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Message-Id: <20100918124750.393a64a8.rdunlap@xenotime.net>
Date: Sat, 18 Sep 2010 12:47:50 -0700
From: Randy Dunlap <rdunlap@...otime.net>
To: "Joshua Hintze" <joshh@...ar.com>
Cc: "'Maxim Levitsky'" <maximlevitsky@...il.com>,
<linux-kernel@...r.kernel.org>, <linux-ide@...r.kernel.org>
Subject: Re: PATA IDE is slower in newer versions of kernel
On Sat, 18 Sep 2010 13:43:40 -0600 Joshua Hintze wrote:
> Thanks,
>
> I'm not sure what you mean by bisect, other than just the definition of the word. I am breaking this problem down adding printks etc. I think I'm finally beginng to understand how this works :)
>
http://www.kernel.org/pub/software/scm/git/docs/git-bisect.html
http://www.kernel.org/pub/software/scm/git/docs/user-manual.html#using-bisect
>
>
> -----Original Message-----
> From: linux-ide-owner@...r.kernel.org [mailto:linux-ide-owner@...r.kernel.org] On Behalf Of Maxim Levitsky
> Sent: Saturday, September 18, 2010 1:23 PM
> To: Joshua Hintze
> Cc: linux-kernel@...r.kernel.org; linux-ide@...r.kernel.org
> Subject: RE: PATA IDE is slower in newer versions of kernel
>
> 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
---
~Randy
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