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From: Tomas Glozar <tglozar@redhat.com>
To: Steven Rostedt <rostedt@goodmis.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Jonathan Corbet <corbet@lwn.net>
Cc: linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	John Kacur <jkacur@redhat.com>,
	Luis Goncalves <lgoncalv@redhat.com>,
	Costa Shulyupin <costa.shul@redhat.com>,
	Crystal Wood <crwood@redhat.com>,
	Attila Fazekas <afazekas@redhat.com>,
	Tomas Glozar <tglozar@redhat.com>
Subject: [PATCH 8/9] Documentation/trace: Specify exact priority for timerlat
Date: Fri, 10 Oct 2025 10:33:37 +0200	[thread overview]
Message-ID: <20251010083338.478961-9-tglozar@redhat.com> (raw)
In-Reply-To: <20251010083338.478961-1-tglozar@redhat.com>

The timerlat tracer documentation mentions that threads are created with
real-time priority, but does not mention which priority and scheduling
class is used.

Add the information so that users do not have to look it up in
trace_osnoise.c.

Signed-off-by: Tomas Glozar <tglozar@redhat.com>
---
 Documentation/trace/timerlat-tracer.rst | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/Documentation/trace/timerlat-tracer.rst b/Documentation/trace/timerlat-tracer.rst
index 53a56823e903..68d429d454a5 100644
--- a/Documentation/trace/timerlat-tracer.rst
+++ b/Documentation/trace/timerlat-tracer.rst
@@ -43,12 +43,12 @@ It is possible to follow the trace by reading the trace file::
            <...>-868     [001] ....    54.030347: #2     context thread timer_latency      4351 ns
 
 
-The tracer creates a per-cpu kernel thread with real-time priority that
-prints two lines at every activation. The first is the *timer latency*
-observed at the *hardirq* context before the activation of the thread.
-The second is the *timer latency* observed by the thread. The ACTIVATION
-ID field serves to relate the *irq* execution to its respective *thread*
-execution.
+The tracer creates a per-cpu kernel thread with real-time priority
+SCHED_FIFO:95 that prints two lines at every activation. The first is
+the *timer latency* observed at the *hardirq* context before the activation
+of the thread. The second is the *timer latency* observed by the thread.
+The ACTIVATION ID field serves to relate the *irq* execution to its
+respective *thread* execution.
 
 The *irq*/*thread* splitting is important to clarify in which context
 the unexpected high value is coming from. The *irq* context can be
-- 
2.51.0


  parent reply	other threads:[~2025-10-10  8:34 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-10  8:33 [PATCH 0/9] Documentation/rtla: Cover default options Tomas Glozar
2025-10-10  8:33 ` [PATCH 1/9] Documentation/rtla: Fix typo in common_options.txt Tomas Glozar
2025-10-10  8:33 ` [PATCH 2/9] Documentation/rtla: Fix typo in common_timerlat_options.txt Tomas Glozar
2025-10-10  8:33 ` [PATCH 3/9] Documentation/rtla: Fix typo in rtla-timerlat-top.rst Tomas Glozar
2025-10-10  8:33 ` [PATCH 4/9] Documentation/rtla: Fix typo in common_timerlat_options.txt Tomas Glozar
2025-10-10  8:33 ` [PATCH 5/9] Documentation/rtla: Correct tracer name for common options Tomas Glozar
2025-10-10  8:33 ` [PATCH 6/9] Documentation/rtla: Mention default priority Tomas Glozar
2025-10-10  8:33 ` [PATCH 7/9] Documentation/rtla: Mention default cgroup state Tomas Glozar
2025-10-10  8:33 ` Tomas Glozar [this message]
2025-10-10  8:33 ` [PATCH 9/9] Documentation/rtla: Include defaults for tracer options Tomas Glozar
2025-11-03 23:35 ` [PATCH 0/9] Documentation/rtla: Cover default options Jonathan Corbet
2025-11-04  0:22   ` Steven Rostedt
2025-11-05 18:19     ` Jonathan Corbet
2025-11-04  0:32   ` Bagas Sanjaya

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