From: Daniel Jacobowitz <dan@debian.org>
To: Ralf Baechle <ralf@linux-mips.org>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>,
Andrew Isaacson <adi@broadcom.com>,
linux-mips@linux-mips.org
Subject: Re: [patch 1/5] SiByte fixes for 2.6.12
Date: Mon, 3 Oct 2005 09:15:52 -0400 [thread overview]
Message-ID: <20051003131551.GA19075@nevyn.them.org> (raw)
In-Reply-To: <20051001092807.GD14463@linux-mips.org>
On Sat, Oct 01, 2005 at 10:28:07AM +0100, Ralf Baechle wrote:
> On Thu, Jun 23, 2005 at 12:01:57PM +0100, Maciej W. Rozycki wrote:
>
> > Well, the flag is not really to specify whether the common code is to be
> > used or not. It's about whether the TLB is like that of the R4k.
> > Actually it's always been a mystery for me why the common code cannot be
> > used for the SB1, but perhaps there is something specific that I could
> > only discover in that "SB-1 Core User Manual" that I yet have to see,
> > sigh...
> >
> > Of course if your TLB is indeed different from that of the R4k, then you
> > shouldn't be setting cp0.config.mt to 1 in the first place...
>
> The reason was primarily the tiny bit of extra performance because the
> SB1 doesn't need the hazard handling overhead. Also tlb-sb1 has a few
> changes that are needed to initialize a TLB in undefined state after
> powerup. That was needed to run Linux on firmware-less SB1 cores.
FYI, all I have is a piece of hard evidence: this patch was the
difference between not booting and booting for a Sentosa with CFE.
Which isn't firmwareless and isn't a tiny bit of extra performance
issue.
I'll try to give CVS HEAD a shot this week sometime.
--
Daniel Jacobowitz
CodeSourcery, LLC
next prev parent reply other threads:[~2005-10-03 13:16 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-06-22 23:00 [patch 0/5] SiByte fixes for 2.6.12 Andrew Isaacson
2005-06-22 23:00 ` [patch 1/5] " Andrew Isaacson
2005-06-23 11:01 ` Maciej W. Rozycki
2005-06-23 23:26 ` Andy Isaacson
2005-10-01 9:28 ` Ralf Baechle
2005-10-03 11:56 ` Maciej W. Rozycki
2005-10-03 12:50 ` Ralf Baechle
2005-10-03 13:15 ` Daniel Jacobowitz [this message]
2005-10-03 13:24 ` Ralf Baechle
2005-10-03 13:35 ` Maciej W. Rozycki
2005-10-01 10:15 ` Ralf Baechle
2006-01-16 15:48 ` Martin Michlmayr
2006-01-23 12:55 ` Martin Michlmayr
2005-06-22 23:01 ` [patch 2/5] " Andrew Isaacson
2005-06-22 23:01 ` [patch 3/5] " Andrew Isaacson
2005-06-23 11:07 ` Maciej W. Rozycki
2005-06-23 19:48 ` Andy Isaacson
2005-06-30 16:43 ` Maciej W. Rozycki
2005-07-18 17:19 ` Maciej W. Rozycki
2005-06-22 23:01 ` [patch 4/5] " Andrew Isaacson
2005-06-23 11:08 ` Maciej W. Rozycki
2005-06-23 14:49 ` Andy Isaacson
2005-06-23 15:11 ` Maciej W. Rozycki
2005-06-23 22:27 ` Andy Isaacson
2005-10-01 11:57 ` Ralf Baechle
2005-06-22 23:02 ` [patch 5/5] " Andrew Isaacson
2005-10-01 12:07 ` Ralf Baechle
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