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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Olof Johansson <olof@lixom.net>
Cc: npiggin@suse.de, linuxppc-dev@ozlabs.org,
	Anton Blanchard <anton@samba.org>
Subject: Re: [PATCH 6/6] powerpc: Use lwsync for acquire barrier if CPU supports it
Date: Tue, 16 Feb 2010 15:19:03 +1100	[thread overview]
Message-ID: <1266293943.16346.169.camel@pasglop> (raw)
In-Reply-To: <20100216042238.GB12167@lixom.net>

On Mon, 2010-02-15 at 22:22 -0600, Olof Johansson wrote:
> 
> Turns out this one hurts PA6T performance quite a bit, lwsync seems to be
> significantly more expensive there. I see a 25% drop in the microbenchmark
> doing pthread_lock/unlock loops on two cpus.
> 
> Taking out the CPU_FTR_LWSYNC will solve it, it's a bit unfortunate since
> the sync->lwsync changes definitely still can, and should, be done. 

So we should use a different feature bit. No biggie. If needed we can
split them more anyways.

Cheers,
Ben.

  reply	other threads:[~2010-02-16  4:19 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-10 10:57 [PATCH 1/6] powerpc: Use lwarx hint in spinlocks Anton Blanchard
2010-02-10 11:02 ` [PATCH 2/6] powerpc: Use lwarx/ldarx hint in bit locks Anton Blanchard
2010-02-10 11:03   ` [PATCH 3/6] powerpc: Convert open coded native hashtable bit lock Anton Blanchard
2010-02-10 11:04     ` [PATCH 4/6] powerpc: Rename LWSYNC_ON_SMP to PPC_RELEASE_BARRIER, ISYNC_ON_SMP to PPC_ACQUIRE_BARRIER Anton Blanchard
2010-02-10 11:07       ` [PATCH 5/6] powerpc: Fix lwsync patching code on 64bit Anton Blanchard
2010-02-10 11:10         ` [PATCH 6/6] powerpc: Use lwsync for acquire barrier if CPU supports it Anton Blanchard
2010-02-11  7:09           ` Nick Piggin
2010-02-17  9:43             ` Anton Blanchard
2010-02-17 10:41               ` Nick Piggin
2010-02-17 12:12                 ` Benjamin Herrenschmidt
2010-02-16  4:22           ` Olof Johansson
2010-02-16  4:19             ` Benjamin Herrenschmidt [this message]
2010-02-16  6:07               ` Olof Johansson
2010-03-19  1:08       ` [PATCH 4/6] powerpc: Rename LWSYNC_ON_SMP to PPC_RELEASE_BARRIER, ISYNC_ON_SMP to PPC_ACQUIRE_BARRIER Nick Piggin
2010-03-19  1:36         ` Benjamin Herrenschmidt
2010-02-11  6:56 ` [PATCH 1/6] powerpc: Use lwarx hint in spinlocks Nick Piggin
2010-02-17  9:37   ` Anton Blanchard
2010-02-17 10:22     ` Nick Piggin
2010-02-16  4:16 ` Olof Johansson

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