From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by ozlabs.org (Postfix) with ESMTP id D4A3C2C009B for ; Mon, 20 Jan 2014 19:45:28 +1100 (EST) Date: Mon, 20 Jan 2014 13:13:49 +0530 From: Vinod Koul To: hongbo.zhang@freescale.com Subject: Re: [PATCH] DMA: Freescale: change BWC from 256 bytes to 1024 bytes Message-ID: <20140120074349.GH26823@intel.com> References: <1389852653-8806-1-git-send-email-hongbo.zhang@freescale.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1389852653-8806-1-git-send-email-hongbo.zhang@freescale.com> Cc: linux-kernel@vger.kernel.org, scottwood@freescale.com, dmaengine@vger.kernel.org, dan.j.williams@intel.com, linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Jan 16, 2014 at 02:10:53PM +0800, hongbo.zhang@freescale.com wrote: > From: Hongbo Zhang > > Freescale DMA has a feature of BandWidth Control (ab. BWC), which is currently > 256 bytes and should be changed to 1024 bytes for best DMA throughput. > Changing BWC from 256 to 1024 will improve DMA performance much, in cases > whatever one channel is running or multi channels are running simultanously, > large or small buffers are copied. And this change doesn't impact memory > access performance remarkably, lmbench tests show that for some cases the > memory performance are decreased very slightly, while the others are even > better. > Tested on T4240. Applied, thanks -- ~Vinod