From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793866267; b=Nqihqm/qYQLfPXLrxlzv9M/bbpo4V6TEFSgicZgIubDLTBvhFsh72hlZ9ZPoJKhCgwGy 7McgLI6xmOGXi/Tj+GC1KfIfSODkpAeja+RWAoUatIQctRpye6UtqV0fGHyvSlpNHnoMO +WhUa/gcnhoIDmgAFRYGEL8u53v4m5KLK/I+3njXPfjNefSWJYVLsWn9ChAZDwifAkE7N HNx4TKjsqmAWl/6d8KxttO9a9JUojdMnXkOrOItcskdWV1wZydl7ViKQmi/RHWuHwE3eo SGlEkDIvcNX2nT5vVuciTYjboOd4m7unmOYNKe/hDX048lNrQJY6JlNLhzC25L+QWdQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793866267; h=DMARC-Filter:Received:Received:DKIM-Signature:Message-ID:Date: MIME-Version:User-Agent:Subject:To:Cc:References:Content-Language: From:In-Reply-To:Content-Type:Content-Transfer-Encoding; bh=k2kV++0KkLBH5brlnSSDfSfy6EkjMYv+IqlDHzr/Zis=; b=x5WXpiKxo+NgRqobKBESoKiDwbG9tUo0SypnZin2uIo9GyxbpIIaGungJjKSQZjcT0fc fyexrZAZeSgq0xe+wPWQ7sGUSScnMEfEOppcfkS0bNWJSv547oIPu7kA9zqpDhXtgSlGE LrWk3k+lQqUBUNTuPamX1nWCzZu/kDcC87dCYUQ//L0JfuB46nGwp6EP/ZwaZNrfaVrZJ ANHjaP1h/ayKMOLrmmKv1goA6M5I1yiws/B+5HyEuDymnpHguNTMc7JxhFEQ+bjR2pt4m kSlpPgUZZKAD5o+RKi3Ag+mxPaorz8jWcgpLrRLoiJ7sR208PMEYpUlspV7yIy7MD6w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=XnEQ10Fp; arc=none smtp.remote-ip=217.140.110.172 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 4C758606A326; Thu, 5 Nov 2026 08:11:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 4C758606A326 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=XnEQ10Fp Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5188D152B; Thu, 5 Nov 2026 00:11:01 -0800 (PST) Received: from [10.57.17.2] (unknown [10.57.17.2]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8E8123F673; Thu, 5 Nov 2026 00:11:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1793866264; bh=guG2LxtQjqQSAz+GSbDIH/DgynW4RmuQ4u309BCNpTY=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=XnEQ10Fp716oYvC3kMcPoqBk4TfdLNY3AuYHhNtItluOg2z+D1JSu09JdSm/um7XU 2ZSzsM8/XOG7pBy7p7vHwQ10/3ojbBQYu+VB1NgV/KuY3Xe/spJi7JGAInEH71Y+QP sGb2lQg39/w9Tf6f5T/1XJ1r89mlhQuJgpT9Bv9M= Message-ID: Date: Thu, 5 Nov 2026 08:11:01 +0000 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/2] cpuidle: idle_miss accounting fixes To: "Rafael J . Wysocki" , Daniel Lezcano Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20261030083633.1699270-1-christian.loehle@arm.com> Content-Language: en-US From: Christian Loehle In-Reply-To: <20261030083633.1699270-1-christian.loehle@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/30/26 08:36, Christian Loehle wrote: > These two fixes exclude timer-broadcast fallbacks from governor miss > accounting and respect the entry-time latency constraint when looking for > a better deeper state. > No functional change outside of sysfs above/below and tracing. > > Patch 1: Exclude timer-broadcast fallbacks > > When tick_broadcast_enter() fails, the core forces a shallower state. > Exclude these entries from governor miss accounting while retaining > residency, usage and governor feedback. > > On Orion O6, traces with menu and TEO running schbench, tbench and hackbench > recorded 6930 cpu_idle_miss events on 8172 broadcast fallbacks before the > fix, and none on 7763 fallbacks with patch 1. All matched fallbacks entered > WFI. > > Patch 2: Respect latency constraints for below misses > > An enabled deeper state may violate the latency QoS constraint, causing a > false below miss. Save the governor latency limit at entry and exclude > states exceeding it, without an additional state-table walk. Disable flags > continue to be checked at exit as they are expected to change less frequently. > > Christian Loehle (2): > cpuidle: Skip miss accounting for timer broadcast fallbacks > cpuidle: Respect latency constraints when accounting below misses > > drivers/cpuidle/cpuidle.c | 16 +++++++++++++++- > 1 file changed, 15 insertions(+), 1 deletion(-) > Rafael, any opinions?