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From: Anton Blanchard <anton@samba.org>
To: Manfred Spraul <manfred@colorfullife.com>
Cc: "Randy.Dunlap" <rddunlap@osdl.org>,
	Andrew Morton <akpm@digeo.com>,
	linux-kernel@vger.kernel.org, mbligh@aracnet.com
Subject: Re: [PATCH] patch-slab-split-03-tail
Date: Sat, 5 Oct 2002 10:14:34 +1000	[thread overview]
Message-ID: <20021005001434.GA15031@krispykreme> (raw)
In-Reply-To: <3D9E0760.8040507@colorfullife.com>


> <<<<<<<
> An object cache's CPU layer contains per-CPU state that must be 
> protected either by per-CPU locking or by disabling interrupts. We 
> selected per-CPU locking for several reasons:
> [...]
>  x    Performance. On most modern processors, grabbing an uncontended 
> lock is cheaper than modifying the processor interrupt level.
> <<<<<<<<
> 
> Which cpus have slow local_irq_disable() implementations? At least for 
> my Duron, this doesn't seem to be the case [~ 4 cpu cycles for cli]

Rusty did some tests and found on the intel chips he tested
local_irq_disable was slower. He posted the results to lkml a few weeks
ago.

On ppc64 it varies between chips.

Anton

      parent reply	other threads:[~2002-10-05  1:22 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-10-04 17:04 [PATCH] patch-slab-split-03-tail Manfred Spraul
2002-10-04 19:06 ` Andrew Morton
2002-10-04 19:07   ` Martin J. Bligh
2002-10-04 19:15     ` Andrew Morton
2002-10-04 19:15   ` Manfred Spraul
2002-10-04 20:22     ` Randy.Dunlap
2002-10-04 21:25       ` Manfred Spraul
2002-10-04 21:43         ` Robert Love
2002-10-04 22:30           ` Manfred Spraul
2002-10-05  0:14         ` Anton Blanchard [this message]

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