From: "Jeff V. Merkey" <jmerkey@timpanogas.org>
To: David Lang <david.lang@digitalinsight.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: 2.2.18Pre Lan Performance Rocks!
Date: Tue, 31 Oct 2000 15:57:23 -0700 [thread overview]
Message-ID: <39FF4E53.481B5EE2@timpanogas.org> (raw)
In-Reply-To: <Pine.LNX.4.21.0010311442120.6447-100000@dlang.diginsite.com>
David Lang wrote:
>
> -----BEGIN PGP SIGNED MESSAGE-----
>
> Jeff, one other thing. Linux is not x86 hand-crafted assembler, it's
> capable of running on many platforms. are you planning on giving up this
> capability or hand crafting the kernel for each chip?
>
> Linux on x86 is nice (and I do use it a lot) but one of the things that
> makes it so useful is that when you do outgrow what youcan do on a x86
> platform you cna move to a more powerful platform without having to change
> to a different OS.
How about a NetWare like NOS with all the application support of Linux?
I think a lot of people will love it. Novell's largest customers have
told me they want to see it, and would deploy it. I do believe there's
a market for such a beast. A very lucrative one...
Jeff
>
> David Lang
>
> On Tue, 31 Oct 2000,
> Jeff V. Merkey wrote:
>
> > Date: Tue, 31 Oct 2000 15:45:45 -0700
> > From: Jeff V. Merkey <jmerkey@timpanogas.org>
> > To: Andi Kleen <ak@suse.de>, mingo@elte.hu, Pavel Machek <pavel@suse.cz>,
> > linux-kernel@vger.kernel.org
> > Subject: Re: 2.2.18Pre Lan Performance Rocks!
> >
> >
> >
> > One more optimization it has. NetWare never "calls" functions in the
> > kernel. There's a template of register assignments in between kernel
> > modules that's very strict (esi contains a WTD head, edi has the target
> > thread, etc.) and all function calls are jumps in a linear space.
> > layout of all functions are 16 bytes aligned for speed, and all
> > arguments in kernel are passed via registers. It's a level of
> > optimization no C compiler does -- all of it was done by hand, and most
> > function s in fast paths are layed out in 512 byte chunks to increases
> > speed. Stack memory activity in the NetWare kernel is almost
> > non-existent in almost all of the "fast paths"
> >
> > Jeff
> >
> > "Jeff V. Merkey" wrote:
> > >
> > > A "context" is usually assued to be a "stack". The simplest of all
> > > context switches
> > > is:
> > >
> > > mov x, esp
> > > mov esp, y
> > >
> > > A context switch can be as short as two instructions, or as big as a TSS
> > > with CR3 hardware switching,
> > >
> > > i.e.
> > >
> > > ltr ax
> > > jmp task_gate
> > >
> > > (500 clocks later)
> > >
> > > ts->eip gets exec'd
> > >
> > > you can also have a context switch that does an int X where X is a gate
> > > or TSS.
> > >
> > > you can also have a context switch (like linux) that does
> > >
> > > mov x, esp
> > > mov esp, y
> > > mov z, CR3
> > > mov CR3, w
> > >
> > > etc.
> > >
> > > In NetWare, a context switch is an in-line assembly language macro that
> > > is 2 instructions long for a stack switch and 4 instructions for a CR3
> > > reload -- this is a lot shorter than Linux.
> > > Only EBX, EBP, ESI, and EDI are saved and this is never done in the
> > > kernel, but is a natural
> > > affect of the Watcom C compiler. There's also strict rules about
> > > register assignments that re enforced between assembler modules in
> > > NetWare to reduce the overhead of a context switch. The code path is
> > > very complex in NetWare, and priorities and all this stuff exists, but
> > > these code paths are segragated so these types of checks only happen
> > > once in a while and check a pre-calc'd "scoreboard" that is read only
> > > across processors and updated and recal'd by a timer every 18 ticks.
> > >
> > > Jeff
> > >
> > >
> > >
> > > Andi Kleen wrote:
> > > >
> > > > On Tue, Oct 31, 2000 at 02:52:11PM -0700, Jeff V. Merkey wrote:
> > > > > The numbers don't lie. You know where the code is. You notice that
> > > > > there is a version of
> > > > > the kernel hand coded in assembly language. You'l also noticed that
> > > > > it's SMP and takes ZERO LOCKS during context switching, in fact, most of
> > > > > the design is completely lockless.
> > > >
> > > > I suspect most of the confusion in this thread comes because you seem to
> > > > use a different definition of context switch than Ingo and others. Could
> > > > you explain what you exactly mean with a context switch ?
> > > >
> > > > -Andi
> > -
> > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> > the body of a message to majordomo@vger.kernel.org
> > Please read the FAQ at http://www.tux.org/lkml/
> >
>
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-
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Please read the FAQ at http://www.tux.org/lkml/
next prev parent reply other threads:[~2000-10-31 23:01 UTC|newest]
Thread overview: 152+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-10-29 23:19 2.2.18Pre Lan Performance Rocks! Jeff V. Merkey
[not found] ` <E13q2R7-0006S7-00@the-village.bc.nu>
2000-10-30 1:35 ` Jeff V. Merkey
2000-10-30 6:47 ` Andi Kleen
2000-10-30 6:58 ` Jeff V. Merkey
2000-10-30 7:08 ` Andi Kleen
2000-10-30 7:16 ` Jeff V. Merkey
2000-10-30 7:38 ` Andi Kleen
2000-10-30 8:04 ` Jeff V. Merkey
2000-10-30 8:16 ` Andi Kleen
2000-10-30 12:47 ` Alan Cox
2000-10-30 12:50 ` Andi Kleen
2000-10-30 8:26 ` Ingo Molnar
2000-10-30 7:20 ` Jeff V. Merkey
2000-10-30 8:39 ` Ingo Molnar
2000-10-30 8:08 ` Jeff V. Merkey
2000-10-30 9:52 ` Ingo Molnar
2000-10-30 8:55 ` Jeff V. Merkey
2000-10-30 10:13 ` Ingo Molnar
2000-10-30 9:11 ` Jeff V. Merkey
2000-10-30 10:41 ` Ingo Molnar
2000-10-30 9:33 ` Jeff V. Merkey
2000-10-30 10:56 ` Ingo Molnar
2000-10-30 9:45 ` Jeff V. Merkey
2000-10-30 11:04 ` Ingo Molnar
2000-10-30 9:56 ` Jeff V. Merkey
2000-10-30 11:13 ` Ingo Molnar
2000-10-30 10:08 ` Jeff V. Merkey
2000-10-30 17:41 ` Andrea Arcangeli
2000-10-30 17:58 ` Chris Evans
2000-10-30 18:01 ` Jeff V. Merkey
2000-10-30 18:21 ` Andrea Arcangeli
2000-10-30 17:59 ` Jeff V. Merkey
2000-10-31 8:08 ` Ingo Molnar
2000-10-31 20:04 ` Jeff V. Merkey
2000-10-30 19:11 ` Dan Hollis
2000-10-31 18:59 ` Pavel Machek
2000-10-30 10:27 ` Ingo Molnar
2000-10-30 9:20 ` Jeff V. Merkey
2000-10-30 10:44 ` Ingo Molnar
2000-10-30 9:38 ` Jeff V. Merkey
2000-10-30 11:01 ` Ingo Molnar
2000-10-30 9:54 ` Jeff V. Merkey
2000-10-30 11:12 ` Ingo Molnar
2000-10-30 10:06 ` Jeff V. Merkey
2000-10-30 10:56 ` john slee
2000-10-30 18:04 ` Jeff V. Merkey
2000-10-30 11:31 ` Ingo Molnar
2000-10-30 12:57 ` Alan Cox
2000-10-30 17:55 ` Jeff V. Merkey
2000-10-30 18:34 ` Alan Cox
2000-10-30 21:17 ` Jeff V. Merkey
2000-10-31 9:25 ` Erik Andersen
2000-10-31 18:50 ` Pavel Machek
2000-10-31 20:06 ` Jeff V. Merkey
2000-10-31 20:13 ` Jeff V. Merkey
2000-10-31 21:31 ` Ingo Molnar
2000-10-31 21:56 ` Ingo Molnar
2000-10-31 21:57 ` Jeff V. Merkey
2000-11-01 0:27 ` Ingo Molnar
2000-10-31 23:18 ` Jeff V. Merkey
2000-11-01 0:47 ` Ingo Molnar
2000-11-01 0:56 ` Davide Libenzi
[not found] ` <20001102031546.B10806@cerebro.laendle>
[not found] ` <20001101212835.A2425@vger.timpanogas.org>
[not found] ` <20001102043332.A27126@fuji.laendle>
[not found] ` <3A0195DA.DDEBAC51@timpanogas.org>
[not found] ` <20001102194323.D2790@cerebro.laendle>
[not found] ` <3A01CBB5.48C3094A@timpanogas.org>
[not found] ` <20001102214903.F2790@cerebro.laendle>
[not found] ` <3A01E71A.778BD898@timpanogas.org>
[not found] ` <20001102232210.H2790@cerebro.laendle>
[not found] ` <3A01ECD2.76DE10FF@timpanogas.org>
2000-11-02 22:46 ` Jeff V. Merkey
2000-11-03 0:12 ` Davide Libenzi
2000-11-02 23:00 ` Jeff V. Merkey
2000-10-31 21:34 ` Ingo Molnar
2000-10-31 21:52 ` Jeff V. Merkey
2000-10-31 22:05 ` Andi Kleen
2000-10-31 22:23 ` Jeff V. Merkey
2000-10-31 22:45 ` Jeff V. Merkey
2000-10-31 22:44 ` David Lang
2000-10-31 22:57 ` Jeff V. Merkey [this message]
2000-10-31 22:52 ` David Lang
2000-10-31 23:02 ` Alan Cox
2000-10-31 23:03 ` Jeff V. Merkey
2000-11-01 0:08 ` Ingo Molnar
2000-10-31 22:59 ` Jeff V. Merkey
2000-11-01 2:30 ` Horst von Brand
2000-10-31 23:05 ` Richard B. Johnson
2000-10-31 23:14 ` Jeff V. Merkey
2000-11-01 0:32 ` Ingo Molnar
2000-10-31 23:23 ` Jeff V. Merkey
2000-11-01 0:55 ` Ingo Molnar
2000-10-31 23:54 ` Ingo Molnar
2000-10-31 22:47 ` Jeff V. Merkey
2000-10-31 22:56 ` Larry McVoy
2000-10-31 22:55 ` Jeff V. Merkey
2000-11-01 0:10 ` Ingo Molnar
2000-11-01 5:38 ` Daniel Phillips
2000-11-03 6:42 ` Daniel Phillips
2000-10-31 22:59 ` Michael H. Warfield
2000-10-31 23:12 ` Ingo Molnar
2000-10-31 22:28 ` Jeff V. Merkey
2000-11-01 5:01 ` Peter Samuelson
2000-11-01 5:09 ` Larry McVoy
2000-11-01 5:20 ` Peter Samuelson
2000-10-30 10:50 ` Ingo Molnar
2000-10-30 9:40 ` Jeff V. Merkey
2000-10-30 23:26 ` David Woodhouse
2000-10-30 23:49 ` Jeff V. Merkey
2000-10-31 23:34 ` Roger Larsson
2000-10-31 15:18 ` Reto Baettig
2000-10-31 20:26 ` Alan Cox
2000-10-31 15:30 ` Reto Baettig
2000-10-31 20:37 ` Alan Cox
2000-10-31 20:48 ` Jesse Pollard
2000-10-31 20:58 ` Alan Cox
2000-11-01 1:33 ` Horst von Brand
2000-11-01 3:42 ` Jesse Pollard
2000-11-01 13:26 ` Horst von Brand
2000-10-31 21:43 ` Jeff V. Merkey
2000-10-31 21:50 ` Jeff V. Merkey
2000-10-31 20:36 ` Rik van Riel
2000-10-31 15:47 ` Reto Baettig
2000-10-31 21:05 ` Rik van Riel
2000-10-31 21:33 ` Jeff V. Merkey
2000-10-31 21:48 ` Rik van Riel
2000-10-31 16:54 ` Reto Baettig
2000-10-31 21:58 ` Rik van Riel
2000-10-31 21:53 ` Jeff V. Merkey
[not found] <200010300823.BAA19834@vger.timpanogas.org>
2000-10-30 8:36 ` Jeff V. Merkey
2000-10-31 21:44 Jeff V. Merkey
2000-10-31 21:36 ` Paul Menage
2000-10-31 21:44 ` David S. Miller
2000-10-31 23:21 ` Matti Aarnio
2000-10-31 23:39 ` David Weinehall
2000-10-31 22:05 ` Larry McVoy
2000-10-31 22:15 ` Jeff V. Merkey
2000-10-31 22:27 ` Larry McVoy
2000-10-31 22:38 ` Jeff V. Merkey
2000-10-31 22:48 ` Rik van Riel
2000-10-31 22:50 ` Jeff V. Merkey
2000-10-31 22:49 ` Larry McVoy
2000-10-31 22:53 ` Jeff V. Merkey
2000-10-31 23:15 ` Nathan Paul Simons
2000-10-31 23:20 ` Jeff V. Merkey
2000-11-01 0:00 ` Michael H. Warfield
2000-11-01 0:07 ` Alan Cox
2000-11-01 0:13 ` Michael H. Warfield
2000-11-01 1:30 ` Andrea Arcangeli
[not found] ` <20001031183809.C9733@.timpanogas.org>
2000-11-01 15:41 ` Andrea Arcangeli
2000-11-01 17:25 ` Jeff V. Merkey
2000-11-01 17:35 ` Jeff V. Merkey
2000-11-01 18:07 ` Andrea Arcangeli
2000-11-01 18:34 ` Jeff V. Merkey
2000-11-01 21:13 ` Daniel Phillips
2000-11-01 21:32 ` Jeff V. Merkey
2000-11-01 11:13 ` David Woodhouse
2000-11-01 15:00 ` Andrea Arcangeli
2000-11-01 9:51 ` Anton Altaparmakov
2000-11-01 17:28 ` Jeff V. Merkey
2000-11-02 21:58 ` Anton Altaparmakov
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