From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 BC911377EC7 for ; Tue, 9 Jun 2026 12:34:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781008445; cv=none; b=Ls5HAwIsxfCL5dS4fKn1XZvletaoIl8mKeVwyCTnCNn19QM3JFD9mB0Ch02qyXmUmFj7LuOULJI9/czquJV0WeKaCKhj52zBhfBqOl8l3oGJ2FC7JHoWo4OC1J2MpKUD0wyJQtRIPsCZA25i61wQfvCCrE+/0BlWgqIoUvcCusk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781008445; c=relaxed/simple; bh=33UsDyp2J1YWDTXVQ5N/NpgZFg25wbGnibeGU1rAZOg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=m/sWT1KRp6VwDA6K6SO2rqjxAtHMois0KVUO/LO5BPAL6sG3eq8jtf3IqtWET2tVWfbkWGdvASHAr2wVh9tMxgRhg331r+uBQAhgCv9nx6Eg8U1jQtOUKaeA795q11RHESI9TmWMhJ8F6SNkj8QzKtJv9ghGZyJr6dqp+v2kmeo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Uy7beH0D; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Uy7beH0D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E09631F00898; Tue, 9 Jun 2026 12:34:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781008444; bh=HBvrw+Y659iwgxj+/RIwozQP6O/YHKvnPg5/ZXJDoiE=; h=From:To:Cc:Subject:Date; b=Uy7beH0DHE4Kc5wXhwLR1ShO5ZwghzDR7a2d8RBr7gC9VjqkFN34MT23GNk9OYO9o vHPosh8amajqPQ+/I7aNmgKXLpd6ZadPj4K4wm/Au5zGdCHoirMCiVGqV2XOh9AU9F iCvh5+NhuZk7VOCpa7UDszsj5ZG8ZQHWVTbAZOMktNNl4JRmm75m5++6gMdXFAziIp o4XyTS4KA2Ah52Q138CxxZQinvD40h2PRs+fK6/3ela71Hodg/aoyQBlUsaoVfT4QF 4nUccKlYNnkKezO1iAKUJQscnA1hiutM4u/ulDUNJ8AvDuAxxkV42FmcKyF86vWmzh roR3C7GkyxuCQ== From: Frederic Weisbecker To: Thomas Gleixner Cc: LKML , Frederic Weisbecker , Sehee Jeong , Anna-Maria Behnsen , Christian Loehle Subject: [PATCH] timers/migration: Temporarily disable per capacity hierarchies Date: Tue, 9 Jun 2026 14:33:56 +0200 Message-ID: <20260609123356.28449-1-frederic@kernel.org> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Some workloads with different CPU capacities consume more power with timer migration than before. The recently introduced per capacity hierarchies were supposed to alleviate this problem. However it appears to also regress other types of workloads, especially when plenty of capacities live together in the same machine. Disable the feature until a reasonable solution is found. Fixes: 098cbaad8e57 ("timers/migration: Split per-capacity hierarchies") Reported-by: Christian Loehle Signed-off-by: Frederic Weisbecker --- kernel/time/timer_migration.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/time/timer_migration.c b/kernel/time/timer_migration.c index 548d84955f4c..e9d96d96e251 100644 --- a/kernel/time/timer_migration.c +++ b/kernel/time/timer_migration.c @@ -1473,7 +1473,7 @@ static unsigned int tmigr_get_capacity(int cpu) * timekeeper must then belong to the same hierarchy as all the nohz_full * CPUs. Simply turn off capacity awareness when nohz_full is running. */ - if (tick_nohz_full_enabled()) + if (tick_nohz_full_enabled() || !IS_ENABLED(CONFIG_BROKEN)) return SCHED_CAPACITY_SCALE; else return arch_scale_cpu_capacity(cpu); -- 2.53.0