qemu/tests/qemu-iotests/137.out

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QA output created by 137
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
=== Try setting valid values for all options ===
wrote 33554432/33554432 bytes at offset 0
32 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
read 33554432/33554432 bytes at offset 0
32 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
discard 33554432/33554432 bytes at offset 0
32 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
wrote 33554432/33554432 bytes at offset 0
32 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
read 33554432/33554432 bytes at offset 0
32 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
=== Try setting some invalid values ===
Parameter 'lazy-refcounts' expects 'on' or 'off'
cache-size, l2-cache-size and refcount-cache-size may not be set the same time
l2-cache-size may not exceed cache-size
refcount-cache-size may not exceed cache-size
L2 cache size too big
L2 cache entry size must be a power of two between 512 and the cluster size (65536)
L2 cache entry size must be a power of two between 512 and the cluster size (65536)
qcow2: Give the refcount cache the minimum possible size by default The L2 and refcount caches have default sizes that can be overridden using the l2-cache-size and refcount-cache-size (an additional parameter named cache-size sets the combined size of both caches). Unless forced by one of the aforementioned parameters, QEMU will set the unspecified sizes so that the L2 cache is 4 times larger than the refcount cache. This is based on the premise that the refcount metadata needs to be only a fourth of the L2 metadata to cover the same amount of disk space. This is incorrect for two reasons: a) The amount of disk covered by an L2 table depends solely on the cluster size, but in the case of a refcount block it depends on the cluster size *and* the width of each refcount entry. The 4/1 ratio is only valid with 16-bit entries (the default). b) When we talk about disk space and L2 tables we are talking about guest space (L2 tables map guest clusters to host clusters), whereas refcount blocks are used for host clusters (including L1/L2 tables and the refcount blocks themselves). On a fully populated (and uncompressed) qcow2 file, image size > virtual size so there are more refcount entries than L2 entries. Problem (a) could be fixed by adjusting the algorithm to take into account the refcount entry width. Problem (b) could be fixed by increasing a bit the refcount cache size to account for the clusters used for qcow2 metadata. However this patch takes a completely different approach and instead of keeping a ratio between both cache sizes it assigns as much as possible to the L2 cache and the remainder to the refcount cache. The reason is that L2 tables are used for every single I/O request from the guest and the effect of increasing the cache is significant and clearly measurable. Refcount blocks are however only used for cluster allocation and internal snapshots and in practice are accessed sequentially in most cases, so the effect of increasing the cache is negligible (even when doing random writes from the guest). So, make the refcount cache as small as possible unless the user explicitly asks for a larger one. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 9695182c2eb11b77cb319689a1ebaa4e7c9d6591.1523968389.git.berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-04-17 15:37:04 +03:00
Refcount cache size too big
Conflicting values for qcow2 options 'overlap-check' ('constant') and 'overlap-check.template' ('all')
Unsupported value 'blubb' for qcow2 option 'overlap-check'. Allowed are any of the following: none, constant, cached, all
Unsupported value 'blubb' for qcow2 option 'overlap-check'. Allowed are any of the following: none, constant, cached, all
Cache clean interval too big
=== Test transaction semantics ===
Unsupported value 'blubb' for qcow2 option 'overlap-check'. Allowed are any of the following: none, constant, cached, all
wrote 512/512 bytes at offset 0
512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
./common.rc: Killed ( if [ "${VALGRIND_QEMU}" == "y" ]; then
exec valgrind --log-file="${VALGRIND_LOGFILE}" --error-exitcode=99 "$QEMU_IO_PROG" $QEMU_IO_ARGS "$@";
else
exec "$QEMU_IO_PROG" $QEMU_IO_ARGS "$@";
fi )
incompatible_features 0x0
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
wrote 65536/65536 bytes at offset 0
64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
Parameter 'lazy-refcounts' expects 'on' or 'off'
qcow2: Marking image as corrupt: Preventing invalid write on metadata (overlaps with qcow2_header); further corruption events will be suppressed
write failed: Input/output error
*** done