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Tue, 27 Jan 2026 23:47:16 -0800 (PST) Received: from ionutnechita-arz2022.local ([2a02:2f07:6017:b500:fda1:539e:7acb:2db8]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4806d255fc7sm3499985e9.0.2026.01.27.23.47.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Jan 2026 23:47:15 -0800 (PST) From: "Ionut Nechita (Sunlight Linux)" To: Thomas Gleixner , Frederic Weisbecker Cc: Ionut Nechita , Ingo Molnar , Anna-Maria Behnsen , Ionut Nechita , linux-kernel@vger.kernel.org Subject: [PATCH] tick/nohz: Optimize check_tick_dependency() with early return Date: Wed, 28 Jan 2026 09:45:43 +0200 Message-ID: <20260128074558.15433-3-sunlightlinux@gmail.com> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Avoid iterating through individual tick dependency bits when the tick_stop tracepoint is disabled, which is the common case. When tracing is disabled, we can return immediately based on the atomic value being zero or non-zero, skipping the per-bit evaluation. This optimization improves the hot path performance of tick dependency checks across all contexts (idle and non-idle), not just nohz_full CPUs. Suggested-by: Thomas Gleixner Signed-off-by: Ionut Nechita --- kernel/time/tick-sched.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 34b341b66f220..2c1236a1cd364 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -332,6 +332,9 @@ static bool check_tick_dependency(atomic_t *dep) { int val =3D atomic_read(dep); =20 + if (likely(!tracepoint_enabled(tick_stop))) + return !val; + if (val & TICK_DEP_MASK_POSIX_TIMER) { trace_tick_stop(0, TICK_DEP_MASK_POSIX_TIMER); return true; --=20 2.52.0