From: Matt Sealey <matt@genesi-usa•com>
To: Gabriel Paubert <paubert@iram•es>
Cc: ppc-dev <linuxppc-dev@ozlabs•org>
Subject: Re: "atomic" 64-bit math on 32-bit ppc's?
Date: Tue, 04 Sep 2007 13:31:07 +0100 [thread overview]
Message-ID: <46DD500B.4020207@genesi-usa.com> (raw)
In-Reply-To: <20070904113937.GA3994@iram.es>
Gabriel Paubert wrote:
> On Tue, Sep 04, 2007 at 12:09:22PM +0100, Matt Sealey wrote:
>> Hi guys,
>>
>> The Solaris PPC code drop included most of these functions for 32-bit ops on
>> 32-bit PPC architectures but the 64-bit operations are not present. What I
>> a not clear on is the operation of lwarx and stwcx. and if they will work if
>> you are doing operations on two words at a time.
>
> No. There is a single reservation for a single word.
This is what I gathered from the programming environments manual at least.
> the 64 bit operations inside a spinlock on PPC32, and then select the
> number /location of spinlock(s) based on your needs, from one global
> per machine to one per 64 bit variable if you find excessive contention.
Okay that makes sense, but it would have to be a super global big lock,
I don't think the code is there in ZFS to give every 64-bit variable it's
own dedicated spinlock (kind of an overhaul) and I'm trying to be fast..
--
Matt Sealey <matt@genesi-usa•com>
Genesi, Manager, Developer Relations
next prev parent reply other threads:[~2007-09-04 12:29 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-04 11:09 "atomic" 64-bit math on 32-bit ppc's? Matt Sealey
2007-09-04 11:39 ` Gabriel Paubert
2007-09-04 12:31 ` Matt Sealey [this message]
2007-09-04 16:02 ` Gabriel Paubert
2007-09-04 17:40 ` Matt Sealey
2007-09-05 1:04 ` David Gibson
2007-09-04 18:48 ` Scott Wood
2007-09-06 13:21 ` Segher Boessenkool
2007-09-06 13:43 ` Scott Wood
2007-09-06 14:09 ` Segher Boessenkool
2007-09-10 20:39 ` Jon Loeliger
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