From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751103AbdE2LHp (ORCPT ); Mon, 29 May 2017 07:07:45 -0400 Received: from mail-oi0-f68.google.com ([209.85.218.68]:35363 "EHLO mail-oi0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750965AbdE2LHo (ORCPT ); Mon, 29 May 2017 07:07:44 -0400 MIME-Version: 1.0 In-Reply-To: <1495774962-2981-1-git-send-email-jiada_wang@mentor.com> References: <1495774962-2981-1-git-send-email-jiada_wang@mentor.com> From: Fabio Estevam Date: Mon, 29 May 2017 08:07:42 -0300 Message-ID: Subject: Re: [PATCH linux-next v3 1/1] spi: imx: dynamic burst length adjust for PIO mode To: Jiada Wang Cc: Mark Brown , "linux-spi@vger.kernel.org" , linux-kernel , Sascha Hauer Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jiada, On Fri, May 26, 2017 at 2:02 AM, wrote: > From: Jiada Wang > > previously burst length (BURST_LENGTH) is always set to equal > to bits_per_word, causes a 10us gap between each word in > transfer, which significantly affects performance. > > This patch uses 32 bits transfer to simulate lower bits transfer, > and adjusts burst length runtimely to use biggeest burst length > as possible to reduce the gaps in transfer for PIO mode. Just curious: what is the performance gain you observe with this patch? From mboxrd@z Thu Jan 1 00:00:00 1970 From: Fabio Estevam Subject: Re: [PATCH linux-next v3 1/1] spi: imx: dynamic burst length adjust for PIO mode Date: Mon, 29 May 2017 08:07:42 -0300 Message-ID: References: <1495774962-2981-1-git-send-email-jiada_wang@mentor.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Mark Brown , "linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , linux-kernel , Sascha Hauer To: Jiada Wang Return-path: In-Reply-To: <1495774962-2981-1-git-send-email-jiada_wang-nmGgyN9QBj3QT0dZR+AlfA@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Hi Jiada, On Fri, May 26, 2017 at 2:02 AM, wrote: > From: Jiada Wang > > previously burst length (BURST_LENGTH) is always set to equal > to bits_per_word, causes a 10us gap between each word in > transfer, which significantly affects performance. > > This patch uses 32 bits transfer to simulate lower bits transfer, > and adjusts burst length runtimely to use biggeest burst length > as possible to reduce the gaps in transfer for PIO mode. Just curious: what is the performance gain you observe with this patch? -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html