From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.4 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37B8FC4321D for ; Mon, 20 Aug 2018 11:04:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA11121570 for ; Mon, 20 Aug 2018 11:04:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Jmzn1ipG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DA11121570 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726580AbeHTOTW (ORCPT ); Mon, 20 Aug 2018 10:19:22 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:43846 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725948AbeHTOTW (ORCPT ); Mon, 20 Aug 2018 10:19:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=xtHmHAVF7pnDJTgigaQXYkhAdYbKy1SNx2gDcWyB5IY=; b=Jmzn1ipGkJ+AlJ9SsFAhm4iJj oX6a7Sia+ZgASiJ53sNZdHNp2W6pICkQ3swEWny3NhN5B7iu+x/eHAtDrp6jIpMnghGcrWyFTWADE YBMjrZ+gu54WUMq1vGGcM5uSruSTPE6Qd+kpKVQHKgMAl26XVjZtectnufvgFegZvtX0JkjKQHASG tp88bCtKnP+JwNLW97q2ZlcksjUVXxXf7UkTOzHARKr0gDuOqpd0tEZRzFwmlReNnHg9I0HT8sWDB 6vfu33HFg7BTKQlUGbtZt/CsjGcZThiuAaseWqKU+pcaQdUcrAbAJNBmB83415tWRt8sD66EP5YJU QPh7CO8Ow==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1frhyl-0001kz-Jj; Mon, 20 Aug 2018 11:04:11 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 0A06820267B13; Mon, 20 Aug 2018 13:04:10 +0200 (CEST) Date: Mon, 20 Aug 2018 13:04:10 +0200 From: Peter Zijlstra To: leo.yan@linaro.org Cc: "Rafael J. Wysocki" , Linux PM , LKML , Frederic Weisbecker Subject: Re: [PATCH v5] cpuidle: menu: Handle stopped tick more aggressively Message-ID: <20180820110410.GY2494@hirez.programming.kicks-ass.net> References: <1951009.1jlQfyrxio@aspire.rjw.lan> <1754612.IcCR94pSYR@aspire.rjw.lan> <1582055.9b67urWYFa@aspire.rjw.lan> <1572343.jWaXB8XNF1@aspire.rjw.lan> <20180814154441.GA13920@leoy-ThinkPad-X240s> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180814154441.GA13920@leoy-ThinkPad-X240s> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 14, 2018 at 11:44:41PM +0800, leo.yan@linaro.org wrote: > I agree this patch can resolve the issue you mentioned in the commit > log, but this patch will be fragile for below case, so it will select > state1 but not state2, how about you think for this case? > > Idle_state0:: > target_residency TICK_USEC Prediction > | | / > V V / > -----------------------------------------------------> Time length > ^ ^ > | | > Idle_state1: Idle_state2: > target_residency target_residency If someone can demonstate this is an actual problem; then we need to fix it I suppose. But it would be very good to have a real world need/reproducer for it first.