new in v6:
- since clauses -> 4.0
- patch 9: qapi json cosmetic changes as suggested by Vladimir
- patch 9: proper "driver" field setting for host_device driver
v5: http://lists.nongnu.org/archive/html/qemu-devel/2018-10/msg06828.html
v4: http://lists.nongnu.org/archive/html/qemu-devel/2018-08/msg04308.html
v3: http://lists.nongnu.org/archive/html/qemu-devel/2018-06/msg03688.html
----
qmp query-blockstats provides stats info for write/read/flush ops.
Patches 1-7 implement the similar for discard (unmap) command for scsi
and ide disks.
Discard stat "unmap_ops / unmap_bytes" is supposed to account the ops that
have completed without an error.
However, discard operation is advisory. Specifically,
- common block layer ignores ENOTSUP error code.
That might be returned if the block driver does not support discard,
or discard has been configured to be ignored.
- format drivers such as qcow2 may ignore discard if they were configured
to ignore that, or if the corresponding area is already marked unused
(unallocated / zero clusters).
And what is actually useful is the number of bytes actually discarded
down on the host filesystem.
To achieve that, driver-specific statistics has been added to blockstats
(patch 9).
With patch 8, file-posix driver accounts discard operations on its level too.
query-blockstat result:
(note the difference between blockdevice unmap and file discard stats. qcow2
sends fewer ops down to the file as the clusters are actually unallocated
on qcow2 level)
{
"device": "drive-scsi0-0-0-0",
"node-name": "#block159",
"stats": {
> "invalid_unmap_operations": 0,
> "failed_unmap_operations": 0,
"wr_highest_offset": 13411688448,
"rd_total_time_ns": 2859566315,
"rd_bytes": 103182336,
"rd_merged": 0,
"flush_operations": 19,
"invalid_wr_operations": 0,
"flush_total_time_ns": 23111608,
"failed_rd_operations": 0,
"failed_flush_operations": 0,
"invalid_flush_operations": 0,
"timed_stats": [
],
"wr_merged": 0,
"wr_bytes": 1702912,
> "unmap_bytes": 11954954240,
> "unmap_operations": 865,
"idle_time_ns": 2669508623,
"account_invalid": true,
> "unmap_total_time_ns": 19698002,
"wr_operations": 143,
"failed_wr_operations": 0,
"rd_operations": 4816,
"account_failed": true,
> "unmap_merged": 0,
"wr_total_time_ns": 1262686124,
"invalid_rd_operations": 0
},
"parent": {
> "driver-specific": {
> "discard-nb-failed": 0,
> "discard-bytes-ok": 720896,
> "driver": "file",
> "discard-nb-ok": 8
> },
"node-name": "#block009",
"stats": {
[..]
}
}
},
{
"device": "floppy0",
Anton Nefedov (9):
qapi: group BlockDeviceStats fields
qapi: add unmap to BlockDeviceStats
block: add empty account cookie type
ide: account UNMAP (TRIM) operations
scsi: store unmap offset and nb_sectors in request struct
scsi: move unmap error checking to the complete callback
scsi: account unmap operations
file-posix: account discard operations
qapi: query-blockstat: add driver specific file-posix stats
qapi/block-core.json | 81 ++++++++++++++++++++++++++++++++------
include/block/accounting.h | 2 +
include/block/block.h | 1 +
include/block/block_int.h | 1 +
block.c | 9 +++++
block/accounting.c | 6 +++
block/file-posix.c | 60 ++++++++++++++++++++++++++--
block/qapi.c | 11 ++++++
hw/ide/core.c | 12 ++++++
hw/scsi/scsi-disk.c | 32 +++++++++------
tests/qemu-iotests/227.out | 18 +++++++++
11 files changed, 208 insertions(+), 25 deletions(-)
--
2.17.1