From: Bagas Sanjaya <bagasdotme@gmail.com>
To: 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>,
Tom Zanussi <zanussi@kernel.org>,
Bagas Sanjaya <bagasdotme@gmail.com>
Subject: [PATCH 1/5] Documentation: trace: histogram: Fix histogram trigger subsection number order
Date: Thu, 11 Sep 2025 11:25:23 +0700 [thread overview]
Message-ID: <20250911042527.22573-2-bagasdotme@gmail.com> (raw)
In-Reply-To: <20250911042527.22573-1-bagasdotme@gmail.com>
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.
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
--
An old man doll... just what I always wanted! - Clara
next prev parent reply other threads:[~2025-09-11 4:25 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 ` Bagas Sanjaya [this message]
2025-09-12 0:59 ` [PATCH 1/5] Documentation: trace: histogram: Fix histogram trigger subsection number order Masami Hiramatsu
2025-09-15 15:07 ` Tom Zanussi
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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