From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-f172.google.com ([209.85.217.172]:36828 "EHLO mail-lb0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754866AbcDAXFp (ORCPT ); Fri, 1 Apr 2016 19:05:45 -0400 Received: by mail-lb0-f172.google.com with SMTP id qe11so81165866lbc.3 for ; Fri, 01 Apr 2016 16:05:44 -0700 (PDT) Subject: Re: [PATCH v3 09/11] i2c: rcar: revoke START request early To: Wolfram Sang References: <1447948611-2615-1-git-send-email-wsa@the-dreams.de> <1447948611-2615-10-git-send-email-wsa@the-dreams.de> <56FD9080.4090203@cogentembedded.com> <20160331224838.GA7381@katana> <56FED245.4010503@cogentembedded.com> <20160401201415.GA25936@katana> Cc: linux-i2c@vger.kernel.org, linux-sh@vger.kernel.org, Magnus Damm , Simon Horman , Laurent Pinchart , Geert Uytterhoeven , Kuninori Morimoto , Yoshihiro Shimoda , "stable@vger.kernel.org" , "linux-renesas-soc@vger.kernel.org" From: Sergei Shtylyov Message-ID: <56FEFEC4.6010401@cogentembedded.com> Date: Sat, 2 Apr 2016 02:05:40 +0300 MIME-Version: 1.0 In-Reply-To: <20160401201415.GA25936@katana> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: On 04/01/2016 11:14 PM, Wolfram Sang wrote: > >>> IIRC my tests showed that if you don't remove >>> the spinlocks (patch 4), the interrupt latency will already be too high >>> again. >> >> Thank you for the valuable info! > > Oh, and add patch 6 to it. The context switches are a major problem in > this. Thanks again! I ended up backporting all the patches up to #9. Not sure it'd be acceptable for the -stable kernels since there's a lot of refactors involved... MBR, Sergei