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

[Stefan Hajnoczi]

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)?