From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753347AbaGJW0y (ORCPT ); Thu, 10 Jul 2014 18:26:54 -0400 Received: from seketeli.net ([94.23.218.202]:52708 "EHLO ms.seketeli.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751649AbaGJW0w (ORCPT ); Thu, 10 Jul 2014 18:26:52 -0400 From: Apelete Seketeli To: Chris Ball , Ulf Hansson , H Hartley Sweeten , Lars-Peter Clausen , Wei Yongjun , Alex Smith , Laurent Pinchart , linux-mmc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Subject: [PATCH v3] Use DMA for data transfers in JZ4740 MMC driver Date: Fri, 11 Jul 2014 00:27:25 +0200 Message-Id: <1405031246-16365-1-git-send-email-apelete@seketeli.net> X-Mailer: git-send-email 1.7.10.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, MMC driver for JZ4740 SoC is currently relying on PIO mode only for data transfers. The patch that comes as a follow-up of this message allows the use of DMA for data transfers. Changes since v2: - declare sg_len member of struct jz4740_mmc_host as int instead of unsigned int. Changes since v1: - remove blank line added by mistake in jz_mmc_prepare_data_transfer(). According to the following DMA vs PIO benchmarks there seems to be a slight improvement in transfer speed with the Ben NanoNote booting from SD card, while load average seems to be roughly on par: * With DMA: Test cases | root@BenNanoNote:/# uptime | root@BenNanoNote:/# time zcat root/fedora-16.iso.gz > /dev/null && uptime -----------|---------------------------------------------------------------------------------------------------------------------------------- Test run 1 | 00:20:55 up 1 min, load average: 1.26, 0.42, 0.14 | 00:26:10 up 6 min, load average: 2.89, 1.94, 0.89 Test run 2 | 00:30:22 up 1 min, load average: 1.16, 0.38, 0.13 | 00:35:34 up 6 min, load average: 2.68, 1.86, 0.85 Test run 3 | 00:39:56 up 1 min, load average: 1.16, 0.38, 0.13 | 00:45:06 up 6 min, load average: 2.57, 1.76, 0.81 -----------|---------------------------------------------------------------------------------------------------------------------------------- Average | 1 min, load average: 1.19, 0.39, 0.13 | 6 min, load average: 2.71, 1.85, 0.85 * With PIO: Test cases | root@BenNanoNote:/# uptime | root@BenNanoNote:/# time zcat root/fedora-16.iso.gz > /dev/null && uptime ---------------------------------------------------------------------------------------------------------------------------------------------- Test run 1 | 00:50:47 up 1 min, load average: 1.42, 0.49, 0.17 | 00:56:52 up 7 min, load average: 2.47, 2.00, 0.98 Test run 2 | 01:00:19 up 1 min, load average: 1.21, 0.39, 0.14 | 01:06:29 up 7 min, load average: 2.45, 1.96, 0.96 Test run 3 | 01:11:27 up 1 min, load average: 1.15, 0.36, 0.12 | 01:17:33 up 7 min, load average: 2.63, 2.01, 0.97 -----------|---------------------------------------------------------------------------------------------------------------------------------- Average | 1 min, load average: 1.26, 0.41, 0.14 | 7 min, load average: 2.52, 1.99, 0.97 DMA tranfers performance might be further improved with a latter patch by taking advantage of the asynchronous request capability of the MMC framework. Changes were rebased on top of linux master branch, built and tested successfully. The following changes since commit cd3de83: Linux 3.16-rc4 are available in the git repository at: git://git.seketeli.net/~apelete/linux.git jz4740-mmc-dma Apelete Seketeli (1): mmc: jz4740: add dma infrastructure for data transfers drivers/mmc/host/jz4740_mmc.c | 172 +++++++++++++++++++++++++++++++++++++++-- 1 file changed, 164 insertions(+), 8 deletions(-) -- 1.7.10.4