[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [RFC PATCH 1/1] ceph/rbd block driver for qemu-kvm

From: Anthony Liguori
Subject: Re: [Qemu-devel] [RFC PATCH 1/1] ceph/rbd block driver for qemu-kvm
Date: Mon, 24 May 2010 14:19:34 -0500
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv: Gecko/20091209 Fedora/3.0-4.fc12 Lightning/1.0pre Thunderbird/3.0

On 05/24/2010 06:03 AM, Avi Kivity wrote:
On 05/24/2010 11:27 AM, Stefan Hajnoczi wrote:
On Sun, May 23, 2010 at 1:01 PM, Avi Kivity<address@hidden>  wrote:
On 05/21/2010 12:29 AM, Anthony Liguori wrote:
I'd be more interested in enabling people to build these types of storage
systems without touching qemu.

Both sheepdog and ceph ultimately transmit I/O over a socket to a central
daemon, right?
That incurs an extra copy.
Besides a shared memory approach, I wonder if the splice() family of
syscalls could be used to send/receive data through a storage daemon
without the daemon looking at or copying the data?

Excellent idea.

splice() eventually requires a copy. You cannot splice() to linux-aio so you'd have to splice() to a temporary buffer and then call into linux-aio. With shared memory, you can avoid ever bringing the data into memory via O_DIRECT and linux-aio.


Anthony Liguori

reply via email to

[Prev in Thread] Current Thread [Next in Thread]