From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1JryG2-0005Ga-9i for qemu-devel@nongnu.org; Fri, 02 May 2008 12:37:14 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1JryFy-0005F3-DM for qemu-devel@nongnu.org; Fri, 02 May 2008 12:37:13 -0400 Received: from [199.232.76.173] (port=35825 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1JryFy-0005Ey-8x for qemu-devel@nongnu.org; Fri, 02 May 2008 12:37:10 -0400 Received: from wr-out-0506.google.com ([64.233.184.236]) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1JryFx-0000x6-SD for qemu-devel@nongnu.org; Fri, 02 May 2008 12:37:10 -0400 Received: by wr-out-0506.google.com with SMTP id c49so998805wra.19 for ; Fri, 02 May 2008 09:37:06 -0700 (PDT) Message-ID: <69304d110805020937l2f867cadrd7c906b8eb77b3f6@mail.gmail.com> Date: Fri, 2 May 2008 17:37:05 +0100 From: "Antonio Vargas" Subject: Re: [kvm-devel] [Qemu-devel] Re: [PATCH 1/3] Refactor AIO interface to allow other AIO implementations In-Reply-To: <20080422153616.GC10229@shareable.org> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_6237_11111782.1209746225842" References: <4808BCF3.3060200@us.ibm.com> <20080420154943.GB14268@shareable.org> <480B8EDC.6060507@qumranet.com> <20080420233913.GA23292@shareable.org> <480C36A3.6010900@qumranet.com> <20080421121028.GD4193@shareable.org> <480D9D74.5070801@qumranet.com> <20080422142847.GC4849@shareable.org> <480DFE43.8060509@qumranet.com> <20080422153616.GC10229@shareable.org> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org ------=_Part_6237_11111782.1209746225842 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline On Tue, Apr 22, 2008 at 4:36 PM, Jamie Lokier wrote: *snip* > > Btw, regarding QEMU: QEMU gets requests _after_ sorting by the guest's > elevator, then submits them to the host's elevator. If the guest and > host elevators are both configured 'anticipatory', do the anticipatory > delays add up? > Anticipatory is non-work-conserving. If the data is going to end passing thru host's deadline scheduler, probably it is better to the guest with deadline or maybe even no-op since it doesn't really know anything about the real disk locations of the data. -- Greetz, Antonio Vargas aka winden of rgba^ntw^bg http://winden.wordpress.com/ windenntw@gmail.com Every day, every year you have to work you have to study you have to scene. ------=_Part_6237_11111782.1209746225842 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline

On Tue, Apr 22, 2008 at 4:36 PM, Jamie Lokier <jamie@shareable.org> wrote:

*snip*
 

Btw, regarding QEMU: QEMU gets requests _after_ sorting by the guest's
elevator, then submits them to the host's elevator.  If the guest and
host elevators are both configured 'anticipatory', do the anticipatory
delays add up?


Anticipatory is non-work-conserving. If the data is going to end passing thru
host's deadline scheduler, probably it is better to the guest with deadline
or maybe even no-op since it doesn't really know anything about the real
disk locations of the data.

--
Greetz, Antonio Vargas aka winden of rgba^ntw^bg

http://winden.wordpress.com/
windenntw@gmail.com

Every day, every year
you have to work
you have to study
you have to scene. ------=_Part_6237_11111782.1209746225842--