From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Nick Piggin <npiggin@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hugh@veritas.com>,
Linux Memory Management List <linux-mm@kvack.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [patch] i386: avoid expensive ppro ordering workaround for default 686 kernels
Date: Wed, 2 Jan 2008 13:44:33 +0000 [thread overview]
Message-ID: <20080102134433.6ca82011@the-village.bc.nu> (raw)
In-Reply-To: <20080102110225.GA16154@wotan.suse.de>
> Take a different approach: after this patch, we just disable all but one CPU on those
> systems, and print a warning. Also printed is a suggestion for a new CONFIG option that
> can be enabled for the previous behaviour.
How does that help. The processor isn't the only bus master.
Maybe this works as a SuSE specific convenience solution aligned to
your particular build pattern but it isn't the right solution for
upstream IMHO.
We should either
- re-order the assumed processor generations supported to put VIA C3/C5
above Preventium Pro
- fix the gcc or gcc settings not to generate invalid cmov instructions
on 686. cmov is slower on all the modern processors anyway.
And you change the assumption that 586 < 686 < PPro < PII < PIII ...
to 586 < 686 < PPro < C3 < PII < ...
then selecting VIA C3 support will get you a kernel with the properties
all the distribution vendors want for their higher end mainstream kernel -
"runs on modern systems".
Alan
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next prev parent reply other threads:[~2008-01-02 13:44 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-18 1:26 [patch] mm: fix PageUptodate memory ordering bug Nick Piggin
2007-12-22 8:57 ` Andrew Morton
2007-12-22 12:14 ` Hugh Dickins
2007-12-23 6:54 ` Nick Piggin
2007-12-23 5:57 ` Nick Piggin
2007-12-23 6:32 ` Andrew Morton
2007-12-23 7:15 ` Nick Piggin
2007-12-23 7:29 ` Andrew Morton
2007-12-23 9:14 ` Nick Piggin
2007-12-23 9:28 ` Andrew Morton
2007-12-23 16:02 ` Andi Kleen
2007-12-30 16:33 ` Ingo Molnar
2008-01-01 23:26 ` Nick Piggin
2008-01-02 21:01 ` Andi Kleen
2008-01-03 3:32 ` Nick Piggin
2008-01-03 13:08 ` Andi Kleen
2007-12-23 17:22 ` Linus Torvalds
2007-12-23 21:35 ` Nick Piggin
2007-12-23 22:41 ` Nick Piggin
2008-01-01 23:41 ` Alan Cox
2008-01-02 11:02 ` [patch] i386: avoid expensive ppro ordering workaround for default 686 kernels Nick Piggin
2008-01-02 13:44 ` Alan Cox [this message]
2008-01-03 4:17 ` Nick Piggin
2008-01-03 14:23 ` Alan Cox
2008-01-03 20:20 ` Benjamin Herrenschmidt
2008-01-03 22:23 ` Alan Cox
2008-01-03 23:10 ` Nick Piggin
2008-01-04 16:27 ` Alan Cox
2008-01-07 0:12 ` Nick Piggin
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