Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758326Ab3IBMqV (ORCPT ); Mon, 2 Sep 2013 08:46:21 -0400 Received: from merlin.infradead.org ([205.233.59.134]:40686 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756346Ab3IBMqT (ORCPT ); Mon, 2 Sep 2013 08:46:19 -0400 Subject: Re: [PATCH v4 0/6] dma: edma: Support scatter-lists of any length From: Vinod Koul To: Joel Fernandes Cc: vinod.koul@intel.com, Sekhar Nori , Matt Porter , Russell King , Sricharan R , Linux DaVinci Kernel List , Koen Kooi , Linux MMC List , Linux Kernel Mailing List , Franklin Cooper , Linux OMAP List , Linux ARM Kernel List In-Reply-To: <1377817545-18015-1-git-send-email-joelf@ti.com> References: <1377817545-18015-1-git-send-email-joelf@ti.com> Content-Type: text/plain; charset="UTF-8" Date: Mon, 02 Sep 2013 17:29:53 +0530 Message-ID: <1378123193.9854.1.camel@vkoul-udesk3> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2016 Lines: 42 On Thu, 2013-08-29 at 18:05 -0500, Joel Fernandes wrote: > The following series adds support to EDMA driver to enable DMA of > scatter-gather lists of arbitrary length, but still make use of only > a certain MAX number of slots at a time for a given channel. Thus > free-ing up the rest of the slots to other slaves/channels. With this > there is no need for slave drivers to query the EDMA driver about how > much is the MAX it can send at a time as done in [1]. Drivers can send > SG lists of any number of entries to DMA. Reference discussion at [2]. > > With this, all the patches for MMC and EDMA related to "sg limits" can be > dropped. > > Tested omap-aes and omap_hsmmc drivers with different MAX number of slots, > even just 1. In the case where it is 1, only 1-slot is used to DMA an > entire scatter list of arbitrary length. > Since this series touches EDMA private API code also shared with davinci-pcm, > playback of a 16-bit 44.1KHz audio file with davinci-pcm has been tested. > > Sample test run with 1 vs 16 (MAX number of slots/SG) in omap-aes driver: > MAX slots = 1: > (128 bit key, 8192 byte blocks): 1266 operations in 1 seconds (10371072 bytes) > MAX slots = 16: > (128 bit key, 8192 byte blocks): 1601 operations in 1 seconds (13115392 bytes) > > Note: For the above test, 8K buffer is mapped into SG list of size 2 so > only 2 slots are required. So beyond size 2, there will not be any noticeable > performance improvement. But above experiment just shows as proof of concept > that even using 1 slot is managed by just DMA'ing 1 SG entry at a time. much better series, thanks I think i am okay with this, if anyone has objections pls speak up. Also I need ack on the ARM patch 3/6 before I can carry this. -- Vinod Koul Intel Corp. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/