From: Ingo Molnar <mingo@elte.hu>
To: Jamie Lokier <jamie@shareable.org>
Cc: Andrew Morton <akpm@osdl.org>, Alexander Viro <viro@math.psu.edu>,
Linus Torvalds <torvalds@osdl.org>,
linux-kernel@vger.kernel.org
Subject: Re: open-scale-2.6.2-A0
Date: Wed, 11 Feb 2004 13:27:53 +0100 [thread overview]
Message-ID: <20040211122753.GA15129@elte.hu> (raw)
In-Reply-To: <20040211122031.GC15127@mail.shareable.org>
* Jamie Lokier <jamie@shareable.org> wrote:
> Ingo Molnar wrote:
> > i've attached an obvious scalability improvement for write()s. We in
> > essence used a system-global lock for every open(WRITE) - argh!
>
> I wonder if the "rip the second arsehole" is there for a reason.
these days i dont think the comment is justified.
> Does this scalability improvement make any measured difference in any
> conceivable application, or is it just making struct inode larger?
i've not added any new lock, i'm merely reusing the existing ->i_lock.
So there's no data or code bloat whatsoever.
one doesnt need any measurements to tell that a global cacheline
dirtying for every (most of the time completely unrelated) open(WRITE)
will hurt workloads that do that, especially on NUMA systems. I'd not be
surprised if it showed up in dbench/netbench.
Ingo
next prev parent reply other threads:[~2004-02-11 12:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-02-11 11:58 open-scale-2.6.2-A0 Ingo Molnar
2004-02-11 12:20 ` open-scale-2.6.2-A0 Jamie Lokier
2004-02-11 12:27 ` Ingo Molnar [this message]
2004-02-11 12:45 ` open-scale-2.6.2-A0 Jamie Lokier
2004-02-11 20:39 ` open-scale-2.6.2-A0 Andrew Morton
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