From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [Qemu-devel] Re: [PATCH 2/3] Move aio implementation out of raw block driver Date: Tue, 23 Sep 2008 13:28:50 -0500 Message-ID: <48D93562.6020009@codemonkey.ws> References: <1222125454-21744-1-git-send-email-ryanh@us.ibm.com> <1222125454-21744-3-git-send-email-ryanh@us.ibm.com> <48D85849.2080302@us.ibm.com> <20080923143909.GK31395@us.ibm.com> <48D902EB.8070701@redhat.com> <48D91403.8090007@us.ibm.com> <48D92FC2.2000203@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Ryan Harper , Marcelo Tosatti , qemu-devel@nongnu.org, kvm@vger.kernel.org To: Gerd Hoffmann Return-path: Received: from nf-out-0910.google.com ([64.233.182.189]:6178 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753443AbYIWS35 (ORCPT ); Tue, 23 Sep 2008 14:29:57 -0400 Received: by nf-out-0910.google.com with SMTP id d3so764820nfc.21 for ; Tue, 23 Sep 2008 11:29:50 -0700 (PDT) In-Reply-To: <48D92FC2.2000203@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Gerd Hoffmann wrote: > Anthony Liguori wrote: > >> Gerd Hoffmann wrote: >> >>> How about providing a aio interface implementation which simply uses >>> read/write syscalls (thereby not being really async obviously)? Then >>> use that as fallback instead of aio emulation? And also drop CONFIG_AIO >>> then? >>> >> Yeah, this is basically what block-raw-posix does today. I was thinking >> the same thing. I was also thinking that you could do an aio >> implementation for win32 and possibly reunify block-raw-posix and >> block-raw-linux. >> > > Sure, that the next logical steps. Later we can also convert all > block-* drivers to the new aio interface and subsequently drop alot of > dead block layer code. > Yup. >> But before going down this route, I want to see if linux-aio is really >> the right tool for the job. >> > > IMHO this all makes sense even in case linux-aio turns out to not be > worth it. > Yes, I agree. For a bit of a spoiler, initial results are that cache=off + my fd_pool patch is getting equivalent performance to linux-aio so it's looking like we can avoid linux-aio for now. Regards, Anthony Liguori > cheers, > Gerd > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >