On Tue, Oct 11, 2011 at 11:50:01AM +0200, Avi Kivity wrote: > On 10/11/2011 11:49 AM, Daniel P. Berrange wrote: > >On Tue, Oct 11, 2011 at 11:39:36AM +0200, Avi Kivity wrote: > >> On 10/11/2011 11:27 AM, Daniel P. Berrange wrote: > >> >> >For comparison I also did a test building a bootable ISO using > >> ISOLinux. > >> >> >This required 700 ms for the boot time, which is appoximately 1/2 > >> the > >> >> >time reqiured for direct kernel/initrd boot. But you have to then > >> add > >> >> >on time required to build the ISO on every boot, to add custom > >> kernel > >> >> >command line args. So while ISO is faster than LinuxBoot currently > >> >> >there is still non-negligable overhead here that I want to avoid. > >> >> > >> >> You can accept parameters from virtio-serial or some other channel. > >> >> Is there any reason you need them specifically as *kernel* command > >> >> line parameters? > >> > > >> >Well some of the parameters are actually kernel parameters :-) The rest > >> >are things I pass to the 'init' process which runs in the initrd. When > >> >this process first starts the only things it can easily access are those > >> >builtin to the kernel image, so data available from /proc or /sys like > >> >the /proc/cmdline file. It hasn't even loaded things like the > >> virtio-serial > >> >or virtio-9pfs kernel modules at this point. > >> > > >> > >> It could, if it wanted to. It's completely custom, yes? > > > >I'm thinking primarily about debug related parameters, which need to be > >used as soon the process starts, not delayed until after we've loaded > >kernel modules at which point the step we wanted to debug is already > >past. > > Ah, so there's no issue in regenerating the image if you want to debug.
Compared to just altering the -append arg to QEMU, rebuilding the initrd image and init program is a PITA. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
