From: Alex Pankratov <ap@swapped.cc>
To: Andi Kleen <ak@suse.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] [2.6] [2/2] hlist: remove IFs from hlist functions
Date: Wed, 11 Feb 2004 08:48:44 -0800 [thread overview]
Message-ID: <402A5CEC.2030603@swapped.cc> (raw)
In-Reply-To: <p73y8ra5721.fsf@nielsen.suse.de>
Andi Kleen wrote:
> Alex Pankratov <ap@swapped.cc> writes:
>
>>
>>No, because its 'pprev' field *is* getting modified.
>
> I didn't notice this before, sorry. But this could end up
> being a scalability problem on big SMP systems. Even though
> the cache line of this is never read it will bounce all the
> time between all CPUs using hlists and add considerably
> latency and cross node traffic. Remember Linux is supposed
> to run well on 128 CPU machines now.
That's a bit above my head. How does this potential latency
compare to the speed up due to not having CMPs ? My cycle
counting skills are a bit dusty :)
>
> Maybe you can make it UP only, but I'm still not sure it's
> worth it.
>
Sorry, I didn't the 'UP' part.
next prev parent reply other threads:[~2004-02-11 16:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4029CB7E.4030003@swapped.cc.suse.lists.linux.kernel>
[not found] ` <4029CF24.1070307@osdl.org.suse.lists.linux.kernel>
[not found] ` <4029D2D5.7070504@swapped.cc.suse.lists.linux.kernel>
2004-02-11 8:55 ` [PATCH] [2.6] [2/2] hlist: remove IFs from hlist functions Andi Kleen
2004-02-11 16:48 ` Alex Pankratov [this message]
2004-02-14 18:59 ` Andi Kleen
2004-02-12 4:42 ` Alex Pankratov
2004-02-14 19:43 ` Andi Kleen
2004-02-11 6:28 Alex Pankratov
2004-02-11 6:43 ` Stephen Hemminger
2004-02-11 6:59 ` Alex Pankratov
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