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=-2.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham 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 1AAD0C43381 for ; Thu, 21 Feb 2019 21:40:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DF59320818 for ; Thu, 21 Feb 2019 21:40:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="V/+zw7sR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726417AbfBUVke (ORCPT ); Thu, 21 Feb 2019 16:40:34 -0500 Received: from mail-ed1-f68.google.com ([209.85.208.68]:42059 "EHLO mail-ed1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725802AbfBUVkd (ORCPT ); Thu, 21 Feb 2019 16:40:33 -0500 Received: by mail-ed1-f68.google.com with SMTP id j89so77330edb.9 for ; Thu, 21 Feb 2019 13:40:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:reply-to:references:mime-version :content-disposition:in-reply-to:user-agent; bh=U6umnKcmrpvh6pr+wrq8JquzEl64oVuliEyZreit8ho=; b=V/+zw7sRLrqtJxUPyvxNb8MKQsG2pYQGlbLh5rUxJQAR2/0Y0Wh7OzdkUXlN8ltfaD MCi7PFUTlM6tgdnda2uupDUq5TqIJnW/OwnvjE+ec5euqPHx24tHCKzzGJPeLcbNpEHZ BEex63cUbrVXiKGRWvC8pLmoCGzej0NDpsKi21cCTgdyIXcz4fqjFFXtv5E5o17yJMpq T4ptRaFBG0w4aiahaEqIf82ww2rWf7Xp94Tf3LRzLgA8B+CuZfETCSz24jBsVsW8hRoe LAWl61Oq9YaMwWELVIrp1gz2V1nZrpQPEISAoREKmN2+MDiNBJnVUormmg6z6SNBCFi7 3lkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:reply-to :references:mime-version:content-disposition:in-reply-to:user-agent; bh=U6umnKcmrpvh6pr+wrq8JquzEl64oVuliEyZreit8ho=; b=YrSzapP9+mNyCVgRFwKhQu9pL0QAmDTmlH9xOYqRn1Che2hJlvqq5zTQyDaIsgaiNB IW4XVHZvMxD6ZMOrSjlgAvECPMWjeBTfHx//7c17z5VYm0f4YNRYVZCh8yRF15BRvG2y llpdDSbQ2r8j0xN+CJSAJ0Q/Uo/bjQJ1kHW7ZrZNL1gkgPmyytoniZbIqHI+200s2LoR jRqbeylKFXfB5I3wyAraeM5LUtCnLQmAgEABAZr7XkVn6Bg6nPEqK3TGfPMMkat3ozDa BF6gVwl7lxVjOTMSlwYpPBkjVkiuxnlCKEAbQFEbNE10fYFW+tEsMu4J2K4vzFokkw/T d0qw== X-Gm-Message-State: AHQUAubtXhTzLZjBhYQRS2Wxb4c6nk7rlbDe6w+S5hh1JFW/dryWNW6U VMwMmv/hluWJS6vqH22wRBs= X-Google-Smtp-Source: AHgI3Ibb7+mt/4l+lgojp/7/oTKoJrf98ow7LaCXjFPIfShGaFH43RfU1zrj7DaqtU+40xAnBfG1iw== X-Received: by 2002:a50:86ce:: with SMTP id 14mr504217edu.33.1550785231958; Thu, 21 Feb 2019 13:40:31 -0800 (PST) Received: from localhost ([185.92.221.13]) by smtp.gmail.com with ESMTPSA id e21sm467edb.27.2019.02.21.13.40.30 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 21 Feb 2019 13:40:30 -0800 (PST) Date: Thu, 21 Feb 2019 21:40:30 +0000 From: Wei Yang To: Greg Kroah-Hartman Cc: Wei Yang , "Huang, Ying" , kernel test robot , Stephen Rothwell , "Rafael J. Wysocki" , lkp@01.org, LKML Subject: Re: [LKP] [driver core] 570d020012: will-it-scale.per_thread_ops -12.2% regression Message-ID: <20190221214030.niwvh3xjlioi3myd@master> Reply-To: Wei Yang References: <20190218075442.GI29177@shao2-debian> <20190219005945.GA16734@richard> <20190219121904.GA24103@kroah.com> <20190221031049.GE28258@shao2-debian> <20190221071023.GA28637@kroah.com> <8736oh1uf5.fsf@yhuang-dev.intel.com> <20190221073510.GA17369@kroah.com> <87va1dzgpj.fsf@yhuang-dev.intel.com> <20190221083926.GA7834@richard> <20190221091217.GA18701@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190221091217.GA18701@kroah.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 21, 2019 at 10:12:17AM +0100, Greg Kroah-Hartman wrote: >On Thu, Feb 21, 2019 at 04:39:27PM +0800, Wei Yang wrote: >> >>> I don't think this is an issues of struct device. As you said, struct >> >>> device isn't access much during test. Struct device may share slab page >> >>> with some other data structures (signal related, or fd related (as in >> >>> some other test cases)), so that the alignment of these data structures >> >>> are affected, so caused the performance regression. >> >> >> >> But allocation of a structure should always be "properly" aligned, no >> >> matter what something else did in the system as that is what kmalloc >> >> ensures. If not, then we have problems in our memory allocator :) >> >> >> >> So something is odd here, but I don't think that is it... >> > >> >If all these data structure are allocated with kmalloc() instead of >> >kmem_cache_alloc(), then my guessing above seems incorrect ... >> > >> >> Seems we don't have special kmem_cache for device and device_private. > >Nor do we need one :) > >Remember, 'struct device' is included inside lots of other structures >already, it is not very often created "on its own." > You are right, I get your point. >thanks, > >greg k-h -- Wei Yang Help you, Help me