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=-5.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 CB797C4338F for ; Thu, 29 Jul 2021 16:13:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B3F7760F5C for ; Thu, 29 Jul 2021 16:13:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229614AbhG2QNM (ORCPT ); Thu, 29 Jul 2021 12:13:12 -0400 Received: from mail-pj1-f43.google.com ([209.85.216.43]:37867 "EHLO mail-pj1-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229485AbhG2QNL (ORCPT ); Thu, 29 Jul 2021 12:13:11 -0400 Received: by mail-pj1-f43.google.com with SMTP id a4-20020a17090aa504b0290176a0d2b67aso16415408pjq.2 for ; Thu, 29 Jul 2021 09:13:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=dgl5to4+5D05PZ0Bohqff8F4DJgwO18K8mRXqCAuzcQ=; b=C7k+3Nfdy+znPSq14wNn6bx452NqJux+J9h7pUFUFUZ55ZcAckU0usVSfiHYfCWR6Q 3jTQ5S+LDVmMwQV4BKMmbK4xGANSW8EB5A1L3GN7HHu3+N24/lzcE4p+DyY85MgDt/Vr on6HUoIjQFy0+ZjDYVP04r/dQi9v05Vglcl6p2eZJrcGpW/X3C2p2bLLsThuAA6AslCL vuzcQvwOw/g9brUxglLeE924Y8PoROJTabDTH5KYpgdhOsmtuPRLPcXU92Fg6vEuA9qi nH5MRNUitjECRkgNGV3MKh5QcRNuJaH0Juaz6ZqKb8POJRnvSbf12hakkNgC//trVCuz C+/w== X-Gm-Message-State: AOAM5316xj43TSuUwq7Po++Np5xfiSAR+oMT5ql8d8CkvuqmiW+83Cvo 8UCnqHqzwBK5En/Gp5dCPik= X-Google-Smtp-Source: ABdhPJwFxInCj/QGCLLYsMf+WcQASFMG4gJ/7dkM3+WXWIslxReJlOz0Ayycp74A2tXKRyHREgMvXw== X-Received: by 2002:a17:902:da82:b029:12b:ac76:204a with SMTP id j2-20020a170902da82b029012bac76204amr5312382plx.56.1627575187104; Thu, 29 Jul 2021 09:13:07 -0700 (PDT) Received: from bvanassche-linux.mtv.corp.google.com ([2620:15c:211:1:3328:5f8d:f6e2:85ea]) by smtp.gmail.com with ESMTPSA id y5sm4269454pfn.87.2021.07.29.09.13.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 29 Jul 2021 09:13:06 -0700 (PDT) Subject: Re: [PATCH v3 11/18] scsi: ufs: Revert "Utilize Transfer Request List Completion Notification Register" From: Bart Van Assche To: Bean Huo , "Martin K . Petersen" Cc: linux-scsi@vger.kernel.org, Jaegeuk Kim , Adrian Hunter , Stanley Chu , Can Guo , Asutosh Das , Avri Altman , "James E.J. Bottomley" , Matthias Brugger , Bean Huo , Kiwoong Kim , Keoseong Park , Caleb Connolly , "Gustavo A. R. Silva" References: <20210722033439.26550-1-bvanassche@acm.org> <20210722033439.26550-12-bvanassche@acm.org> Message-ID: <46e6aa0e-8845-317a-026e-86423969c2b6@acm.org> Date: Thu, 29 Jul 2021 09:13:04 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On 7/29/21 9:10 AM, Bart Van Assche wrote: > On 7/29/21 1:03 AM, Bean Huo wrote: >> How did you compare the performance gain/loss after reverting this >> commit? > > I measured the performance impact of patches 11 and 12 combined. In a 4 > KB read IOPS test I see that these two patches combined improve > performance by 1%. This illustrates that the two MMIO accesses of the > UTRLCNR register are slower than the single MMIO access of the doorbell > register. A correction: I wanted to refer to the combination of patches 11 and 13 instead of 11 and 12. Bart.