From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: KVM call agenda for Apr 27 Date: Tue, 27 Apr 2010 08:19:06 -0500 Message-ID: <4BD6E44A.8050204@codemonkey.ws> References: <20100426172634.GC15278@x200.localdomain> <4BD5D28C.7080700@codemonkey.ws> <20100426221258.GH15278@x200.localdomain> <4BD61584.9080208@codemonkey.ws> <20100427111140.GF10044@redhat.com> <4BD6DFD2.7050509@codemonkey.ws> <20100427130556.GH10044@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Chris Wright , kvm@vger.kernel.org, qemu-devel@nongnu.org To: Gleb Natapov Return-path: Received: from mail-qy0-f179.google.com ([209.85.221.179]:49188 "EHLO mail-qy0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755617Ab0D0NTL (ORCPT ); Tue, 27 Apr 2010 09:19:11 -0400 Received: by qyk9 with SMTP id 9so19309194qyk.1 for ; Tue, 27 Apr 2010 06:19:10 -0700 (PDT) In-Reply-To: <20100427130556.GH10044@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 04/27/2010 08:05 AM, Gleb Natapov wrote: > On Tue, Apr 27, 2010 at 08:00:02AM -0500, Anthony Liguori wrote: > >> On 04/27/2010 06:11 AM, Gleb Natapov wrote: >> >>> Network cards have low number of rx/tx buffers interrupt. This is also >>> heuristic. Do you think driver should poll for this event instead and >>> NIC designers just wasted their time designing the feature? >>> >> I don't see how the two cases are at all similar. >> >> > They are the same. They send notification when resource is low. > > >> More importantly, I don't see what the burden is of polling when >> you're talking about a very unusual statistic that has a very >> limited use case. >> >> > Poll is the wrong answer. Always. The statistic is very common and has > wide use case unless you have unlimited storage. > Every management tool does polling in some form. They'll poll CPU stats, I/O stats, etc. The typical use-case for overcommitting storage is using file backed images. Using a dynamically growing LVM volume is almost certainly unique to RHEV-M. Regards, Anthony Liguori > -- > Gleb. >