On 16/12/2014 21:26, Paolo Bonzini wrote: > >> I could reproduce this very well on a random OS image that I had around. >> This is raw over XFS over dm-crypt, and the image is about 75% sparse >> (8.2G used over 35G). I only get 1-2%, but still it's visible. >> >> However I can hardly reproduce it when using a partition directly: >> >> old new >> mean 9.9565 9.9636 (+0.07%) >> stddev 0.0405 0.0537 >> min 9.871 9.867 >> median 9.973 9.971 >> max 10.01 10.053 >> count 20 20 >> >> I haven't tried removing layers (e.g. fully-allocated XFS image without >> dm-crypt). > > Could not reproduce it with a fully-allocated XFS image, on the contrary > the patched QEMU is a bit faster: > > old new > mean 14.83325 14.82660 > stddev 0.016930 0.010328 > min 14.819 14.818 > max 14.854 14.883 > median 14.8225 14.8255 > count 20 20
Same for 50% sparse XFS image, patched QEMU a bit faster: old new Mean 8.31285 8.30625 stddev 0.03690 0.03333 min 8.277 8.276 max 8.378 8.382 median 8.292 8.2905 count 20 20