* Linux speed on sun4c
@ 2001-07-01 5:06 Aaron Lehmann
2001-07-01 6:36 ` David S. Miller
0 siblings, 1 reply; 5+ messages in thread
From: Aaron Lehmann @ 2001-07-01 5:06 UTC (permalink / raw)
To: linux-kernel, jakub, davem
NetBSD/Sparc's FAQ asserts:
Why is NetBSD so much faster than SparcLinux on sun4c (top)
The memory management hardware on sun4c machines (SPARCStation
1, 1+, 2, IPC, IPX, SLC, ELC and clones) is not handled particularly
well by Linux. Until Linux reworks their MMU code NetBSD will be very
much faster on this hardware.
Was there ever any truth to this statement? It seems to be light on
technical details. Have these purported issues ever been fixed?
I don't want to be scared into running NetBSD on my SparcStation 2 :D.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Linux speed on sun4c
2001-07-01 5:06 Linux speed on sun4c Aaron Lehmann
@ 2001-07-01 6:36 ` David S. Miller
2001-07-03 15:59 ` Guenter Millahn
2001-07-03 23:07 ` David S. Miller
0 siblings, 2 replies; 5+ messages in thread
From: David S. Miller @ 2001-07-01 6:36 UTC (permalink / raw)
To: Aaron Lehmann; +Cc: linux-kernel, jakub
Aaron Lehmann writes:
>
> NetBSD/Sparc's FAQ asserts:
>
> Why is NetBSD so much faster than SparcLinux on sun4c (top)
>
> The memory management hardware on sun4c machines (SPARCStation
> 1, 1+, 2, IPC, IPX, SLC, ELC and clones) is not handled particularly
> well by Linux. Until Linux reworks their MMU code NetBSD will be very
> much faster on this hardware.
>
> Was there ever any truth to this statement? It seems to be light on
> technical details. Have these purported issues ever been fixed?
>
> I don't want to be scared into running NetBSD on my SparcStation 2 :D.
It's totally true, use *BSD on your sun4c systems if top performance
is your desire. :-)
I know how to fix it but frankly I have no desire to work on
that platform any more.
Later,
David S. Miller
davem@redhat.com
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Linux speed on sun4c
2001-07-01 6:36 ` David S. Miller
@ 2001-07-03 15:59 ` Guenter Millahn
2001-07-03 23:07 ` David S. Miller
1 sibling, 0 replies; 5+ messages in thread
From: Guenter Millahn @ 2001-07-03 15:59 UTC (permalink / raw)
To: David S. Miller; +Cc: Aaron Lehmann, linux-kernel, jakub
On Sat, 30 Jun 2001, David S. Miller wrote:
> Aaron Lehmann writes:
> > NetBSD/Sparc's FAQ asserts:
> >
> > Why is NetBSD so much faster than SparcLinux on sun4c (top)
> >
> > The memory management hardware on sun4c machines (SPARCStation
> > 1, 1+, 2, IPC, IPX, SLC, ELC and clones) is not handled particularly
> > well by Linux. Until Linux reworks their MMU code NetBSD will be very
> > much faster on this hardware.
> >
> > Was there ever any truth to this statement? It seems to be light on
> > technical details. Have these purported issues ever been fixed?
> >
> > I don't want to be scared into running NetBSD on my SparcStation 2 :D.
What about OpenBSD? Same as NetBSD?
> It's totally true, use *BSD on your sun4c systems if top performance
> is your desire. :-)
>
> I know how to fix it but frankly I have no desire to work on
> that platform any more.
>
> Later,
> David S. Miller
> davem@redhat.com
David, can you publish your idea for a fix? Possibly anybody elese can make
the patch?
Thanks, Guenter
--
Dipl.-Ing. Guenter Millahn Brandenburg University of Technology
Systems, Network & DB Admin CS Dept / DB & IS Research Group
Voice: +49 (355) 69-2272/2700 P.O. Box: 10 13 44
Fax: +49 (355) 69-2766 D-03013 Cottbus GERMANY
"The real world is still far away from be led ad absurdum by the virtual
one." (Hal Faber, newsreel "What happened, what will be", 08/13/2000)
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Linux speed on sun4c
2001-07-01 6:36 ` David S. Miller
2001-07-03 15:59 ` Guenter Millahn
@ 2001-07-03 23:07 ` David S. Miller
2004-10-21 11:33 ` Nico Schottelius
1 sibling, 1 reply; 5+ messages in thread
From: David S. Miller @ 2001-07-03 23:07 UTC (permalink / raw)
To: Guenter Millahn; +Cc: Aaron Lehmann, linux-kernel, jakub
Guenter Millahn writes:
> David, can you publish your idea for a fix? Possibly anybody elese can make
> the patch?
Currently under Linux when a constext is recycled because a new
context is needed but all are in use, we basically toss all of
the MMU segments that context owned.
This is bogus because if the contexts are the limited resource
not the MMU segments themselves, we take a lot of false MMU
misses on each context switch for no reason.
The solution is to link the MMU segment software state structures
into the mm_struct. When an 'mm' reacquires a hw context, if any
MMU segments remain on the mm's list, just pluck them back into
the MMU.
Later,
David S. Miller
davem@redhat.com
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Linux speed on sun4c
2001-07-03 23:07 ` David S. Miller
@ 2004-10-21 11:33 ` Nico Schottelius
0 siblings, 0 replies; 5+ messages in thread
From: Nico Schottelius @ 2004-10-21 11:33 UTC (permalink / raw)
To: David S. Miller; +Cc: Guenter Millahn, Aaron Lehmann, linux-kernel, jakub
[-- Attachment #1: Type: text/plain, Size: 1290 bytes --]
Did anybody wrote a patch for that?
Nico
David S. Miller [Tue, Jul 03, 2001 at 04:07:16PM -0700]:
>
> Guenter Millahn writes:
> > David, can you publish your idea for a fix? Possibly anybody elese can make
> > the patch?
>
> Currently under Linux when a constext is recycled because a new
> context is needed but all are in use, we basically toss all of
> the MMU segments that context owned.
>
> This is bogus because if the contexts are the limited resource
> not the MMU segments themselves, we take a lot of false MMU
> misses on each context switch for no reason.
>
> The solution is to link the MMU segment software state structures
> into the mm_struct. When an 'mm' reacquires a hw context, if any
> MMU segments remain on the mm's list, just pluck them back into
> the MMU.
>
> Later,
> David S. Miller
> davem@redhat.com
> -
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--
Keep it simple & stupid, use what's available.
Please use pgp encryption: 8D0E 27A4 is my id.
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^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2004-10-21 11:39 UTC | newest]
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2001-07-01 5:06 Linux speed on sun4c Aaron Lehmann
2001-07-01 6:36 ` David S. Miller
2001-07-03 15:59 ` Guenter Millahn
2001-07-03 23:07 ` David S. Miller
2004-10-21 11:33 ` Nico Schottelius
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