Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751914AbdGZCR1 (ORCPT ); Tue, 25 Jul 2017 22:17:27 -0400 Received: from lelnx194.ext.ti.com ([198.47.27.80]:10081 "EHLO lelnx194.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751779AbdGZCQs (ORCPT ); Tue, 25 Jul 2017 22:16:48 -0400 From: Franklin S Cooper Jr To: , , , , , , , CC: Franklin S Cooper Jr Subject: [PATCH 1/3] ARM: dts: am335x-evm: Enable NAND dma prefetch by default Date: Tue, 25 Jul 2017 21:15:50 -0500 Message-ID: <20170726021552.19880-2-fcooper@ti.com> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20170726021552.19880-1-fcooper@ti.com> References: <20170726021552.19880-1-fcooper@ti.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1299 Lines: 32 Currently the default method of prefetch polled shows the highest possible read and write speed when minimal non NAND background activity is being done. But it is also very CPU intensive to reach these high speeds (CPU load of 99% via mtd performance tests). While DMA prefetch only uses 50% of the CPU to achieve around 23% less in top read and write performance. However, as the non NAND CPU load increases the read and write performance takes a large hit when using polled prefetch. Therefore, prefetch dma mode ends up outperforming prefetch polled in general "system level" test. So switch to using dma prefetch by default since it is likely what most users would prefer. Signed-off-by: Franklin S Cooper Jr --- arch/arm/boot/dts/am335x-evm.dts | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm/boot/dts/am335x-evm.dts b/arch/arm/boot/dts/am335x-evm.dts index 1c37a7c..ddd8975 100644 --- a/arch/arm/boot/dts/am335x-evm.dts +++ b/arch/arm/boot/dts/am335x-evm.dts @@ -531,6 +531,7 @@ interrupts = <0 IRQ_TYPE_NONE>, /* fifoevent */ <1 IRQ_TYPE_NONE>; /* termcount */ rb-gpios = <&gpmc 0 GPIO_ACTIVE_HIGH>; /* gpmc_wait0 */ + ti,nand-xfer-type = "prefetch-dma"; ti,nand-ecc-opt = "bch8"; ti,elm-id = <&elm>; nand-bus-width = <8>; -- 2.10.0