From: Ingo Molnar <mingo@elte.hu>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ravikiran G Thirumalai <kiran@scalex86.org>,
Frederik Deweerdt <frederik.deweerdt@xprog.eu>,
andi@firstfloor.org, tglx@linutronix.de, hpa@zytor.com,
linux-kernel@vger.kernel.org
Subject: Re: [patch] tlb flush_data: replace per_cpu with an array
Date: Tue, 13 Jan 2009 13:33:17 +0100 [thread overview]
Message-ID: <20090113123317.GA29926@elte.hu> (raw)
In-Reply-To: <1231848016.442.112.camel@twins>
* Peter Zijlstra <peterz@infradead.org> wrote:
> > - char pad[SMP_CACHE_BYTES];
> > -} ____cacheline_aligned;
> > + char pad[X86_INTERNODE_CACHE_BYTES];
> > +} ____cacheline_internodealigned_in_smp;
>
> That will make the below array 8*4096 bytes for VSMP, which pushes the
> limit for memory savings up to 256 cpus.
VSMP is a clustering solution (default-disabled) that pushes
L1_CACHE_BYTES to 4096 bytes (4K). That is an extremely large alignment
that pushes up the BSS size ten-fold (!), so no generic Linux distribution
enables it. 32K compared to 9MB bloat caused by 4K cachelines is a drop in
the ocean.
Ingo
next prev parent reply other threads:[~2009-01-13 12:33 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-12 21:35 [patch] tlb flush_data: replace per_cpu with an array Frederik Deweerdt
2009-01-12 21:46 ` Ingo Molnar
2009-01-12 21:57 ` Andi Kleen
2009-01-12 22:10 ` Frederik Deweerdt
2009-01-12 22:32 ` Andi Kleen
2009-01-12 22:50 ` Ingo Molnar
2009-01-12 22:40 ` Ingo Molnar
2009-01-12 22:59 ` H. Peter Anvin
2009-01-13 2:43 ` Andi Kleen
2009-01-13 12:28 ` Ingo Molnar
2009-01-12 22:34 ` Ravikiran G Thirumalai
2009-01-12 23:00 ` Ingo Molnar
2009-01-12 23:09 ` Ingo Molnar
2009-01-13 2:14 ` Ravikiran G Thirumalai
2009-01-13 12:00 ` Peter Zijlstra
2009-01-13 12:33 ` Ingo Molnar [this message]
2009-01-13 18:13 ` Ravikiran G Thirumalai
2009-01-13 18:34 ` Ingo Molnar
2009-01-13 18:42 ` Ravikiran G Thirumalai
2009-01-14 7:31 ` Ingo Molnar
2009-01-15 7:15 ` Ravikiran G Thirumalai
2009-01-14 9:08 ` Andi Kleen
2009-01-14 14:41 ` Frederik Deweerdt
2009-01-14 15:20 ` Andi Kleen
2009-01-14 15:10 ` Frederik Deweerdt
2009-01-12 22:54 ` Mike Travis
2009-01-12 23:51 ` Frederik Deweerdt
2009-01-12 23:57 ` Mike Travis
2009-01-13 0:01 ` Ingo Molnar
2009-01-13 3:36 ` Andi Kleen
2009-01-13 12:14 ` Ingo Molnar
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