From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grygorii Strashko Subject: Re: cyclictest versus custom SPI based system Date: Fri, 15 Jan 2016 13:31:43 +0200 Message-ID: <5698D89F.9020203@ti.com> References: <5696992E.703@bristot.me> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit To: Julio Cruz Barroso , Daniel Bristot de Oliveira , "linux-rt-users@vger.kernel.org" Return-path: Received: from bear.ext.ti.com ([192.94.94.41]:33629 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751095AbcAOLbu (ORCPT ); Fri, 15 Jan 2016 06:31:50 -0500 In-Reply-To: Sender: linux-rt-users-owner@vger.kernel.org List-ID: Hi Julio, On 01/14/2016 10:11 AM, Julio Cruz Barroso wrote: > > I changed the policy:priority as you suggested and the system is stable now!! I will prepare an application to measure the latency with some loads during long periods (but this is another thing). > > For reference, in my case (iMX6), the priority adjustment was done at spi.c (master->rt). A patch was suggested to implement this by device tree but other opinion said that this sound like a Linux specific feature/implementation [4]. Anyways, this is another issue. > Just curios, is it possible for you to achieve the same results from User space using chrt/taskset utils? (without Kernel modification). For example, I can see below processes on my system: 184 root 0 SW [spi32766] and our QSPI driver don't use IRQs. > [4] Patch to implement SPI RT in device tree: http://www.spinics.net/lists/arm-kernel/msg348713.html > -- regards, -grygorii