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Fri, 06 Nov 2026 08:06:48 -0800 (PST) Received: from localhost.localdomain ([2a00:6d43:105:c401:e307:1a37:2e76:ce91]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4b57373f7f1sm172665795e9.15.2026.11.06.08.06.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 06 Nov 2026 08:06:47 -0800 (PST) From: Marco Crivellari To: linux-kernel@vger.kernel.org Cc: Frederic Weisbecker , "Paul E . McKenney" , Ingo Molnar , Marco Crivellari , Michal Hocko , Aaron Tomlin , Anna-Maria Behnsen , Thomas Gleixner , Jonathan Corbet , Shuah Khan , Randy Dunlap , linux-doc@vger.kernel.org Subject: [PATCH 3/3] Documentation: no_hz: Add tick stop in polling idle Date: Fri, 6 Nov 2026 17:06:15 +0100 Message-ID: <20261106160621.347228-4-marco.crivellari@suse.com> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261106160621.347228-1-marco.crivellari@suse.com> References: <20261106160621.347228-1-marco.crivellari@suse.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On nohz_full CPUs the scheduling-clock tick is stopped while polling. Update the documentation accordingly. Cc: Anna-Maria Behnsen Cc: Thomas Gleixner Cc: Jonathan Corbet Cc: Shuah Khan Cc: Randy Dunlap Cc: linux-doc@vger.kernel.org Signed-off-by: Marco Crivellari --- Documentation/timers/no_hz.rst | 3 +++ 1 file changed, 3 insertions(+) diff --git a/Documentation/timers/no_hz.rst b/Documentation/timers/no_hz.rst index 4006cab64079..d3ada4a0ebea 100644 --- a/Documentation/timers/no_hz.rst +++ b/Documentation/timers/no_hz.rst @@ -246,6 +246,9 @@ Known Issues be even worse than that of dyntick-idle. Furthermore, this parameter effectively disables Turbo Mode on Intel CPUs, which can significantly reduce maximum performance. + Note also that on nohz_full CPUs the scheduling-clock tick + is stopped while polling, so that it does not keep running + and interrupt the task once it resumes after idle. * Adaptive-ticks slows user/kernel transitions slightly. This is not expected to be a problem for computationally intensive -- 2.56.0