The test cases considered so far:
314 (new test suite):
1. Check that compression mode isn't compatible with "-f raw" (raw
format doesn't support compression).
2. Check that rebasing an image onto no backing file preserves the data
and writes the copied clusters actually compressed.
3. Same as 2, but with a raw backing file (i.e. the clusters copied from the
backing are originally uncompressed -- we check they end up compressed
after being merged).
4. Remove a single delta from a backing chain, perform the same checks
as in 2.
5. Check that even when backing and overlay are initially uncompressed,
copied clusters end up compressed when rebase with compression is
performed.
271:
1. Check that when target image has subclusters, rebase with compression
will make an entire cluster containing the written subcluster
compressed.
Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-ID: <20230919165804.439110-9-andrey.drobyshev@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
As the previous commit changes the logic of "qemu-img rebase" (it's using
write alignment now), let's add a couple more test cases which would
ensure it works correctly. In particular, the following scenarios:
024: add test case for rebase within one backing chain when the overlay
cluster size > backings cluster size;
271: add test case for rebase images that contain subclusters. Check
that no extra allocations are being made.
Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-ID: <20230919165804.439110-7-andrey.drobyshev@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
There is no conflict and no dependency if we have parallel writes to
different subclusters of one cluster when the cluster itself is already
allocated. So, relax extra dependency.
Measure performance:
First, prepare build/qemu-img-old and build/qemu-img-new images.
cd scripts/simplebench
./img_bench_templater.py
Paste the following to stdin of running script:
qemu_img=../../build/qemu-img-{old|new}
$qemu_img create -f qcow2 -o extended_l2=on /ssd/x.qcow2 1G
$qemu_img bench -c 100000 -d 8 [-s 2K|-s 2K -o 512|-s $((1024*2+512))] \
-w -t none -n /ssd/x.qcow2
The result:
All results are in seconds
------------------ --------- ---------
old new
-s 2K 6.7 ± 15% 6.2 ± 12%
-7%
-s 2K -o 512 13 ± 3% 11 ± 5%
-16%
-s $((1024*2+512)) 9.5 ± 4% 8.4
-12%
------------------ --------- ---------
So small writes are more independent now and that helps to keep deeper
io queue which improves performance.
271 iotest output becomes racy for three allocation in one cluster.
Second and third writes may finish in different order. Second and
third requests don't depend on each other any more. Still they both
depend on first request anyway. Filter out second and third write
offsets to cover both possible outputs.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210824101517.59802-4-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
[hreitz: s/ an / and /]
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
We are going to be stricter about comparing test result with .out
files. So, fix some whitespaces now.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210116134424.82867-4-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <e6dd0429cafe84ca603179c298a8703bddca2904.1594396418.git.berto@igalia.com>
[mreitz: Use env in shebang line]
Signed-off-by: Max Reitz <mreitz@redhat.com>
Andrey Drobyshev