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| author | Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> | 2021-12-17 17:46:54 +0100 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2022-01-14 12:03:16 +0100 |
| commit | 96054c76ff2db74165385a69f234c57a6bbc941e (patch) | |
| tree | 7426f47bd77a9a4153f2c88fd043947daf5580e8 /tests | |
| parent | 51cd8bddd63540514d44808f7920811439baa253 (diff) | |
| download | qemu-96054c76ff2db74165385a69f234c57a6bbc941e.zip qemu-96054c76ff2db74165385a69f234c57a6bbc941e.tar.gz qemu-96054c76ff2db74165385a69f234c57a6bbc941e.tar.bz2 | |
qemu-img: make is_allocated_sectors() more efficient
Consider the case when the whole buffer is zero and end is unaligned.
If i <= tail, we return 1 and do one unaligned WRITE, RMW happens.
If i > tail, we do on aligned WRITE_ZERO (or skip if target is zeroed)
and again one unaligned WRITE, RMW happens.
Let's do better: don't fragment the whole-zero buffer and report it as
ZERO: in case of zeroed target we just do nothing and avoid RMW. If
target is not zeroes, one unaligned WRITE_ZERO should not be much worse
than one unaligned WRITE.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20211217164654.1184218-3-vsementsov@virtuozzo.com>
Tested-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'tests')
| -rw-r--r-- | tests/qemu-iotests/122.out | 8 |
1 files changed, 2 insertions, 6 deletions
diff --git a/tests/qemu-iotests/122.out b/tests/qemu-iotests/122.out index 69b8e8b..e18766e 100644 --- a/tests/qemu-iotests/122.out +++ b/tests/qemu-iotests/122.out @@ -201,9 +201,7 @@ convert -S 4k { "start": 8192, "length": 4096, "depth": 0, "present": true, "zero": false, "data": true, "offset": OFFSET}, { "start": 12288, "length": 4096, "depth": 0, "present": false, "zero": true, "data": false}, { "start": 16384, "length": 4096, "depth": 0, "present": true, "zero": false, "data": true, "offset": OFFSET}, -{ "start": 20480, "length": 46080, "depth": 0, "present": false, "zero": true, "data": false}, -{ "start": 66560, "length": 1024, "depth": 0, "present": true, "zero": false, "data": true, "offset": OFFSET}, -{ "start": 67584, "length": 67041280, "depth": 0, "present": false, "zero": true, "data": false}] +{ "start": 20480, "length": 67088384, "depth": 0, "present": false, "zero": true, "data": false}] convert -c -S 4k [{ "start": 0, "length": 1024, "depth": 0, "present": true, "zero": false, "data": true}, @@ -215,9 +213,7 @@ convert -c -S 4k convert -S 8k [{ "start": 0, "length": 24576, "depth": 0, "present": true, "zero": false, "data": true, "offset": OFFSET}, -{ "start": 24576, "length": 41984, "depth": 0, "present": false, "zero": true, "data": false}, -{ "start": 66560, "length": 1024, "depth": 0, "present": true, "zero": false, "data": true, "offset": OFFSET}, -{ "start": 67584, "length": 67041280, "depth": 0, "present": false, "zero": true, "data": false}] +{ "start": 24576, "length": 67084288, "depth": 0, "present": false, "zero": true, "data": false}] convert -c -S 8k [{ "start": 0, "length": 1024, "depth": 0, "present": true, "zero": false, "data": true}, |