From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49059) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1am4Mn-00029t-Sy for qemu-devel@nongnu.org; Fri, 01 Apr 2016 15:04:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1am4Mj-0004tW-SW for qemu-devel@nongnu.org; Fri, 01 Apr 2016 15:04:21 -0400 Received: from mail-qg0-x22f.google.com ([2607:f8b0:400d:c04::22f]:35805) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1am4Mj-0004tS-NZ for qemu-devel@nongnu.org; Fri, 01 Apr 2016 15:04:17 -0400 Received: by mail-qg0-x22f.google.com with SMTP id y89so104236742qge.2 for ; Fri, 01 Apr 2016 12:04:17 -0700 (PDT) Date: Fri, 1 Apr 2016 15:04:15 -0400 From: Kevin O'Connor Message-ID: <20160401190415.GA13599@morn.lan> References: <20160401084456.GF32728@redhat.com> <1459502310.7011.37.camel@redhat.com> <20160401101733.GI32728@redhat.com> <1459508875.7011.62.camel@redhat.com> <20160401111139.GK32728@redhat.com> <1459510371.7011.63.camel@redhat.com> <20160401114947.GM32728@redhat.com> <20160401153540.GD25490@morn.lan> <20160401184131.GP32728@redhat.com> <20160401185902.GE19398@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20160401185902.GE19398@redhat.com> Subject: Re: [Qemu-devel] Why is SeaBIOS used with -kernel? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Richard W.M. Jones" Cc: marc.mari.barcelo@gmail.com, Paolo Bonzini , Stefan Hajnoczi , qemu-devel@nongnu.org, Gerd Hoffmann On Fri, Apr 01, 2016 at 07:59:02PM +0100, Richard W.M. Jones wrote: > On Fri, Apr 01, 2016 at 07:41:31PM +0100, Richard W.M. Jones wrote: > > Below are some benchmarks of the other things you mentioned. These > > are complete appliance boot-to-shutdown times [*not* just SeaBIOS]. > > All debugging has been disabled, and I'm using a slightly different > > kernel version, so these runs are not comparable to earlier results I > > posted. All times are the mean of 10 runs. The ± number is 1 > > standard deviation from the mean. > > > > In my estimation only CONFIG_FW_ROMFILE_LOAD=n seems to make a > > measurable difference. > > > > ---------------------------------------------------------------------- > > Ordinary qemu SeaBIOS configuration > > Result: 1227.5ms ±7.7ms > > > > -bios boot-fast.bin, as per my previous patch > > Result: 1113.7ms ±6.4ms > > > > Leaving CONFIG_XEN and CONFIG_THREADS at default settings > > Result: 1111.2ms ±3.8ms > > > > CONFIG_USE_SMM=n > > Result: 1116.0ms ±5.0ms > > > > CONFIG_FW_ROMFILE_LOAD=n > > Result: 1106.6ms ±5.0ms > > > > CONFIG_RELOCATE_INIT=n > > Result: 1104.7ms ±11.2ms > > ---------------------------------------------------------------------- > > Actually, CONFIG_RELOCATE_INIT=n looks like it is doing something, but > the error bars are quite large. > > Here's another one that makes a difference: > > CONFIG_BOOTORDER=n > Result: 1099.5ms ±3.7ms Are you sure you had CONFIG_DEBUG_LEVEL=0? Otherwise, it doesn't make sense that disabling CONFIG_BOOTORDER=n would change the boot time. Disabling CONFIG_DEBUG_SERIAL is not enough, because SeaBIOS also writes to port 0x402 as an internal debugging mechanism. -Kevin