On Tue, Jun 27, 2017 at 02:34:10PM +0200, Peter Lieven wrote: > this adds support for optimized zlib settings which almost > tripples the compression speed while maintaining about > the same compressed size. > > Signed-off-by: Peter Lieven <p...@kamp.de> > --- > block/qcow2-cluster.c | 3 ++- > block/qcow2.c | 11 +++++++++-- > block/qcow2.h | 1 + > qemu-img.texi | 1 + > 4 files changed, 13 insertions(+), 3 deletions(-) > diff --git a/qemu-img.texi b/qemu-img.texi > index 043c1ba..83a5db2 100644 > --- a/qemu-img.texi > +++ b/qemu-img.texi > @@ -627,6 +627,7 @@ The following options are available if support for the > respective libraries > has been enabled at compile time: > > zlib Uses standard zlib compression (default) > + zlib-fast Uses zlib compression with optimized compression > parameters
This looks like a poor design from a future proofing POV. I would much rather see us introduce a more flexible modelling of compression at the QAPI layer which lets us have tunables for each algorith, in the same way that the qcow2 built-in encryption now has ability to set tunables for each algorithm. eg your "zlib-fast" impl which just uses zlib with a window size of -15 could be expressed as qemu-img create -o compress.format=zlib,compress.window=-15 > lzo Uses LZO1X compression Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
