From nobody Thu Apr 2 01:47:57 2026 Received: from mail-pg1-f178.google.com (mail-pg1-f178.google.com [209.85.215.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 646622D97B8 for ; Fri, 13 Mar 2026 03:48:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.178 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773373735; cv=none; b=P4TRS9tHuAeKWSKGWpk0GgfQ/BioXBI6P+ID1Pe3Wz4gOjcA+Oftuh3MSjUFpPvV2KtBIzAolDvI5WtAz5ORk006ohiRgX3bDoxsGctTXffydUCsTWTqiKj3I/A2KlMRWk49MXL7WGJR9WLiJZrYVmbMff5XaM0v5UTnAZxXzZ0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773373735; c=relaxed/simple; bh=9gCWfMsBdnmfbsBPei4ZMLQ0V9eHITrgA5NkNbVyC9Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uIP/i++RnNng61RPKOn3zCQhfRs0cwCC1lMYmrH4CJNDcp0To+5vww8BIwt6giQ7/FGGCZuBnSyzjl7HZrLdZe0mFcwPDZnfUl6c76M5/6BA5QwDuJso2JvzKVAzJPjsJAqyvZ4l6QTG9i8lNjXA3CwC92UqS2L4INYa4rFmavk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=EGP3yGE5; arc=none smtp.client-ip=209.85.215.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="EGP3yGE5" Received: by mail-pg1-f178.google.com with SMTP id 41be03b00d2f7-c7393536e53so693917a12.2 for ; Thu, 12 Mar 2026 20:48:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1773373734; x=1773978534; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=3upFcazwi0jm+8PpzRq3//QHHA7BPTHK0KEZHeSzb4Q=; b=EGP3yGE5Wdp5gYNPlcvtS7rMv6bjxdpv6gn5C6Y3NiyOdJ0WXmDvYBBwDoLiy5PZnu /6bz6GZxXXYnOKR9NkhvOxWcPGc7YIT3S2gnzOv5/afW52iP20lAWeESBv4G/S+ZQvlf vwl+thetuRrg3O0WO9k0vND9sangYhin7Ov7T8O00sFzu3CVbjdmMLKOGlLfMIIc6Xgb B5DiODbn5JmBUCj24jfp6xbdq8sYMU7qIJD3y8UynpqNNArN3i5/oHqUAeLgApL1nKMN kzRLrBqTucdREjst7XPVtxKXY2ZUyoswbpXO87ReShwnfxWNP32axEN8IQWUTYQd+42A X2/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1773373734; x=1773978534; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=3upFcazwi0jm+8PpzRq3//QHHA7BPTHK0KEZHeSzb4Q=; b=QTWIr6uYlxXXEFJ/RtzrYPRQpefxaG1yMVRXcbmH3TF/hj5TImcZgS2YeHhamWK+yD rm1F8I95LDZW+e4pH7J1kMnbeWbKXJ953fd2N9K2eUYnqlIRzYoCh9nyQUWLEQ7ZmrOO FD8/jOvWZYlWk6at8FA60G6nDgANJU7kuXfCNLmVRNKaEM2IBD0F5RY2+br57rrc1W4F IUR0Dq5CviU1fzmv8tzd8dSuLxqamx4RRfTaFx/Lp0YKV/2F6lD1rbhXAsXjSTCpg5Dl +vRNxu8qO9LR0L/FKecuootEq9YxKEQG0Jk3AyRjwwA0LFVDVFyKFgiDz66HbghmAN5C 9kRA== X-Forwarded-Encrypted: i=1; AJvYcCWThMUwPTDPlT9kJ7Jh/LeOUw6lxHD2HiUHtQ2ndhJE8mLqc65gQXOVDpBnVr8+jJKPPGrxF4BdEk/jBYo=@vger.kernel.org X-Gm-Message-State: AOJu0YzhBMZAWHyIKAYkBTlY8ufoIU+6MJYmQjqdbuvrNSbKXSl5w451 qNoZieXwPshd29+NehJXDNvGsfMZNc/2JvqrDx5h5+EZXxVulgyx/udX X-Gm-Gg: ATEYQzxq6L8YwdzDxWxPDR5fHivqosdmLQ++vWejqMqicyfA6qCohufdme9EOtvZGrk sVr0wq1GuizluvLINU1NwRTIhr9BDxV4PKLt9XPbUZbIHO688qxmykiCq+33j8tVVquGEl5M0qZ POWjDHay5l1h9gM/AnDqkMGX8iW2txounb2XXWTR5zLRsQMlsL1g8LMI4FAoGjl4vprpj+CKxE8 CExc0SnrdwbVAzpl4QZBYLM8EJ3iHSETRen9D+/dL3lstiuGqPCcDYQofuXFeURCzq7Y6Y/nPAG mZNm88BLq+o/2TB//71cXow3MOJev9PL9fyyxZYM4lLchjXLsuqWCQBZk70RLRoUAlrPLokPZYn HgwLRIwN0UkC/XbsgWkOOYr5QL0raYJS3Xi+pLQ0B07CV6k2HNYeFgs+jOlMylGMb7/zMDOJytW 4KD5iBkPbe72mUDusSy/RJsPPKLDkIM4+UB7F7JlDGrBcQcOE= X-Received: by 2002:a05:6a21:6088:b0:398:e2b9:ccca with SMTP id adf61e73a8af0-398ece012d2mr1320679637.62.1773373733717; Thu, 12 Mar 2026 20:48:53 -0700 (PDT) Received: from DESKTOP-MOQC9AF.mioffice.cn ([43.224.245.226]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-c73ebb75624sm467869a12.24.2026.03.12.20.48.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Mar 2026 20:48:53 -0700 (PDT) From: Zhan Xusheng X-Google-Original-From: Zhan Xusheng To: Johannes Weiner Cc: Juri Lelli , linux-kernel@vger.kernel.org, Zhan Xusheng Subject: [PATCH v3] sched/psi: Skip CPUs with zero non-idle jiffies in per-CPU aggregation Date: Fri, 13 Mar 2026 11:48:47 +0800 Message-ID: <20260313034847.1422-1-zhanxusheng@xiaomi.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260204022328.23938-1-zhanxusheng@xiaomi.com> References: <20260204022328.23938-1-zhanxusheng@xiaomi.com> 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" To improve performance during per-CPU aggregation, skip CPUs that have zero non-idle jiffies early in the process. These CPUs do not contribute to the weighted result and can be excluded from the per-CPU calculations. The change directly checks the `cpu_changed_states` for `PSI_NONIDLE` instead of performing unnecessary arithmetic. No functional change intended. Signed-off-by: Zhan Xusheng Reviewed-by: Johannes Weiner --- kernel/sched/psi.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index d9c9d9480a45..65f09282143e 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -384,6 +384,13 @@ static void collect_percpu_times(struct psi_group *gro= up, =20 get_recent_times(group, cpu, aggregator, times, &cpu_changed_states); + /* + * Skip CPUs with no non-idle time. These CPUs do not contribute + * to the weighted per-CPU aggregation, so we can avoid unnecessary + * calculations for them by checking cpu_changed_states. + */ + if (!(cpu_changed_states & (1 << PSI_NONIDLE))) + continue; changed_states |=3D cpu_changed_states; =20 nonidle =3D nsecs_to_jiffies(times[PSI_NONIDLE]); --=20 2.43.0