From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: [PATCH 3/3] Implement linux-aio backend Date: Fri, 18 Apr 2008 14:46:25 -0300 Message-ID: <20080418174624.GA23124@dmt> References: <1208460412-27567-1-git-send-email-aliguori@us.ibm.com> <1208460412-27567-3-git-send-email-aliguori@us.ibm.com> <20080418150956.GB19341@dmt> <4808BBC9.6040502@us.ibm.com> Reply-To: qemu-devel@nongnu.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm-devel@lists.sourceforge.net, qemu-devel@nongnu.org To: Anthony Liguori Return-path: Content-Disposition: inline In-Reply-To: <4808BBC9.6040502@us.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org List-Id: kvm.vger.kernel.org On Fri, Apr 18, 2008 at 10:18:33AM -0500, Anthony Liguori wrote: > >Sleeping in the context of vcpu's is extremely bad (eg virtio-block > >blocks in write() throttling which kills performance). It should wait > >on IO completions instead (qemu-kvm.c creates a pthread "waitqueue" to > >resolve that issue). > > > >Other than that looks fine to me, will give it a try. > > > > FWIW, I'm not getting wonderful results in KVM. It's hard to tell > though because time seems wildly inaccurate (even with kvm clock in the > guest). The time issue appears unrelated to this set of patches. Oh, you won't get completion signals on the aio eventfd. You might want to try the select-with-timeout() stuff. Will submit that with proper signalfd emulation shortly.