From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxim Levitsky Subject: RE: PATA IDE is slower in newer versions of kernel Date: Sat, 18 Sep 2010 21:22:54 +0200 Message-ID: <1284837774.12425.1.camel@localhost.localdomain> References: <00d401cb55f7$33a78210$9af68630$@com> <20100917154732.330c4b1b@varda> <010901cb5754$ae6735a0$0b35a0e0$@com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:59506 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757087Ab0IRTXA (ORCPT ); Sat, 18 Sep 2010 15:23:00 -0400 In-Reply-To: <010901cb5754$ae6735a0$0b35a0e0$@com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Joshua Hintze Cc: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org On Sat, 2010-09-18 at 11:12 -0600, Joshua Hintze wrote: > Some updated information. I created a screen capture of what I am seeing. First is the logic analyzer when the newer linux kernel is writing slow to the PATA port. > > http://i56.tinypic.com/oqhrug.png > > Notice in the above link how there is a lot of activating and then large gaps of no activity. After about 9 mS the STOP line is strobed a few times and then DMARQ finally returns to normal operating. The link below shows the picture of an old 2.6.10 kernel where write speeds are much faster. > > http://i51.tinypic.com/a9wiur.png > > In the above image notice how the wait time is considerable less 100's of microseconds before the stop lines get strobed. > > I'm dedicated to continue working on the problem, I just need to advice from the linux community. I've tried different I/O schedulers such as noop and anticipatory and I'm studying the ide-dma code but still lost to where this is happening. > > Thanks! > Maybe you can just bisect this? Just a general advice, I don't know ide subsystem at all. Best regards, Maxim Levitsky