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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 7D67FC32771 for ; Sat, 18 Jan 2020 04:34:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3C15A24680 for ; Sat, 18 Jan 2020 04:34:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579322099; bh=1f8uxNZhSSDL1r1f/Wi9AKPe0gOnTUHVrR1Z9nAXJd8=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=ozKb2TrcJ4TB4S8mcWakHmVXd2jnyGpGnjRjUChf4o6w8Tnkcz3yqFSFPjsD3QIXa irAIPQxaLs2YxF2nFXFfmhBRKDEVZhctt2LklHcfbXZ4k/fthzIx337BqCQBIH3Ycm fYre1ea+0LsnwYtJJqV2X0/42ff5rEDn61xa+UIY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726896AbgAREe7 (ORCPT ); Fri, 17 Jan 2020 23:34:59 -0500 Received: from mail.kernel.org ([198.145.29.99]:32948 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726744AbgAREe6 (ORCPT ); Fri, 17 Jan 2020 23:34:58 -0500 Received: from paulmck-ThinkPad-P72.home (50-39-105-78.bvtn.or.frontiernet.net [50.39.105.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8138F2467F; Sat, 18 Jan 2020 04:34:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579322098; bh=1f8uxNZhSSDL1r1f/Wi9AKPe0gOnTUHVrR1Z9nAXJd8=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=rYNeNI3k4+V5dcprxU5e44OwKHQo7bnZ9t+rIuNjfnqgFTevVIqDXnHwFTtsVyjfr dcR13EJajQ/JCL8DiBReDsXK2wvPE4us4gW58o4zFE8qOyFgPLDUn+OFHxp1vSpcHI 82sTyYPZbYTEbeOlAHFFnZzVjb7/0d3qf5tHPUps= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 487F13522A3F; Fri, 17 Jan 2020 20:34:58 -0800 (PST) Date: Fri, 17 Jan 2020 20:34:58 -0800 From: "Paul E. McKenney" To: Joel Fernandes Cc: rcu@vger.kernel.org, rostedt@goodmis.org, bristot@redhat.com Subject: Re: RCU_BOOST not working for me Message-ID: <20200118043458.GT2935@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20200117215814.GB206250@google.com> <20200117221804.GA211665@google.com> <20200117231756.GO2935@paulmck-ThinkPad-P72> <20200118023434.GB244899@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200118023434.GB244899@google.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org On Fri, Jan 17, 2020 at 09:34:34PM -0500, Joel Fernandes wrote: > On Fri, Jan 17, 2020 at 03:17:56PM -0800, Paul E. McKenney wrote: > [...] > > But rcutorture already has tests for RCU priority boosting. Or are those > > failing in some way? > > Yes there are tests, but I thought of just a simple experiment to study this. > Purely since it is existing RCU kernel code that I'd like to understand. And > me/Daniel are also looking into possibly using run-time / trace-based > verification some of these behaviors. The functionality of rcu_state.cbovld should make that more entertaining. But I would guess that the initial model would ignore memory footprint and just model RCU priority boosting as kicking in a fixed time after the beginning of the grace period. Or do you guys have something else in mind? Thanx, Paul PS. Steve, yes, I do well remember our earlier discussions about readers inheriting priority from the highest-priority synchronize_rcu(). ;-)