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 B9DADC433EF for ; Sat, 5 Feb 2022 00:21:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378743AbiBEAVT (ORCPT ); Fri, 4 Feb 2022 19:21:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59130 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239683AbiBEAVT (ORCPT ); Fri, 4 Feb 2022 19:21:19 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C6085DF8E3CA; Fri, 4 Feb 2022 16:21:16 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 83D68B83860; Sat, 5 Feb 2022 00:21:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B634C004E1; Sat, 5 Feb 2022 00:21:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1644020474; bh=iAGTjf0kijpYGD/tXeU0h8B4bIEAsKJc+hhSN0LFTdA=; h=Date:From:To:Cc:Subject:Reply-To:From; b=iOPmdTo2cepGZnmVkpZSQFImkOQRaux2/B6knHg6pYqQ1Pf+X8XSdWzmuszXgu5u1 jRqp+5UJiRi40d8mA0OLSxXCtTsCmTUe83IQ7TJVUr/V2HgXLi7eQeKaL+CDWOMu0A ekD61HRqlwuN6bfoYzcBbIp+luLmhGAc87RhGdntUsz3tMy2P+KQSpba6E6Nb29pNm blb88XhiR4ARvVeckTKeOm9g0azjTvS9wmCN3vOHji2CgSoVH+DzSusmMp7ZF+XA58 cj5Xip91kXrf0eBznUGAakf6NjJMJLuhQy0oXkEQzak0fvGUyaQ07qRfXxLRG8U6Oz EOMUD4iKOJCCw== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id D417B5C0418; Fri, 4 Feb 2022 16:21:13 -0800 (PST) Date: Fri, 4 Feb 2022 16:21:13 -0800 From: "Paul E. McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com, rostedt@goodmis.org Subject: [PATCH rcu 0/2] RCU tasks updates, possibly for v5.18 Message-ID: <20220205002113.GA4693@paulmck-ThinkPad-P17-Gen-1> Reply-To: paulmck@kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello! This series provides a couple of updates to the RCU Tasks flavors. 1. rcu-tasks: Use order_base_2() instead of ilog2(). This spreads CPUs over queues more evenly. 2. rcu-tasks: Set ->percpu_enqueue_shift to zero upon contention. The current mainline series reduces contention by at most a factor of two. This patch gains at least another factor of eight during times of high update-side traffic. Thanx, Paul ------------------------------------------------------------------------ b/kernel/rcu/tasks.h | 6 +++--- kernel/rcu/tasks.h | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-)