From: Willy Tarreau <w@1wt.eu>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Andi Kleen" <andi@firstfloor.org>,
"Ray Lee" <ray-lk@madrabbit.org>, "Bo Brantén" <bosse@acc.umu.se>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Jesse Barnes" <jesse.barnes@intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: x86_64 ten times slower than i386
Date: Tue, 6 Nov 2007 20:40:09 +0100 [thread overview]
Message-ID: <20071106194009.GC1045@1wt.eu> (raw)
In-Reply-To: <472FC130.40605@zytor.com>
On Mon, Nov 05, 2007 at 05:19:44PM -0800, H. Peter Anvin wrote:
> Andi Kleen wrote:
> >>Jesse Barnes (cc:d) wrote a patch to address this, I think (x86: trim
> >>memory not covered by WB MTRRs), but as far as I can tell it hasn't
> >>been merged yet. System is Intel, 4gb of RAM.
> >
> >It wasn't merged because it broke booting on some systems.
> >Besides the memory would be still lost -- all it did was to automate
> >the "mem=XXXX" line.
>
> There really are only two ways to deal with this -- drop the memory
> (which should be automated, and a warning printed) or adjust the MTRRs.
> The problem is that at some point we run out of MTRRs, partially
> because they're masks instead of base/limit.
Just out of curiosity, what would be the problem if the MTRRs covered more
than the memory size ? For instance, instead of having 512 MB at 4G, why
not have 1G at 4G ?
regards,
Willy
next prev parent reply other threads:[~2007-11-06 19:40 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-03 12:31 x86_64 ten times slower than i386 Bo Brantén
2007-11-03 16:26 ` Matt Mackall
2007-11-03 22:38 ` Bo Brantén
2007-11-03 22:54 ` Matt Mackall
2007-11-03 23:30 ` H. Peter Anvin
2007-11-05 8:06 ` Joseph Fannin
2007-11-05 10:15 ` Bo Brantén
2007-11-05 16:00 ` Bo Brantén
2007-11-05 17:23 ` H. Peter Anvin
2007-11-05 18:46 ` Bo Brantén
2007-11-05 19:11 ` H. Peter Anvin
[not found] ` <2c0942db0711050832t5207ea8bib1f75e59e071ade2@mail.gmail.com>
2007-11-06 0:26 ` Andi Kleen
2007-11-06 1:19 ` H. Peter Anvin
2007-11-06 19:40 ` Willy Tarreau [this message]
2007-11-06 19:50 ` H. Peter Anvin
2007-11-06 19:53 ` Willy Tarreau
2007-11-07 18:38 ` Jesse Barnes
2007-11-10 13:41 ` Bo Brantén
2007-11-05 17:22 ` H. Peter Anvin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20071106194009.GC1045@1wt.eu \
--to=w@1wt.eu \
--cc=akpm@linux-foundation.org \
--cc=andi@firstfloor.org \
--cc=bosse@acc.umu.se \
--cc=hpa@zytor.com \
--cc=jesse.barnes@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=ray-lk@madrabbit.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox