From: Tom Zanussi <zanussi@kernel.org>
To: Bagas Sanjaya <bagasdotme@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Documentation <linux-doc@vger.kernel.org>,
Linux Kernel Tracing <linux-trace-kernel@vger.kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Jonathan Corbet <corbet@lwn.net>
Subject: Re: [PATCH 1/5] Documentation: trace: histogram: Fix histogram trigger subsection number order
Date: Mon, 15 Sep 2025 10:07:54 -0500 [thread overview]
Message-ID: <4e6c3e28fe014d7350203b333c235188cdbe3dd2.camel@kernel.org> (raw)
In-Reply-To: <20250911042527.22573-2-bagasdotme@gmail.com>
On Thu, 2025-09-11 at 11:25 +0700, Bagas Sanjaya wrote:
> Section numbering in subsections of "Histogram Trigger Command"
> sections
> is inconsistent in order. In particular, "'hist' trigger examples" is
> erroneously numbered as 6.2, which is a leftover from b8df4a3634e08a
> ("tracing: Move hist trigger Documentation to histogram.txt").
>
> Fix the order.
Looks good to me, thanks!
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
>
> Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
> ---
> Documentation/trace/histogram.rst | 34 +++++++++++++++--------------
> --
> 1 file changed, 17 insertions(+), 17 deletions(-)
>
> diff --git a/Documentation/trace/histogram.rst
> b/Documentation/trace/histogram.rst
> index af6d2e15568ebd..d158dadaa42447 100644
> --- a/Documentation/trace/histogram.rst
> +++ b/Documentation/trace/histogram.rst
> @@ -186,8 +186,8 @@ Documentation written by Tom Zanussi
> The examples below provide a more concrete illustration of the
> concepts and typical usage patterns discussed above.
>
> -'special' event fields
> -------------------------
> +2.1. 'special' event fields
> +---------------------------
>
> There are a number of 'special event fields' available for use as
> keys or values in a hist trigger. These look like and behave as
> if
> @@ -204,16 +204,16 @@ Documentation written by Tom Zanussi
> common_cpu int the cpu on which the event occurred.
> ====================== ====
> =======================================
>
> -Extended error information
> ---------------------------
> +2.2. Extended error information
> +-------------------------------
>
> For some error conditions encountered when invoking a hist trigger
> command, extended error information is available via the
> tracing/error_log file. See Error Conditions in
> :file:`Documentation/trace/ftrace.rst` for details.
>
> -6.2 'hist' trigger examples
> ----------------------------
> +2.3. 'hist' trigger examples
> +----------------------------
>
> The first set of examples creates aggregations using the kmalloc
> event. The fields that can be used for the hist trigger are
> listed
> @@ -1608,8 +1608,8 @@ Extended error information
> Entries: 7
> Dropped: 0
>
> -2.2 Inter-event hist triggers
> ------------------------------
> +2.4. Inter-event hist triggers
> +------------------------------
>
> Inter-event hist triggers are hist triggers that combine values from
> one or more other events and create a histogram using that data.
> Data
> @@ -1685,8 +1685,8 @@ pseudo-file.
>
> These features are described in more detail in the following
> sections.
>
> -2.2.1 Histogram Variables
> --------------------------
> +2.5. Histogram Variables
> +------------------------
>
> Variables are simply named locations used for saving and retrieving
> values between matching events. A 'matching' event is defined as an
> @@ -1789,8 +1789,8 @@ or assigned to a variable and referenced in a
> subsequent expression::
>
> Variables can even hold stacktraces, which are useful with synthetic
> events.
>
> -2.2.2 Synthetic Events
> -----------------------
> +2.6. Synthetic Events
> +---------------------
>
> Synthetic events are user-defined events generated from hist trigger
> variables or fields associated with one or more other events. Their
> @@ -1846,7 +1846,7 @@ the command that defined it with a '!'::
> At this point, there isn't yet an actual 'wakeup_latency' event
> instantiated in the event subsystem - for this to happen, a 'hist
> trigger action' needs to be instantiated and bound to actual fields
> -and variables defined on other events (see Section 2.2.3 below on
> +and variables defined on other events (see Section 2.7. below on
> how that is done using hist trigger 'onmatch' action). Once that is
> done, the 'wakeup_latency' synthetic event instance is created.
>
> @@ -2094,8 +2094,8 @@ histogram::
> Entries: 7
> Dropped: 0
>
> -2.2.3 Hist trigger 'handlers' and 'actions'
> --------------------------------------------
> +2.7. Hist trigger 'handlers' and 'actions'
> +------------------------------------------
>
> A hist trigger 'action' is a function that's executed (in most cases
> conditionally) whenever a histogram entry is added or updated.
> @@ -2526,8 +2526,8 @@ The following commonly-used handler.action
> pairs are available:
> kworker/3:2-135 [003] d..3 49.823123: sched_switch:
> prev_comm=kworker/3:2 prev_pid=135 prev_prio=120 prev_state=T ==>
> next_comm=swapper/3 next_pid=0 next_prio=120
> <idle>-0 [004] ..s7 49.823798: tcp_probe:
> src=10.0.0.10:54326 dest=23.215.104.193:80 mark=0x0 length=32
> snd_nxt=0xe3ae2ff5 snd_una=0xe3ae2ecd snd_cwnd=10 ssthresh=2147483647
> snd_wnd=28960 srtt=19604 rcv_wnd=29312
>
> -3. User space creating a trigger
> ---------------------------------
> +2.8. User space creating a trigger
> +----------------------------------
>
> Writing into /sys/kernel/tracing/trace_marker writes into the ftrace
> ring buffer. This can also act like an event, by writing into the
> trigger
next prev parent reply other threads:[~2025-09-15 15:07 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-11 4:25 [PATCH 0/5] histogram docs formatting cleanup Bagas Sanjaya
2025-09-11 4:25 ` [PATCH 1/5] Documentation: trace: histogram: Fix histogram trigger subsection number order Bagas Sanjaya
2025-09-12 0:59 ` Masami Hiramatsu
2025-09-15 15:07 ` Tom Zanussi [this message]
2025-09-11 4:25 ` [PATCH 2/5] Documentation: trace: histogram-design: Trim trailing vertices in diagram explanation text Bagas Sanjaya
2025-09-12 1:01 ` Masami Hiramatsu
2025-09-15 15:09 ` Tom Zanussi
2025-09-11 4:25 ` [PATCH 3/5] Documentation: trace: historgram-design: Separate sched_waking histogram section heading and the following diagram Bagas Sanjaya
2025-09-12 1:03 ` Masami Hiramatsu
2025-09-15 15:10 ` Tom Zanussi
2025-09-11 4:25 ` [PATCH 4/5] Documentation: trace: histogram-design: Wrap introductory note in note:: directive Bagas Sanjaya
2025-09-12 1:03 ` Masami Hiramatsu
2025-09-15 15:11 ` Tom Zanussi
2025-09-11 4:25 ` [PATCH 5/5] Documentation: trace: histogram: Link to ftrace docs Bagas Sanjaya
2025-09-12 0:58 ` Masami Hiramatsu
2025-09-12 2:55 ` Bagas Sanjaya
2025-09-15 15:11 ` Tom Zanussi
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