Date: Tue, 09 May 2006 23:39:58 -0700 (PDT)
Message-Id: <20060509.233958.73723993.davem@davemloft.net>
To: paulus@samba.org
Cc: olof@lixom.net, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
       linuxppc-dev@ozlabs.org
Subject: Re: [RFC/PATCH] Make powerpc64 use __thread for per-cpu variables
From: "David S. Miller" <davem@davemloft.net>
In-Reply-To: <17505.34919.750295.170941@cargo.ozlabs.ibm.com>
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	<20060510051649.GD1794@lixom.net>
	<17505.34919.750295.170941@cargo.ozlabs.ibm.com>
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From: Paul Mackerras <paulus@samba.org>
Date: Wed, 10 May 2006 16:29:59 +1000

> I have moved current, smp_processor_id and a couple of other things to
> per-cpu variables, and that results in the kernel text being about 8k
> smaller than without any of these __thread patches.  Performance seems
> to be very slightly better but it's hard to be sure that the change is
> statistically significant, from the measurements I've done so far.

That first cache line of current_thread_info() should be so hot that
it's probably just fine to use current_thread_info()->task since
you're just doing a mask on a fixed register (r1) to implement that.
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