Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756608AbaGIWiF (ORCPT ); Wed, 9 Jul 2014 18:38:05 -0400 Received: from exprod5og109.obsmtp.com ([64.18.0.188]:53431 "HELO exprod5og109.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751235AbaGIWiD (ORCPT ); Wed, 9 Jul 2014 18:38:03 -0400 MIME-Version: 1.0 In-Reply-To: <20140624.223442.1599243407487139839.davem@davemloft.net> References: <1403306296-26198-1-git-send-email-isubramanian@apm.com> <1403306296-26198-5-git-send-email-isubramanian@apm.com> <20140624.223442.1599243407487139839.davem@davemloft.net> Date: Wed, 9 Jul 2014 15:38:00 -0700 Message-ID: Subject: Re: [PATCH v8 4/4] drivers: net: Add APM X-Gene SoC ethernet driver support. From: Iyappan Subramanian To: David Miller Cc: netdev , "devicetree@vger.kernel.org" , Greg KH , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "jcm@redhat.com" , patches , Ravi Patel , Keyur Chudgar Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 24, 2014 at 10:34 PM, David Miller wrote: > From: Iyappan Subramanian > Date: Fri, 20 Jun 2014 16:18:16 -0700 > >> This patch adds network driver for APM X-Gene SoC ethernet. >> >> Signed-off-by: Iyappan Subramanian >> Signed-off-by: Ravi Patel >> Signed-off-by: Keyur Chudgar > > I really don't like how you handle the hardware descriptors in this > driver. > > You copy back and forth between a software format and the hardware > format. That's extremely wasteful and will hurt performance. > > Just use the raw format throughout, you can extract the fields when > you need them. I agree and I will fix this and resubmit the patches. > > You also make two passes when building a hardware descriptor: > > 1) write the values > 2) endian swap > > This means you make three memory accesses on every 64-bit word > in every descriptor you setup, this is really inefficient. > > You should just byte swap them in-situ as you build the raw > descriptors. -- 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/