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=-6.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 E366CC433E0 for ; Fri, 12 Feb 2021 14:21:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AD8CD64E57 for ; Fri, 12 Feb 2021 14:21:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231894AbhBLOVE (ORCPT ); Fri, 12 Feb 2021 09:21:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:44922 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232168AbhBLOUk (ORCPT ); Fri, 12 Feb 2021 09:20:40 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id B916264E3D; Fri, 12 Feb 2021 14:19:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1613139600; bh=Uyda5wqPFSXXYn0InDCALReOlU9knHM6ts9+78opvV4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GF1btb9C8VQhIWXaD+8A9iNaR2kr9UPOlayuqleqR5YRrTQZdqyDhZ2pV4WmaySJW 7z17YmclVEMfyj7f6g2Z9DhfYjUSgdfmgH9GSbXb7R90s7ha2vl6Dgrx1zviEdDI4a 3CokL4NYcN6pm91bkF4sJOME284fNp44OCX+Lfl4s2eywu9ZAepIzkdJ4tKM7NZCfG ESyUa/Ll0UVLDgmUPYs0aHevQctWlsZCFakiUwP/A0tmsC2XyM/JYL5nOFVuOp2BYE y+D47cWRBP9kan2dgTvY1zCMzSZDqAE1DPcmuReHOYSq1CCsRQ3ga5/IVmBs9VB88u jlD/gh/8ATrOQ== Date: Fri, 12 Feb 2021 15:19:57 +0100 From: Frederic Weisbecker To: Marcelo Tosatti Cc: Peter Zijlstra , linux-kernel@vger.kernel.org Subject: Re: [patch 0/3] nohz_full: only wakeup target CPUs when notifying new tick dependency (v5) Message-ID: <20210212141957.GB94816@lothringen> References: <20210128202134.608115362@fuller.cnet> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210128202134.608115362@fuller.cnet> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 28, 2021 at 05:21:34PM -0300, Marcelo Tosatti wrote: > When enabling per-CPU posix timers, an IPI to nohz_full CPUs might be > performed (to re-read the dependencies and possibly not re-enter > nohz_full on a given CPU). > > A common case is for applications that run on nohz_full= CPUs > to not use POSIX timers (eg DPDK). This patch changes the notification > to only IPI the target CPUs where the task(s) whose tick dependencies > are being updated are executing. > > This reduces interruptions to nohz_full= CPUs. Looks good. I'm queueing the series if Peter doesn't object. Thanks!