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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 5D837C4740C for ; Mon, 9 Sep 2019 12:45:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2FD3E218DE for ; Mon, 9 Sep 2019 12:45:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728629AbfIIMpC (ORCPT ); Mon, 9 Sep 2019 08:45:02 -0400 Received: from mga01.intel.com ([192.55.52.88]:31239 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726008AbfIIMpC (ORCPT ); Mon, 9 Sep 2019 08:45:02 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 09 Sep 2019 05:45:02 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,484,1559545200"; d="scan'208";a="383963542" Received: from ahunter-desktop.fi.intel.com (HELO [10.237.72.66]) ([10.237.72.66]) by fmsmga005.fm.intel.com with ESMTP; 09 Sep 2019 05:44:58 -0700 Subject: Re: [PATCH 2/4] mmc: Add virtual command queue support To: Baolin Wang Cc: Ulf Hansson , riteshh@codeaurora.org, asutoshd@codeaurora.org, Orson Zhai , Chunyan Zhang , Arnd Bergmann , Linus Walleij , Vincent Guittot , linux-mmc , LKML References: <14599f7165f23db2bf7b71a2596e808e2bc2056c.1567740135.git.baolin.wang@linaro.org> <3bcd69fd-2f8e-9b87-7292-4b0b1aa5be78@intel.com> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: <3d83db18-7e80-944c-fc4b-244249c71bbf@intel.com> Date: Mon, 9 Sep 2019 15:43:48 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/09/19 3:16 PM, Baolin Wang wrote: > Hi Adrian, > > On Mon, 9 Sep 2019 at 20:02, Adrian Hunter wrote: >> >> On 6/09/19 6:52 AM, Baolin Wang wrote: >>> Now the MMC read/write stack will always wait for previous request is >>> completed by mmc_blk_rw_wait(), before sending a new request to hardware, >>> or queue a work to complete request, that will bring context switching >>> overhead, especially for high I/O per second rates, to affect the IO >>> performance. >>> >>> Thus this patch introduces virtual command queue interface, which is >>> similar with the hardware command queue engine's idea, that can remove >>> the context switching. >> >> CQHCI is a hardware interface for eMMC's that support command queuing. What >> you are doing is a software issue queue, unrelated to CQHCI. I think you > > Yes. > >> should avoid all reference to CQHCI i.e. call it something else. > > Since its process is similar with CQHCI and re-use the CQHCI's > interfaces, I called it virtual command queue. I am not sure what else > name is better, any thoughts? VCQHCI? Thanks. What about swq for software queue. Maybe Ulf can suggest something?