From nobody Sun Feb 8 05:23:54 2026 Received: from mail-pf1-f170.google.com (mail-pf1-f170.google.com [209.85.210.170]) (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 8B2A02609FD for ; Wed, 4 Feb 2026 02:23:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.170 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770171817; cv=none; b=gpCHsqC9TJ3UiELyX1FLrqnqEcmsYRvJc0h11TsLtFiHuWnkSfPDkIVLHc02VycMKZh10AqrloPx+pvasyoNO6B4a4PWOoh8c8XZNx1SzUqgEzAHNC67iQlZHCfzk/n5lAmfdj3ACBhM4L+B00/ai0AVgnq2oPkECo24YbmmfZM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770171817; c=relaxed/simple; bh=aa8oRthNSMGShuFw0Ewu27XlBvq1J80HVJc/RbGKB8s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BJ6xdA39vlqT4PoHw1kDHM4dov/QNYMoOKk7UcOw/AMdFnA36cFDnUmKKvU3Rqd1WEp9moWHDB1bOe1CAToQx6GSF2kCVCtSR2xjjUHGKkHe7ormdUM5RwRnMvJNamy8q2C89K+XMCjDXigIdWMWc7IvSmhH+SnZ34CWrrSHm+E= 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=A8ogOMlj; arc=none smtp.client-ip=209.85.210.170 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="A8ogOMlj" Received: by mail-pf1-f170.google.com with SMTP id d2e1a72fcca58-81f39438187so3704916b3a.2 for ; Tue, 03 Feb 2026 18:23:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1770171815; x=1770776615; 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=qmioQC8wcD1pAtj87sIRPLJE0HJ/M/AU1bd/B29nqoI=; b=A8ogOMljTaYRiskMG6FuOaCqQjmepXn7WDbk+BOD93P4C5uABFSk1uwbgUvTmVnm+w T7r5+F+l/lEFVX2GN931yTNOMQto58bTOhqILCQd2z3DySuxsHJAsdF+7yip012mbJMr J7ZTs3w4EjU7D3lkMX4FufClrZi4kcGgDHXAaNlqjboWj/WE9lXrYXptv5jrB0nwswrD gh18O1mnQBBN0TyDf0OX4j/8xp164Li4mxThmPb0kT2TQNVXZZPgZQjCkdxIjMrmQsXy 2C8un0GYZi6SKvx+FDMjJZ0ZgEXLkJuvCGCCsMEzSmxSab5l80EFFuZv+EvrDLf4bs32 4zFA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770171815; x=1770776615; 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=qmioQC8wcD1pAtj87sIRPLJE0HJ/M/AU1bd/B29nqoI=; b=hoUmm0nvPB6wjt5BU0asE6n6GbZYypDy4F+hhflGvu1rrRnU/dJ2tM5mJP45gnnUoz 1UwU6DztpNIzln+5BRYXCzpAQHO0iPOOV0dADiZt7p5+aCrwmWU9VUsD/cdvk1ZTr017 SPX9e8QKzFtRd627xsGlU3Fy8rVjId69rW+HvOaseiI394gHBzjArNUL7JgrlGotIASR xz8hPTR5f7YplXaD0UTuul4qm8ytO5Wf+Tkko8Z37uMJI4AzKFfEuF8gazqUzJiAi1L+ amqQXZ0ZJXZkpzqVQpGx62squM2i2NvT8MpGYOFm/Hs3bjBjsyzqIt+eCRb9KeHnGICF COdA== X-Gm-Message-State: AOJu0YytidGm0u/0zxMXMrfZy/ctPv8ENwvCQ4IXPdhC4GvmqaRgyEcs YRvISbSFXU7bAIOBInAqOtaGuBHESSSL7y6HvL4Ykc1gRzNExnRiS9KZ X-Gm-Gg: AZuq6aITvBZ3Y3UwFfK4v8hJXBw03TYJ5sSCvdZUqo2G8FmhOX9vMpkzXiTHCFgUtIr 3Cve6E1i9EDS7Eq1Y+mTGpdVpS7/ZM0HnVZ1AiZAvXOjR0YGY6qKB6wzukl6lKEx5En7Sn1ShL2 g16kAc9S2+7XFSP2cYc1hFk0j33hpoAmkEmmvoZoF0YqfaH9U4Z3uf+ZLHlFMgkxZu1K7pFPo3e mgK60RG3rlw9wquNpsnBRTKWSVDuzNedCqjJry5FUHM0uZSFOsTO80QG7nul5uP0d5JBb2kgNfD mpzynLFucBSSg+K0lVR34cyfrCVVdfqEyDAqsJruzzcKQSHvuFQ3qrMdSollDolilCpsOxX9hSK audFBIfSFMP9t+2WJ6d8J2YVbR/uJlqy0Iw4wJIP/1evtyVzOIjldJOkRxlrAmC9/xreaU2nd2f aR90zzMc9dSp7kGTjrEhkmNXOw+x/vUAErenU= X-Received: by 2002:a05:6a00:12c3:b0:81e:b2ba:5b3a with SMTP id d2e1a72fcca58-8241c1ab50amr1281321b3a.8.1770171814790; Tue, 03 Feb 2026 18:23:34 -0800 (PST) Received: from DESKTOP-MOQC9AF.mioffice.cn ([43.224.245.239]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-8241d163b8asm701635b3a.1.2026.02.03.18.23.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Feb 2026 18:23:34 -0800 (PST) From: Zhan Xusheng X-Google-Original-From: Zhan Xusheng To: Johannes Weiner Cc: linux-kernel@vger.kernel.org, linux-sched@vger.kernel.org, Zhan Xusheng Subject: [PATCH v2] sched/psi: Skip CPUs with zero non-idle jiffies in per-CPU aggregation Date: Wed, 4 Feb 2026 10:23:28 +0800 Message-ID: <20260204022328.23938-1-zhanxusheng@xiaomi.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: 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 59fdb7ebbf22..f1bf5449d3f9 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