From nobody Fri Dec 19 00:39:12 2025 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3A4B22DB7C for ; Fri, 15 Dec 2023 13:05:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="rlNUTVj1"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="aCbWa5Az" From: Anna-Maria Behnsen DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1702645511; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=U2tDiKHKYr5BFBF9MXdN4euPv07ro9CC99NNHl3ihkg=; b=rlNUTVj11k9F9xc53az5oRZhTvMk3vR94kDWFOfa7PKvXnflbuwCP1YKdtZGHxLpdRhcgg fDm25g5wa4AfJJLPZK2dxPjsW2nBasLq4ivhyW54mNkGHLlGMcy46RAmGtr+8CtBkltUFP a00rKENsxQjPdgL8Wuhu8eWz9LhHREfhMsEashAZZ9/I0vIvFrbEle23ziddTULY32XYKT NURUrmnfZ/rMFgoT3TeGgb/Uoe4G7quDjS6FlR8LZFqtesbqjcADn2ZmTYx43LJZgjByGc MUOIjFrFOXGNCvrdwoTMJpXW9qa+k85M5Ox2A7EhML7EYrK0JtetLNekGnRN6w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1702645511; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=U2tDiKHKYr5BFBF9MXdN4euPv07ro9CC99NNHl3ihkg=; b=aCbWa5AznxUTz9+fLqfPxDsN2XeRkh9QsBGsRJ837u6cYvKn96zQhQAwbLWBVxvV1EGE+i +rFPQBp4IS/u5cCw== To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Valentin Schneider , Thomas Gleixner Subject: [PATCH] sched/idle: Prevent stopping the tick when there is no cpuidle driver Date: Fri, 15 Dec 2023 14:05:01 +0100 Message-Id: <20231215130501.24542-1-anna-maria@linutronix.de> 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" When there is no cpuidle driver, the system tries to stop the tick even if the system is fully loaded. But stopping the tick is not for free and it decreases performance on a fully loaded system. As there is no (cpuidle) framework which brings CPU in a power saving state when nothing needs to be done, there is also no power saving benefit when stopping the tick. Therefore do not stop the tick when there is no cpuidle driver. Signed-off-by: Anna-Maria Behnsen --- kernel/sched/idle.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 565f8374ddbb..fd111686aaf3 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -165,8 +165,6 @@ static void cpuidle_idle_call(void) */ =20 if (cpuidle_not_available(drv, dev)) { - tick_nohz_idle_stop_tick(); - default_idle_call(); goto exit_idle; } --=20 2.39.2