Re: [Qemu-devel] [PATCH 0/2] Dynamic module support for block drivers

[Marc Marí]

On Thu, 3 Sep 2015 17:12:29 +0100
Stefan Hajnoczi <address@hidden> wrote:

> On Mon, Aug 17, 2015 at 10:09:33AM +0200, Marc Marí wrote:
> > The current module infrastructure has been improved to enable
> > dynamic module loading.
> > 
> > This reduces the load time for very simple guests. For the following
> > configuration (very loaded)
> > 
> > ./configure --enable-sdl --enable-gtk --enable-vte --enable-curses \
> >     --enable-vnc --enable-vnc-{jpeg,tls,sasl,png} --enable-virtfs \
> >     --enable-brlapi --enable-curl --enable-fdt --enable-bluez \
> >     --enable-kvm --enable-rdma --enable-uuid --enable-vde \
> >     --enable-linux-aio --enable-cap-ng --enable-attr
> > --enable-vhost-net \ --enable-vhost-scsi --enable-spice
> > --enable-rbd --enable-libiscsi \ --enable-smartcard-nss
> > --enable-guest-agent --enable-libusb \ --enable-usb-redir
> > --enable-lzo --enable-snappy --enable-bzip2 \ --enable-seccomp
> > --enable-coroutine-pool --enable-glusterfs \ --enable-tpm
> > --enable-libssh2 --enable-vhdx --enable-numa \ --enable-tcmalloc
> > --target-list=x86_64-softmmu
> > 
> > With modules disabled, there are 142 libraries loaded at startup.
> > Time is the following:
> >  LD time: 0.065 seconds
> >  QEMU time: 0.02 seconds
> >  Total time: 0.085 seconds
> > 
> > With this patch series and modules enabled, there are 128 libraries
> > loaded at startup. Time is the following:
> >  LD time: 0.02 seconds
> >  QEMU time: 0.02 seconds
> >  Total time: 0.04 seconds
> > 
> > Where LD time is the time between the program startup and the jump
> > to main, and QEMU time is the time between the start of main and
> > the first kvm_entry.
> > 
> > These results are just with a few block drivers, that were already
> > a module. Adding more modules (block or not block) should be easy,
> > and will reduce the load time even more.
> 
> Which QEMU command-line did you benchmark?
> 
> Did you have a UI enabled (SDL/GTK/VNC)?

x86_64-softmmu/qemu-system-x86_64 --enable-kvm \
    -kernel /boot/vmlinuz-4.1.4-200.fc22.x86_64 -nographic

Thanks
Marc