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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 1796CC352A4 for ; Mon, 10 Feb 2020 22:35:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B5C2A20733 for ; Mon, 10 Feb 2020 22:35:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581374148; bh=82MflMcVGrmt5MUVdc81CJL6FsYuXLCsmLVCoby/PDA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=szZ7vYYuxRqadrYMcihZlcEGtJRzLFqTN79ar3J2U8MiTb5cusTy6isOdCQyjlp4i 5iYRwmbLZPG6YY6A/P1mAWfwKS6xs5Qfx6X0LQpAiQiewAoQPxrqewvqi3Aeb8Ph4c SurvUfT8DsO866W0J9oN7q8kzVjVuGWu9B0seIz4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727523AbgBJWfs (ORCPT ); Mon, 10 Feb 2020 17:35:48 -0500 Received: from mail.kernel.org ([198.145.29.99]:38468 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727422AbgBJWfr (ORCPT ); Mon, 10 Feb 2020 17:35:47 -0500 Received: from akpm3.svl.corp.google.com (unknown [104.133.8.65]) (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 E91792082F; Mon, 10 Feb 2020 22:35:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581374147; bh=82MflMcVGrmt5MUVdc81CJL6FsYuXLCsmLVCoby/PDA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=I3IdaBh/8Z59OiKykBh+V8G/EgR798P7TPHUJGrBpd84Ff/TPO0S0VpOStU5xiec9 HH3/vLtUQ+LRx9b4atJDI6GHwGrBvRSj2OQujL9M/xSOe5L3JIfVPevKOQdrZKBg19 kjIpnVeFF7ypVxImosOnulkEEgUNmjdA/ludY4Po= Date: Mon, 10 Feb 2020 14:35:46 -0800 From: Andrew Morton To: Davidlohr Bueso Cc: linux-kernel@vger.kernel.org, mcgrof@kernel.org, broonie@kernel.org, alex.williamson@redhat.com Subject: Re: [PATCH -next 0/5] rbtree: optimize frequent tree walks Message-Id: <20200210143546.4491d9715f1c4a0a1de999ca@linux-foundation.org> In-Reply-To: <20200210155611.lfrddnolsyzktqne@linux-p48b> References: <20200207180305.11092-1-dave@stgolabs.net> <20200209174632.9c7b6ff20567853c05e5ee58@linux-foundation.org> <20200210155611.lfrddnolsyzktqne@linux-p48b> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 10 Feb 2020 07:56:11 -0800 Davidlohr Bueso wrote: > On Sun, 09 Feb 2020, Andrew Morton wrote: > >Seems that all the caller sites you've converted use a fairly small > >number of rbnodes, so the additional storage shouldn't be a big > >problem. Are there any other sites you're eyeing? If so, do you expect > >any of those will use a significant amount of memory for the nodes? > > I also thought about converting the deadline scheduler to use these, > mainly benefiting pull_dl_task() but didn't get to it and I don't expect > the extra footprint to be prohibitive. > > > > >And... are these patches really worth merging? Complexity is added, > >but what end-user benefit can we expect? > > Yes they are worth merging, imo (which of course is biased :) > > I don't think there is too much added complexity overall, particularly > considering that the user conversions are rather trivial. And even for > small trees (ie 100 nodes) we still benefit in a measurable way from > these optimizations. > Measurable for microbenchmarks, I think? But what benefit will a user see, running a workload that is cared about?