From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Ball Subject: Re: [PATCH] mmc: sdio: To use multiple scatter gather list Date: Sat, 17 Nov 2012 15:26:47 -0500 Message-ID: <87a9ug9drs.fsf@octavius.laptop.org> References: <001101cdb044$8565abf0$903103d0$%kim@samsung.com> <87d301q8kb.fsf@octavius.laptop.org> <001801cdbca7$0b12bc70$21383550$%kim@samsung.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from void.printf.net ([89.145.121.20]:39719 "EHLO void.printf.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752133Ab2KQU0z (ORCPT ); Sat, 17 Nov 2012 15:26:55 -0500 In-Reply-To: <001801cdbca7$0b12bc70$21383550$%kim@samsung.com> (Kyoungil Kim's message of "Wed, 07 Nov 2012 14:16:29 +0900") Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Kyoungil Kim Cc: linux-mmc@vger.kernel.org Hi, On Wed, Nov 07 2012, Kyoungil Kim wrote: > On Tue, Oct 30 2012, Chris Ball wrote: >> Hi, >> >> On Mon, Oct 22 2012, Kyoungil Kim wrote: >> > We used only single sg entry for SDIO transfer. >> > This chagne is to use multiple sg entry. >> > In case of dwmci, it support only up to 4KB size per single sg entry. >> > So if we want to transfer more than 4KB, we should send more than >> > 1 command. >> > This makes performance degradation for large data transfer. >> > >> > Signed-off-by: Kyoungil Kim >> >> Can you share the before/after benchmark on your controller, please? > > When we test before apply this patch, it takes around 335 us for > 5K(5120) bytes transfer with dwmci controller. > But when we test after apply this patch, it takes 242 us for 5K bytes. > So this patch makes around 38% performance improvement for 5K bytes transfer. > If the transfer size is bigger, then the performance improvement ratio > will be increased. Thanks, pushed to mmc-next for 3.8. - Chris. -- Chris Ball One Laptop Per Child