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From: Andrew Morton <akpm@osdl.org>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: davem@davemloft.net, anton@samba.org, linux-arch@vger.kernel.org,
	Peter.Keilty@hp.com
Subject: Re: Global spinlock vs local bit spin locks
Date: Thu, 16 Jun 2005 21:45:18 -0700	[thread overview]
Message-ID: <20050616214518.7df96d8a.akpm@osdl.org> (raw)
In-Reply-To: <1118982092.5261.44.camel@npiggin-nld.site>

Nick Piggin <nickpiggin@yahoo.com.au> wrote:
>
> Peter Keilty is running into some scalability problems with buffer
>  head based IO. There are a couple of global spinlocks in the buffer
>  completion path, and they're showing up on 16-way IA64 systems.

Well in -mm these spinlocks are hashed and the performance is good.  But
it's a bit dorky.  So we don't _have_ to go with the bit_spin_lock()
approach.  But bit_spin_lock() is nicer.

The reason why I went with a hashed lock is that I have memories of being
beaten up over suckiness of bit_spin_lock().  But I'm now wondering who was
beating me up, and why ;)

  reply	other threads:[~2005-06-17  4:45 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-06-17  4:21 Global spinlock vs local bit spin locks Nick Piggin
2005-06-17  4:45 ` Andrew Morton [this message]
2005-06-17  8:50   ` Andi Kleen
2005-06-17  4:45 ` David S. Miller
2005-06-17  4:46 ` William Lee Irwin III
2005-06-17  4:52   ` Andrew Morton
2005-06-17  8:35   ` Nick Piggin
2005-06-17  8:45     ` William Lee Irwin III
2005-06-17  9:21       ` Nick Piggin
2005-06-17  9:28         ` William Lee Irwin III
2005-06-17  8:54     ` Andi Kleen
2005-06-17  9:15       ` William Lee Irwin III
2005-06-17  9:27       ` Nick Piggin

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