On 2017-09-12 13:28, Daniel P. Berrange wrote: > Using 16KB bounce buffers creates a significant performance > penalty for I/O to encrypted volumes on storage which high > I/O latency (rotating rust & network drives), because it > triggers lots of fairly small I/O operations. > > On tests with rotating rust, and cache=none|directsync, > write speed increased from 2MiB/s to 32MiB/s, on a par > with that achieved by the in-kernel luks driver. With > other cache modes the in-kernel driver is still notably > faster because it is able to report completion of the > I/O request before any encryption is done, while the > in-QEMU driver must encrypt the data before completion. > > Reviewed-by: Eric Blake <ebl...@redhat.com> > Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com> > Signed-off-by: Daniel P. Berrange <berra...@redhat.com> > --- > block/crypto.c | 12 +++++------- > 1 file changed, 5 insertions(+), 7 deletions(-)
Reviewed-by: Max Reitz <mre...@redhat.com>
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