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=-10.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 4A17FC55ABD for ; Fri, 6 Nov 2020 12:46:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF988206B7 for ; Fri, 6 Nov 2020 12:46:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="iOPvJyEq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727169AbgKFMqf (ORCPT ); Fri, 6 Nov 2020 07:46:35 -0500 Received: from fllv0015.ext.ti.com ([198.47.19.141]:51916 "EHLO fllv0015.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727020AbgKFMqf (ORCPT ); Fri, 6 Nov 2020 07:46:35 -0500 Received: from lelv0266.itg.ti.com ([10.180.67.225]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 0A6CkLWY099280; Fri, 6 Nov 2020 06:46:21 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1604666781; bh=86PyDEAGqhTlwQYgakhBuJ6yxMtyDVOfU+4SvvgVLH4=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=iOPvJyEqx81hPfSNxpbLVH1B49X75y6mM0M8awv4dbpq4SMSPV3V5D+7ZqDs3b58j kaXzqVmeJvP7wA6DC+c/KT3ww+OzFgE15Jj3MtIVYTJwFbJS41wteWHoht8TB8AibN EZFWnYevQBpVLoKc5/Xl5YfY0riPSmK3V5eJlygQ= Received: from DLEE100.ent.ti.com (dlee100.ent.ti.com [157.170.170.30]) by lelv0266.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 0A6CkLbr030568 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 6 Nov 2020 06:46:21 -0600 Received: from DLEE102.ent.ti.com (157.170.170.32) by DLEE100.ent.ti.com (157.170.170.30) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3; Fri, 6 Nov 2020 06:46:20 -0600 Received: from lelv0326.itg.ti.com (10.180.67.84) by DLEE102.ent.ti.com (157.170.170.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3 via Frontend Transport; Fri, 6 Nov 2020 06:46:21 -0600 Received: from [10.250.100.73] (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0326.itg.ti.com (8.15.2/8.15.2) with ESMTP id 0A6CkGqe084078; Fri, 6 Nov 2020 06:46:17 -0600 Subject: Re: [PATCH v1 00/18] Refactor fw_devlink to significantly improve boot time To: Saravana Kannan , Laurent Pinchart CC: "Rafael J. Wysocki" , "Rafael J. Wysocki" , Len Brown , Greg Kroah-Hartman , Ard Biesheuvel , Rob Herring , Frank Rowand , Marc Zyngier , Thomas Gleixner , Tomi Valkeinen , Android Kernel Team , ACPI Devel Maling List , LKML , linux-efi , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" References: <20201104232356.4038506-1-saravanak@google.com> <20201106050940.GG16469@pendragon.ideasonboard.com> From: Grygorii Strashko Message-ID: Date: Fri, 6 Nov 2020 14:46:25 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On 06/11/2020 10:36, Saravana Kannan wrote: > On Thu, Nov 5, 2020 at 9:09 PM Laurent Pinchart > wrote: >> >> Hi Saravana, >> >> Thank you for working on this ! >> >> On Wed, Nov 04, 2020 at 03:23:37PM -0800, Saravana Kannan wrote: >>> The current implementation of fw_devlink is very inefficient because it >>> tries to get away without creating fwnode links in the name of saving >>> memory usage. Past attempts to optimize runtime at the cost of memory >>> usage were blocked with request for data showing that the optimization >>> made significant improvement for real world scenarios. >>> >>> We have those scenarios now. There have been several reports of boot >>> time increase in the order of seconds in this thread [1]. Several OEMs >>> and SoC manufacturers have also privately reported significant >>> (350-400ms) increase in boot time due to all the parsing done by >>> fw_devlink. >>> >>> So this patch series refactors fw_devlink to be more efficient. The key >>> difference now is the addition of support for fwnode links -- just a few >>> simple APIs. This also allows most of the code to be moved out of >>> firmware specific (DT mostly) code into driver core. >>> >>> This brings the following benefits: >>> - Instead of parsing the device tree multiple times (complexity was >>> close to O(N^3) where N in the number of properties) during bootup, >>> fw_devlink parses each fwnode node/property only once and creates >>> fwnode links. The rest of the fw_devlink code then just looks at these >>> fwnode links to do rest of the work. >>> >>> - Makes it much easier to debug probe issue due to fw_devlink in the >>> future. fw_devlink=on blocks the probing of devices if they depend on >>> a device that hasn't been added yet. With this refactor, it'll be very >>> easy to tell what that device is because we now have a reference to >>> the fwnode of the device. >>> >>> - Much easier to add fw_devlink support to ACPI and other firmware >>> types. A refactor to move the common bits from DT specific code to >>> driver core was in my TODO list as a prerequisite to adding ACPI >>> support to fw_devlink. This series gets that done. >>> >>> Tomi/Laurent/Grygorii, >>> >>> If you can test this series, that'd be great! >> >> I gave it a try, rebasing my branch from v5.9 to v5.10-rc2 first. On >> v5.10-rc2 the kernel dies when booting due to a deadlock (reported by >> lockdep, so hopefully not too hard to debug). *sigh*. Fortunately, it >> dies after the fw_devlink initialization, so I can still report results. > > Phew! For a sec I thought you said fw_devlink was causing a deadlock. > >> >> Before your series: >> >> [ 0.743065] cpuidle: using governor menu >> [ 13.350259] No ATAGs? >> >> With your series applied: >> >> [ 0.722670] cpuidle: using governor menu >> [ 1.135859] No ATAGs? >> >> That's a very clear improvement :-) > > Thanks for testing. Great to hear it's helping! > >> Tested-by: Laurent Pinchart > > I'll add it to my v2 series. I've tried your series on top of 521b619acdc8 Merge tag 'linux-kselftest-kunit-fixes-5.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest on am571x-idk Before: [ 0.049395] cpuidle: using governor menu [ 1.654766] audit: type=2000 audit(0.040:1): state=initialized audit_enabled=0 res=1 [ 2.315266] No ATAGs? [ 2.315317] hw-breakpoint: found 5 (+1 reserved) breakpoint and 4 watchpoint registers. [ 2.315327] hw-breakpoint: maximum watchpoint size is 8 bytes. ... [ 6.549595] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null) [ 6.557794] VFS: Mounted root (ext4 filesystem) on device 179:26. [ 6.574103] devtmpfs: mounted [ 6.577749] Freeing unused kernel memory: 1024K [ 6.582433] Run /sbin/init as init process after: [ 0.049223] cpuidle: using governor menu [ 0.095893] audit: type=2000 audit(0.040:1): state=initialized audit_enabled=0 res=1 [ 0.102958] No ATAGs? [ 0.103010] hw-breakpoint: found 5 (+1 reserved) breakpoint and 4 watchpoint registers. [ 0.103020] hw-breakpoint: maximum watchpoint size is 8 bytes. ... [ 3.518623] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null) [ 3.526822] VFS: Mounted root (ext4 filesystem) on device 179:26. [ 3.543128] devtmpfs: mounted [ 3.546781] Freeing unused kernel memory: 1024K [ 3.551463] Run /sbin/init as init process So, it's much better. Thank you. Tested-by: Grygorii Strashko -- Best regards, grygorii