedt
2021-12-16 17:35 ` [PATCH v8 10/12] user_events: Add sample code for typical usage Beau Belgrave
2021-12-22 23:18 ` Masami Hiramatsu
2022-01-06 22:09 ` Steven Rostedt
2022-01-06 23:06 ` Beau Belgrave
2021-12-16 17:35 ` [PATCH v8 11/12] user_events: Validate user payloads for size and null termination Beau Belgrave
2021-12-23 0:08 ` Masami Hiramatsu
2022-01-03 18:53 ` Beau Belgrave
2022-01-06 23:32 ` Masami Hiramatsu
2022-01-07 1:01 ` Beau Belgrave
2021-12-16 17:35 ` [PATCH v8 12/12] user_events: Add self-test for validator boundaries Beau Belgrave
2022-04-18 20:43 ` [PATCH v8 00/12] user_events: Enable user processes to create and write to trace events Hagen Paul Pfeifer
2022-04-19 0:25 ` Beau Belgrave
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