From: Alexander Graf <agraf@suse.de>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Anthony Liguori <aliguori@us.ibm.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
mtosatti@redhat.com, OHMURA Kei <ohmura.kei@lab.ntt.co.jp>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Avi Kivity <avi@redhat.com>
Subject: Re: [Qemu-devel] Re: [PATCH v2] qemu-kvm: Speed up of the dirty-bitmap-traveling
Date: Wed, 10 Feb 2010 17:43:16 +0100 [thread overview]
Message-ID: <4B72E224.1090901@suse.de> (raw)
In-Reply-To: <4B72E051.8090008@codemonkey.ws>
Anthony Liguori wrote:
> On 02/10/2010 10:00 AM, Alexander Graf wrote:
>
>> On PPC the bitmap is Little Endian.
>>
>>
>
> Out of curiousity, why? It seems like an odd interface.
>
Because on PPC, you usually run PPC32 userspace code on a PPC64 kernel.
Unlike with x86, there's no real benefit in using 64 bit userspace.
So thanks to the nature of big endianness, that breaks our set_bit
helpers, because they assume you're using "long" data types for the
bits. While that's no real issue on little endian, since the next int is
just the high part of a u64, it messes everything up on ppc.
For more details, please just look in the archives on my patches to make
it little endian.
Alex
next prev parent reply other threads:[~2010-02-10 16:43 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-10 10:52 [Qemu-devel] [PATCH v2] qemu-kvm: Speed up of the dirty-bitmap-traveling OHMURA Kei
2010-02-10 13:10 ` [Qemu-devel] " Ulrich Drepper
2010-02-10 13:20 ` Avi Kivity
2010-02-10 15:54 ` Anthony Liguori
2010-02-10 15:57 ` Avi Kivity
2010-02-10 16:00 ` Alexander Graf
2010-02-10 16:35 ` Anthony Liguori
2010-02-10 16:43 ` Alexander Graf [this message]
2010-02-10 16:46 ` Avi Kivity
2010-02-10 16:47 ` Alexander Graf
2010-02-10 16:52 ` Avi Kivity
2010-02-10 16:54 ` Alexander Graf
2010-02-10 16:43 ` Avi Kivity
2010-02-10 15:55 ` Anthony Liguori
2010-02-12 2:03 ` OHMURA Kei
2010-02-14 12:34 ` Avi Kivity
2010-02-15 6:12 ` OHMURA Kei
2010-02-15 8:24 ` Alexander Graf
2010-02-16 11:16 ` OHMURA Kei
2010-02-16 11:18 ` Alexander Graf
2010-02-17 9:42 ` OHMURA Kei
2010-02-17 9:46 ` Alexander Graf
2010-02-18 5:57 ` OHMURA Kei
2010-02-18 10:30 ` Alexander Graf
2010-02-17 9:47 ` Avi Kivity
2010-02-17 9:49 ` Alexander Graf
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