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=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 2A4ACC4338F for ; Thu, 29 Jul 2021 08:05:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0C28C61054 for ; Thu, 29 Jul 2021 08:05:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234913AbhG2IFJ (ORCPT ); Thu, 29 Jul 2021 04:05:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234713AbhG2IEc (ORCPT ); Thu, 29 Jul 2021 04:04:32 -0400 Received: from mail-wm1-x32e.google.com (mail-wm1-x32e.google.com [IPv6:2a00:1450:4864:20::32e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38E92C061757 for ; Thu, 29 Jul 2021 01:03:58 -0700 (PDT) Received: by mail-wm1-x32e.google.com with SMTP id b128so3108619wmb.4 for ; Thu, 29 Jul 2021 01:03:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:subject:from:to:cc:date:in-reply-to:references :user-agent:mime-version:content-transfer-encoding; bh=ORak2jPPspmIKNt/Iq+PZt7iiPn3UMvDGcZJaEhAWp8=; b=PKgigtTQWzq/FEMNIKVGlyWq0R7PhVAkfRQ0gQyun84YFGSkpTL85C9UTPIPkulkG2 AZmQpG0xmUzrfYBC8xGDx6wKQ2KnskekCF6k91sTAndeAaU+vStkHgf9tQzI37EPSRU2 D8XC42EwkoAwqdd9XwmqcKQ1y5fT0Mc/ldI5CSn/KDTjb2IfRFphe1JDstIVEoQk7ssY 7VJ51HCIdgEPH63dNS4VefV3cHbNjBOGm33QYdu4QSaUnxiZJiWRuFWZY1KeLta0V/9N qABdpUG9WfuE+ObxqgVYfIIgPFgTz6lB58/+BJRYCdk3/bz7EgGx9lAAatbi2E6AzOnJ YJyQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=ORak2jPPspmIKNt/Iq+PZt7iiPn3UMvDGcZJaEhAWp8=; b=c9tNRqW8AFZiFMlBV9/99+osDiJTnxG71KxAD2caSE91dmCwV0Hj7uBgd2BOU0wU+V jMQNKMqQzOhaAYoyyEPu7Iwd3+e3XB9ks3OHNNE33Lu8Y4IThqdjPNiy5ZFqb47/acIT 4kukpAe0Di+wcafJdrvpaQS7IXHPax6y/Wvt0U0jcVH5MMxPvZ+5lZMXTGDbfikUAWPV rwsm9RqUr/leoh7URktk2ca19MpTGw8LIurRdQHLDLHbKU89eKuWrHBOGgc/U42yZSQf 8r0yxW1zJwtkY+XJKXL0hOKz5sjGJfgN8rh7fVZFDh/dRi+ugTB58AyivXGKisI63pM1 EqnQ== X-Gm-Message-State: AOAM532W6Ju7v1ZuN4inQsWauqQGsEnl3+BIuVUW9waVFY3RCWH6CkcQ +BYoBfxXP+hZZzro6wIS+WU= X-Google-Smtp-Source: ABdhPJyy03+UyykHKpnJVeVL8u+E5UKvMM3qRCrqm6olwug9VtBJpmhwMcatzWqfa79HYkMVKT1jcQ== X-Received: by 2002:a1c:9814:: with SMTP id a20mr3334433wme.158.1627545836891; Thu, 29 Jul 2021 01:03:56 -0700 (PDT) Received: from ubuntu-laptop (ip5f5bfdd7.dynamic.kabel-deutschland.de. [95.91.253.215]) by smtp.googlemail.com with ESMTPSA id b14sm2608592wrm.43.2021.07.29.01.03.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Jul 2021 01:03:56 -0700 (PDT) Message-ID: Subject: Re: [PATCH v3 11/18] scsi: ufs: Revert "Utilize Transfer Request List Completion Notification Register" From: Bean Huo To: Bart Van Assche , "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" Date: Thu, 29 Jul 2021 10:03:54 +0200 In-Reply-To: <20210722033439.26550-12-bvanassche@acm.org> References: <20210722033439.26550-1-bvanassche@acm.org> <20210722033439.26550-12-bvanassche@acm.org> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.36.5-0ubuntu1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On Wed, 2021-07-21 at 20:34 -0700, Bart Van Assche wrote: > Using the UTRLCNR register involves two MMIO accesses in the hot path > while > > using the doorbell register only involves a single MMIO access. Since > MMIO > > accesses take time, do not use the UTRLCNR register. The spinlock > contention > > on the SCSI host lock that is reintroduced by this patch will be > addressed > > by a later patch. > > > > This reverts commit 6f7151729647e58ac7c522081255fd0c07b38105. Bart, This commit is the key change in "Optimize host lock on TR send/compl paths and utilize UTRLCNR" https://patchwork.kernel.org/project/linux-scsi/cover/1621845419-14194-1-git-send-email-cang@codeaurora.org/. How did you compare the performance gain/loss after reverting this commit? Kind regards, Bean