From nobody Sun Feb 8 06:56:10 2026 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 7083E22D78A; Fri, 23 Jan 2026 11:06:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769166401; cv=none; b=WqFTIeMIYLiOpFWUlhs6TL8iJqCfWN23l7f9gkdLniqtk9rWyHc2ZjtJxyI4qrBf1qw7cpV0n7AniFqzHXJ3MTjcILYfy6vsC0tj5zC4871ZQ87dF1KaU5JbFJIgcUrt1v3uutAIf0b62trp6jeDhiGSFPUspEVWFhU7dZSNsyU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769166401; c=relaxed/simple; bh=tKd93ga5a7moVM0XH6sUTYmYj6Lo5N06bf5MXBX1XTY=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=dwzpL+MibFZQ7SrlpwaScDpeEq1DHfHPsOzCQYI7wPYHFkBbN5wSd0Jdj0f91JFtYJE19uRYQMHyN3WycubLBHVW5jP5OYFASOOksHxFhU6e+7JWb8fkezJ5rY7ewg6cvK0BMoy2u+Wji4nL+5/HQLl8J7OHbxqTg0zzl+AyLGw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=gePLasUa; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=OPPbXe2X; arc=none smtp.client-ip=193.142.43.55 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="gePLasUa"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="OPPbXe2X" Date: Fri, 23 Jan 2026 11:06:37 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1769166399; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VYdWlWFd3IO2DkGMQjiFrCIxxS62GcFeAumGiL31uf0=; b=gePLasUa9NRnxYJbINk7S2SeJ96nu6ZyJdz1cPuRgcr1zOFUXcFeUfE6PArAd+/1LIAAME iebvU1LhYqcBA84iOsmhAA9FxlDiYCJdNSs7tkdem2MPp6N/WcJsjzreJWH875cToE/0kG v3y2Jqsx9SowGYTvA5LoIzDqoe8iCVAiN5VnrgwlXrDSHirlsNsAPzYDTfUonynwByNmYZ FEXxhGTY5gvbU2F9JjJk6c3K9lJZF1VI8dIevsZGktwvl6ShIXX3SARoenvc/dwKzpZtNX 4Xx4UlvbIifAJ+gdlKClUZ6/DKZKWshw0lfrGf3/v1el3stjyrm4H9foPEJwPQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1769166399; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VYdWlWFd3IO2DkGMQjiFrCIxxS62GcFeAumGiL31uf0=; b=OPPbXe2XVPguZ16Q7y/ZQACzLjxc0KMmxbdDbMS9qSCzPFP4ylfKWZm3Hnu5I74uBiIrEA DatZ6JQSB15hoSDg== From: "tip-bot2 for Mel Gorman" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/urgent] sched/fair: Disable scheduler feature NEXT_BUDDY Cc: Mel Gorman , "Peter Zijlstra (Intel)" , Madadi Vineeth Reddy , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <176916639767.510.9429247977258489348.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the sched/urgent branch of tip: Commit-ID: 4f70f106bca1a56bd66d00830ac91680bd754974 Gitweb: https://git.kernel.org/tip/4f70f106bca1a56bd66d00830ac91680b= d754974 Author: Mel Gorman AuthorDate: Tue, 20 Jan 2026 11:33:35=20 Committer: Peter Zijlstra CommitterDate: Fri, 23 Jan 2026 11:53:19 +01:00 sched/fair: Disable scheduler feature NEXT_BUDDY NEXT_BUDDY was disabled with the introduction of EEVDF and enabled again after NEXT_BUDDY was rewritten for EEVDF by commit e837456fdca8 ("sched/fai= r: Reimplement NEXT_BUDDY to align with EEVDF goals"). It was not expected that this would be a universal win without a crystal ball instruction but the reported regressions are a concern [1][2] even if gains were also reported. Specifically; o mysql with client/server running on different servers regresses o specjbb reports lower peak metrics o daytrader regresses The mysql is realistic and a concern. It needs to be confirmed if specjbb is simply shifting the point where peak performance is measured but still a concern. daytrader is considered to be representative of a real workload. Access to test machines is currently problematic for verifying any fix to this problem. Disable NEXT_BUDDY for now by default until the root causes are addressed. Signed-off-by: Mel Gorman Signed-off-by: Peter Zijlstra (Intel) Tested-by: Madadi Vineeth Reddy Link: https://lore.kernel.org/lkml/4b96909a-f1ac-49eb-b814-97b8adda6229@arm= .com [1] Link: https://lore.kernel.org/lkml/ec3ea66f-3a0d-4b5a-ab36-ce778f159b5b@lin= ux.ibm.com [2] Link: https://patch.msgid.link/fyqsk63pkoxpeaclyqsm5nwtz3dyejplr7rg6p74xwem= fzdzuu@7m7xhs5aqpqw --- kernel/sched/features.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 980d92b..136a658 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -29,7 +29,7 @@ SCHED_FEAT(PREEMPT_SHORT, true) * wakeup-preemption), since its likely going to consume data we * touched, increases cache locality. */ -SCHED_FEAT(NEXT_BUDDY, true) +SCHED_FEAT(NEXT_BUDDY, false) =20 /* * Allow completely ignoring cfs_rq->next; which can be set from various