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 133B5C7618B for ; Wed, 24 Jul 2019 13:38:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D1B0322ADB for ; Wed, 24 Jul 2019 13:38:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563975496; bh=1YIiARjBCZhAYRSdWpXHpVJxvWd/TEuDaQWmESH5Fg4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=zL/PclMr51LSlOk5Nafnu6FBKvqJ3+VJuPpHn6fuust9C9BAWlJ6W9oxqHfmTXERt BdZ9Yr8ni+9MQkQiIHQ4m/EqkhFFk32bfDhsxvfok0Q+qHFxLcn+3gyDAMZBkjSZ7e eVz0eEJQAsOZleS4kKonYCd8AbYRV0xPvcb1vqDU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726631AbfGXNiQ (ORCPT ); Wed, 24 Jul 2019 09:38:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:60768 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725826AbfGXNiQ (ORCPT ); Wed, 24 Jul 2019 09:38:16 -0400 Received: from localhost (173-25-83-245.client.mchsi.com [173.25.83.245]) (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 9A5012190F; Wed, 24 Jul 2019 13:38:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563975495; bh=1YIiARjBCZhAYRSdWpXHpVJxvWd/TEuDaQWmESH5Fg4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=sMud2GYZAqqp7c/0dZ33BRTYXSHhSIMuO3NxzLXpt9GeTndrtnt6qszPKZHsfgNAb MR14gjNG2NUII5pV8pVS9MGbX6ixLJP/6uANJR06qsCs26VCLUHGqgR6hyy2X1hDom pRisnQEmuuAiGf4TlZy9VkiI2oFPvaj9VFcJO+hY= Date: Wed, 24 Jul 2019 08:38:14 -0500 From: Bjorn Helgaas To: Nicholas Johnson Cc: Logan Gunthorpe , Benjamin Herrenschmidt , Mika Westerberg , "linux-pci@vger.kernel.org" Subject: Re: Possible PCI Regression Linux 5.3-rc1 Message-ID: <20190724133814.GA194025@google.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Jul 24, 2019 at 12:54:00PM +0000, Nicholas Johnson wrote: > Hi all, > > I was just rebasing my patches for linux 5.3-rc1 and noticed a possible > regression that shows on both of my machines. It is also reproducible > with the unmodified Ubuntu mainline kernel, downloadable at [1]. > > Running the lspci command takes 1-3 seconds with 5.3-rc1 (rather than an > imperceivable amount of time). Booting with pci.dyndbg does not reveal > why. > > $ uname -r > 5.3.0-050300rc1-generic > $ time lspci -vt 1>/dev/null > > real 0m2.321s > user 0m0.026s > sys 0m0.000s > > If none of you are aware of this or what is causing it, I will submit a > bug report to Bugzilla. I wasn't aware of this; thanks for reporting it! I wasn't able to reproduce this in qemu. Can you play with "strace -r lspci -vt" and the like? Maybe try "lspci -n" to see if it's related to looking up the names?