From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933113AbbJIQMR (ORCPT ); Fri, 9 Oct 2015 12:12:17 -0400 Received: from mga01.intel.com ([192.55.52.88]:52827 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757624AbbJIQMN (ORCPT ); Fri, 9 Oct 2015 12:12:13 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.17,658,1437462000"; d="scan'208";a="807373878" Date: Fri, 9 Oct 2015 17:12:09 +0100 From: Vinod Koul To: Rameshwar Prasad Sahu Cc: dan.j.williams@intel.com, dmaengine@vger.kernel.org, arnd@arndb.de, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, jcm@redhat.com, patches@apm.com Subject: Re: [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop Message-ID: <20151009161208.GJ3609@vkoul-mobl.iind.intel.com> References: <1444295217-3099-1-git-send-email-rsahu@apm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1444295217-3099-1-git-send-email-rsahu@apm.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 08, 2015 at 02:36:57PM +0530, Rameshwar Prasad Sahu wrote: > The DMA engine supports memory copy, RAID5 XOR, RAID6 PQ, and other > computations. But the bandwidth of the entire DMA engine is shared > among all channels. This patch re-configures operations availability > such that one can achieve maximum performance for XOR and PQ > computation by removing the memory offload operations. > > Signed-off-by: Rameshwar Prasad Sahu > --- > drivers/dma/xgene-dma.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c > index 8d57b1b..cd38022 100644 > --- a/drivers/dma/xgene-dma.c > +++ b/drivers/dma/xgene-dma.c > @@ -1707,7 +1707,6 @@ static void xgene_dma_set_caps(struct xgene_dma_chan *chan, > dma_cap_zero(dma_dev->cap_mask); > > /* Set DMA device capability */ > - dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask); > dma_cap_set(DMA_SG, dma_dev->cap_mask); This will not work. Still clients can invoke memcpy operation. You need to remove the callback -- ~Vinod