From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Nick Piggin <npiggin@suse.de>
Cc: linuxppc-dev@ozlabs.org, paulus@samba.org
Subject: Re: [patch 2/2] powerpc: optimise smp_wmb
Date: Wed, 21 May 2008 11:43:00 -0400 [thread overview]
Message-ID: <1211384580.8297.199.camel@pasglop> (raw)
In-Reply-To: <20080521153420.GG8897@wotan.suse.de>
On Wed, 2008-05-21 at 17:34 +0200, Nick Piggin wrote:
> On Wed, May 21, 2008 at 11:26:32AM -0400, Benjamin Herrenschmidt wrote:
> >
> > On Wed, 2008-05-21 at 16:12 +0200, Nick Piggin wrote:
> > > lwsync is the recommended method of store/store ordering on caching enabled
> > > memory. For those subarchs which have lwsync, use it rather than eieio for
> > > smp_wmb.
> >
> > Yuck... existence of lwsync depends on the processor at boot time...
>
> Not according to the __stringify(LWSYNC) that I just removed. At least,
> presumably it is always present on 64 bit processors, and 32 bit ones
> will be no worse off as they'll continue just using eieio.
No, it doesn't exist on power3, but it degrades into a sync
Ben.
next prev parent reply other threads:[~2008-05-21 15:43 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-21 14:10 [patch 1/2] powerpc: rmb fix Nick Piggin
2008-05-21 14:12 ` [patch 2/2] powerpc: optimise smp_wmb Nick Piggin
2008-05-21 15:26 ` Benjamin Herrenschmidt
2008-05-21 15:34 ` Nick Piggin
2008-05-21 15:43 ` Benjamin Herrenschmidt [this message]
2008-05-21 15:47 ` Nick Piggin
2008-05-21 16:02 ` Benjamin Herrenschmidt
2008-05-21 20:51 ` Segher Boessenkool
2008-05-21 16:01 ` Nick Piggin
2008-05-21 20:12 ` Segher Boessenkool
2008-05-21 20:44 ` Benjamin Herrenschmidt
2008-05-21 22:07 ` Segher Boessenkool
2008-05-22 0:30 ` Nick Piggin
2008-05-21 20:16 ` Segher Boessenkool
2008-05-21 15:27 ` [patch 1/2] powerpc: rmb fix Benjamin Herrenschmidt
2008-05-21 15:32 ` Nick Piggin
2008-05-21 15:43 ` Benjamin Herrenschmidt
2008-05-23 2:14 ` Paul Mackerras
2008-05-23 4:40 ` Nick Piggin
2008-05-23 4:53 ` Paul Mackerras
2008-05-23 5:48 ` Nick Piggin
2008-05-23 6:40 ` Paul Mackerras
2008-05-26 1:38 ` Nick Piggin
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