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

[Marc Marí]

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.

Marc Marí (2):
  Add dynamic module loading for block drivers
  Add dynamic generation of module_block.h

 .gitignore                      |   1 +
 Makefile                        |  10 ++-
 block.c                         |  73 +++++++++++++++++++++-
 configure                       |   2 +-
 include/qemu/module.h           |   3 +
 include/qemu/module_block.h     |  89 +++++++++++++++++++++++++++
 scripts/modules/module_block.py | 132 ++++++++++++++++++++++++++++++++++++++++
 util/module.c                   |  38 ++++--------
 8 files changed, 314 insertions(+), 34 deletions(-)
 create mode 100644 include/qemu/module_block.h
 create mode 100755 scripts/modules/module_block.py

-- 
2.4.3