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| author | Daniel P. Berrange | 2017-09-27 14:53:35 +0200 |
|---|---|---|
| committer | Max Reitz | 2017-10-06 16:30:47 +0200 |
| commit | 161253e2d0a83a1b33bca019c6e926013e1a03db (patch) | |
| tree | 607d4598e3b8b2183726c2463aeed40352e24e60 /include/crypto | |
| parent | iotests: Add test 197 for covering copy-on-read (diff) | |
| download | qemu-161253e2d0a83a1b33bca019c6e926013e1a03db.tar.gz qemu-161253e2d0a83a1b33bca019c6e926013e1a03db.tar.xz qemu-161253e2d0a83a1b33bca019c6e926013e1a03db.zip | |
block: use 1 MB bounce buffers for crypto instead of 16KB
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.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170927125340.12360-2-berrange@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'include/crypto')
0 files changed, 0 insertions, 0 deletions