From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58656) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bC5uG-0007m6-LJ for qemu-devel@nongnu.org; Sun, 12 Jun 2016 09:58:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bC5uF-0002lo-SE for qemu-devel@nongnu.org; Sun, 12 Jun 2016 09:58:28 -0400 Date: Sun, 12 Jun 2016 15:58:16 +0200 From: Andrew Jones Message-ID: <20160612135816.unnyoyk5wmizympf@hawk.localdomain> References: <1465580427-13596-1-git-send-email-drjones@redhat.com> <575BB2C6.2050603@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <575BB2C6.2050603@redhat.com> Subject: Re: [Qemu-devel] [PATCH RFC 00/16] Rework SMP parameters List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth Cc: qemu-devel@nongnu.org, qemu-ppc@nongnu.org, qemu-arm@nongnu.org, peter.maydell@linaro.org, ehabkost@redhat.com, agraf@suse.de, pbonzini@redhat.com, imammedo@redhat.com, dgibson@redhat.com, david@gibson.dropbear.id.au On Sat, Jun 11, 2016 at 08:42:14AM +0200, Thomas Huth wrote: > On 10.06.2016 19:40, Andrew Jones wrote: > > This series is a first step in eliminating smp_* global > > variables (the last patch gets rid of two of them!) And, it's > > a first step in deprecating '-smp' in favor of using machine > > properties, e.g. > > qemu -machine pc,sockets=2,cores=2,threads=2,maxcpus=8,cpus=8 ... > > Why isn't '-smp' good enough anymore so that it got to be deprecated? > cpu topology is machine state, and the QEMU style of providing state values for objects is through properties. So adding properties brings cpu topology descriptions more in line. Keeping a redundant (not "in line") command line option could confuse things. Also, switching how the command line is used provides a clean breaking point. -smp assumes values when none are provided. This can lead to unexpected results for some machines. Rather than trying to code every assumption possible, it's easier to just require all properties be specified. Machines are still free to provide short-hand properties to get defaults, if the 45 character collection of properties is too annoying to use all the time (I agree that it may be). Thanks, drew