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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D0549C7618E for ; Sat, 22 Apr 2023 08:08:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229621AbjDVIIe (ORCPT ); Sat, 22 Apr 2023 04:08:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46542 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229451AbjDVIIc (ORCPT ); Sat, 22 Apr 2023 04:08:32 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD0BB1981 for ; Sat, 22 Apr 2023 01:08:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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; bh=ouu/rInpyYocF7+zLk5w+0lcXJWjye0/kyUDNTc5/o8=; b=KQp7XJd9UfTct6nM2xsUx27N9n hNGicymfEJ9TLaE+DsW8kzjg/ecz7lQF1cOl0c306RzxFoC6gnQfIzW/4jSSXjJyMV4QAwLIyRXF0 uwuuuqn30iNGPqgdhsVPw5z9yZqhUbJdyZs2VoTPTlYdI7op8R2jBCRF3Lk3AR4NJHeLKmCJ9H64k xku2dNrcWuIJS7lA/NUsYsU/UOnRDLRo7SR+ma13zP9ou2fFHXdIdY5C+aSw+nHJt+jqEsj1B6/Ik TRuSP/ehfmBMZAaYwto3O7fK+MyeyXW1FDhoBC+yuhaXo7YDn/fmHlTlv+yYK1750f8Rn8qJjFWfx 6MUViHyw==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1pq8I4-00G49A-Hg; Sat, 22 Apr 2023 08:08:17 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 6998D30035C; Sat, 22 Apr 2023 10:08:14 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 250F523BD94AA; Sat, 22 Apr 2023 10:08:14 +0200 (CEST) Date: Sat, 22 Apr 2023 10:08:14 +0200 From: Peter Zijlstra To: Frederic Weisbecker Cc: Huacai Chen , WANG Xuerui , Thomas Gleixner , "Rafael J. Wysocki" , Anna-Maria Behnsen , LKML Subject: Re: Loongson (and other $ARCHs?) idle VS timer enqueue Message-ID: <20230422080814.GA1214746@hirez.programming.kicks-ass.net> References: <20230421142446.GA1185829@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 21, 2023 at 06:47:29PM +0200, Frederic Weisbecker wrote: > > *HOWEVER* > > > > intel_idle_irq() is affected -- except that we only (normally) use that > > for very shallow idle states and it won't interact with NOHZ (because we > > only disable the tick for deep idle states). > > Well I don't know, that doesn't look comfortable... :) > > Also why does it need to enable IRQs if ecx=1 ? Supposedly this is some interrupt latency hack. See commit: c227233ad64c ("intel_idle: enable interrupts before C1 on Xeons")