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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 45B4AC433E0 for ; Wed, 15 Jul 2020 11:13:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 160E72071B for ; Wed, 15 Jul 2020 11:13:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594811601; bh=eydGT5vyj3DFkrTR3iGkM6VbuT/mY9iEwObflzBiA5M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=xFHtdaBFIqk3JSjP/W7UH/sOFawZgxEU+9cgRmom5S15mOcXA2Nwy0SfGx5gGx1iv c2Z7lvaadj2rvBp/A8CyR0wX60ZNcdX2GuaZ5x6SadUsLuo1S3QQd7t0UzM1wNAA7+ imWrpFrdh4g+QAPIL62Zyq17Yi8Fod+MEAsNl9Fg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726856AbgGOLNU (ORCPT ); Wed, 15 Jul 2020 07:13:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:51210 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726034AbgGOLNU (ORCPT ); Wed, 15 Jul 2020 07:13:20 -0400 Received: from localhost (unknown [122.171.202.192]) (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 21EC220658; Wed, 15 Jul 2020 11:13:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594811600; bh=eydGT5vyj3DFkrTR3iGkM6VbuT/mY9iEwObflzBiA5M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uRYxnG5OXQN4sijkPXo4JIQSHo3Qzo2kvJDps2v9dTJ0oqZ96Rea5oLMtoDrybZEf YHq/nhv6B7uhMyy7b5+bRM81cLS0YnTrkJlEiNxEi2qoxzVHKehGD6hMe8e5faj4Na wjf5BXMWyoj6kPiSBzLZn+xio+Bhagas8hBXFHcQ= Date: Wed, 15 Jul 2020 16:43:15 +0530 From: Vinod Koul To: Serge Semin Cc: Peter Ujfalusi , Serge Semin , Viresh Kumar , Dan Williams , Andy Shevchenko , Alexey Malahov , Thomas Bogendoerfer , Arnd Bergmann , Rob Herring , linux-mips@vger.kernel.org, devicetree@vger.kernel.org, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v7 04/11] dmaengine: Introduce max SG list entries capability Message-ID: <20200715111315.GK34333@vkoul-mobl> References: <20200709224550.15539-1-Sergey.Semin@baikalelectronics.ru> <20200709224550.15539-5-Sergey.Semin@baikalelectronics.ru> <20200710092738.z7zyywe46mp7uuf3@mobilestation> <427bc5c8-0325-bc25-8637-a7627bcac26f@ti.com> <20200710161445.t6eradkgt4terdr3@mobilestation> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200710161445.t6eradkgt4terdr3@mobilestation> Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 10-07-20, 19:14, Serge Semin wrote: > On Fri, Jul 10, 2020 at 02:51:33PM +0300, Peter Ujfalusi wrote: > > Since we should be able to handle longer lists and this is kind of a > > hint for clients that above this number of nents the list will be broken > > up to smaller 'bursts', which when traversing could cause latency. > > > > sg_chunk_len might be another candidate. > > Ok. We've got four candidates: > - max_sg_nents_burst > - max_sg_burst > - max_sg_chain > - sg_chunk_len > > @Vinod, @Andy, what do you think? So IIUC your hw supports single sg and in that you would like to publish the length of each chunk, is that correct? If so sg_chunk_len seems apt.. -- ~Vinod