On Fri, 1 Feb 2002, Peter Wemm wrote:
- AMD write cache allocation due to speculative writes being cancelled and
then written back later vs no cache snooping on AGP regions. I'm somewhat
perplexed about this issue, there's lots of conflicting info going around,
a good deal of it which
Narvi wrote:
Speculative writes can only happen to pages in the TLB (so you don't get
speculative TLB misses and replacements), not having a large amount of 4M
pages around in the TLB means that addresses covered by these can't
possibly be involved in speculative writes.
I personaly
On Mon, 4 Feb 2002, Terry Lambert wrote:
Narvi wrote:
Speculative writes can only happen to pages in the TLB (so you don't get
speculative TLB misses and replacements), not having a large amount of 4M
pages around in the TLB means that addresses covered by these can't
possibly be
Narvi wrote:
I wasn't aware that I was contradicting Peter 8-)
Sorry; looked like it to me... 8-).
It may even well be possible to get different results with aligned vs.
misaligned reads and writes, or a proper mix thereof. It may be possible
to build a model to track down the what is
Glendon Gross wrote:
That's right, guys! This is FreeBSD after all... so Mr. Lambert is
entitled to charge 10K for that bugfix code if he wants. In fact he is
Free to do so. But it's a little pricy for me, although perhaps not for
AMD if it means they can fix their cache-paging problems!
Terry Lambert wrote:
Glendon Gross wrote:
That's right, guys! This is FreeBSD after all... so Mr. Lambert is
entitled to charge 10K for that bugfix code if he wants. In fact he is
Free to do so. But it's a little pricy for me, although perhaps not for
AMD if it means they can fix
Peter Wemm wrote:
I'm a little confused as to which bugs are which that we're talking
about now. Which is the one that you're trying to sell the info for?
I'm not really trying to sell the fix; it's that I'm not
willing to give it away when it's no benefit to do so; I'd
need a bribe. Kind of
On Thu, 31 Jan 2002, Jason Evans wrote:
On Wed, Jan 30, 2002 at 11:14:48PM +0100, Gérard Roudier wrote:
Linux can be fixed, but the useless writes of the existing Athlons from
the very fast cache to the relatively very slow memory cannot. And all
Athlon users may well pay this penalty
On Thu, 31 Jan 2002, Terry Lambert wrote:
Cameron, Frank wrote:
From what was posted on the linux-kernel list the problem is the OS
doing the wrong thing not the hardware. I originally asked the
question (albeit not worded as clearly as I should have) because if
Microsoft and Linux
On Thu, Jan 31, 2002 at 09:32:48PM +0100, Gérard Roudier wrote:
On Thu, 31 Jan 2002, Jason Evans wrote:
On Wed, Jan 30, 2002 at 11:14:48PM +0100, Gérard Roudier wrote:
Linux can be fixed, but the useless writes of the existing Athlons from
the very fast cache to the relatively
On Fri, 1 Feb 2002, Erik Trulsson wrote:
On Thu, Jan 31, 2002 at 09:32:48PM +0100, Gérard Roudier wrote:
On Thu, 31 Jan 2002, Jason Evans wrote:
On Wed, Jan 30, 2002 at 11:14:48PM +0100, Gérard Roudier wrote:
Linux can be fixed, but the useless writes of the existing
Erik Trulsson wrote:
The Athlon rewriting same value to cacheable memory under the knees of
programmers looks a severe issue to me if it is true. Not only AGP memory
can be affected. What about SMP, MMIO (if some cacheable mapping exists),
etc...?
I am not familiar with the acronym
Kenneth Culver wrote:
Actually FreeBSD does make use of them, but in a way that doesn't cause a
problem.
There's actually a seperate TLB bug, but FreeBSD doesn't
trigger that one, either (Linux can tickle it, when there
are certain specific circumstances met).
$10,000, and I'll tell you how
There's actually a seperate TLB bug, but FreeBSD doesn't
trigger that one, either (Linux can tickle it, when there
are certain specific circumstances met).
Well, I think I know what you're talking about, linux allocates agpgart
memory without setting a non-cacheable bit, and then the agp card
Message-
From: Kenneth Culver [mailto:[EMAIL PROTECTED]]
Sent: Thursday, January 31, 2002 10:42 AM
To: Terry Lambert
Cc: David Malone; Cameron, Frank; '[EMAIL PROTECTED]';
'[EMAIL PROTECTED]'
Subject: Re: AMD AGP Bug
There's actually a seperate TLB bug, but FreeBSD doesn't
trigger
PROTECTED]'
Subject: Re: AMD AGP Bug
There's actually a seperate TLB bug, but FreeBSD doesn't
trigger that one, either (Linux can tickle it, when there
are certain specific circumstances met).
Well, I think I know what you're talking about, linux
allocates agpgart
memory without
Lambert
Cc: David Malone; Cameron, Frank; '[EMAIL PROTECTED]';
'[EMAIL PROTECTED]'
Subject: Re: AMD AGP Bug
There's actually a seperate TLB bug, but FreeBSD doesn't
trigger that one, either (Linux can tickle it, when there
are certain specific circumstances met
Kenneth Culver wrote:
There's actually a seperate TLB bug, but FreeBSD doesn't
trigger that one, either (Linux can tickle it, when there
are certain specific circumstances met).
Well, I think I know what you're talking about, linux allocates agpgart
memory without setting a non-cacheable
Cameron, Frank wrote:
From what was posted on the linux-kernel list the problem is the OS
doing the wrong thing not the hardware. I originally asked the
question (albeit not worded as clearly as I should have) because if
Microsoft and Linux programmers made the same mistake, might
FreeBSD
.
-Original Message-
From: Kenneth Culver [mailto:[EMAIL PROTECTED]]
Sent: Thursday, January 31, 2002 10:42 AM
To: Terry Lambert
Cc: David Malone; Cameron, Frank; '[EMAIL PROTECTED]';
'[EMAIL PROTECTED]'
Subject: Re: AMD AGP Bug
There's actually a seperate
On Wed, Jan 30, 2002 at 11:14:48PM +0100, Gérard Roudier wrote:
Linux can be fixed, but the useless writes of the existing Athlons from
the very fast cache to the relatively very slow memory cannot. And all
Athlon users may well pay this penalty under any OS... unless we want to
disable
I was under the impression that they were writing into the cache not out
of it... I really need to read that article again :-D
Ken
On Thu, 31 Jan 2002, Jason Evans wrote:
On Wed, Jan 30, 2002 at 11:14:48PM +0100, Gérard Roudier wrote:
Linux can be fixed, but the useless writes of the
Terry Lambert wrote:
Cameron, Frank wrote:
From what was posted on the linux-kernel list the problem is the OS
doing the wrong thing not the hardware. I originally asked the
question (albeit not worded as clearly as I should have) because if
Microsoft and Linux programmers made the same
Cc: David Malone; Cameron, Frank; '[EMAIL PROTECTED]';
'[EMAIL PROTECTED]'
Subject: Re: AMD AGP Bug
There's actually a seperate TLB bug, but FreeBSD doesn't
trigger that one, either (Linux can tickle it, when there
are certain specific circumstances met).
Well, I think
Peter Wemm wrote:
We need to use the PAT cpu_features feature. This gives us 8 page attribute
modes instead of simple no-cache / writethrough flags. We can (and must)
control more carefully the speculative hardware prefetch, for example.
I've been thinking about this with the pmap revamp
Peter Wemm wrote:
No. FreeBSD does not make active use of 4M pages for anything
other than the initial kernel text and data, which is obvious,
if you look at /sys/i386/machdep.c.
Actually, it is obvious if you actually do look at the pmap.c that we *do*
use 4MB pages for device
On Thu, Jan 31, 2002 at 07:22:25PM -0800, Terry Lambert wrote:
Peter Wemm wrote:
We need to use the PAT cpu_features feature. This gives us 8 page attribute
modes instead of simple no-cache / writethrough flags. We can (and must)
control more carefully the speculative hardware prefetch,
Steve Kargl wrote:
This sounds cool.
Do you have references to the page attribute stuff? The
books I have here don't discuss it; the only thing I see
are 3 bits (9,10,11) that are available in the PDE and
PTE?
Well, twice in this thread you've offered info for
$1. I'm sure
On Wed, Jan 30, 2002 at 12:13:07PM -0500, Cameron, Frank wrote:
Has this issue been addressed in FreeBSD:
http://www.geocrawler.com/lists/3/Linux/35/175/7626960/
http://slashdot.org/article.pl?sid=02/01/24/1910227mode=thread
This is believed not to have any impact on FreeBSD because FreeBSD
You should check the archives of the FreeBSD mailing lists before sending
a message to 4 of the lists. This quiestion has been answered several
times on the FreeBSD lists. The answer is that this isn't even really an
AMD AGP bug, it's a bug in the way linux handles mapping it's AGP memory.
Actually FreeBSD does make use of them, but in a way that doesn't cause a
problem.
Ken
On Wed, 30 Jan 2002, David Malone wrote:
On Wed, Jan 30, 2002 at 12:13:07PM -0500, Cameron, Frank wrote:
Has this issue been addressed in FreeBSD:
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