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[Qemu-block] [PATCH v4 0/8] discard blockstats
From: |
Anton Nefedov |
Subject: |
[Qemu-block] [PATCH v4 0/8] discard blockstats |
Date: |
Tue, 21 Aug 2018 12:46:11 +0300 |
new in v4:
- patch 7: discard and write-zeroes code paths had been separated in
34fa110e: file-posix: Fix write_zeroes with unmap on block devices.
This patch now only accounts discards that come explicitly
through .bdrv_co_pdiscard handler.
- qapi 'Since' clauses changed 3.0 -> 3.1
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 1-6 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 8).
With patch 7, 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)
{
"return": [
{
"device": "drive-scsi0-0-0-0",
"parent": {
> "discard-bytes-ok": 262144,
> "discard-nb-ok": 4,
"stats": {
> "unmap_operations": 0,
> "unmap_merged": 0,
"flush_total_time_ns": 0,
"wr_highest_offset": 8111718400,
"wr_total_time_ns": 0,
"failed_wr_operations": 0,
"failed_rd_operations": 0,
"wr_merged": 0,
"wr_bytes": 0,
"timed_stats": [
],
> "failed_unmap_operations": 0,
"failed_flush_operations": 0,
"account_invalid": false,
"rd_total_time_ns": 0,
> "invalid_unmap_operations": 0,
"flush_operations": 0,
"wr_operations": 0,
> "unmap_bytes": 0,
"rd_merged": 0,
"rd_bytes": 0,
> "unmap_total_time_ns": 0,
"invalid_flush_operations": 0,
"account_failed": false,
"rd_operations": 0,
"invalid_wr_operations": 0,
"invalid_rd_operations": 0
},
"node-name": "#block012",
> "driver": "file",
> "discard-nb-failed": 0
},
"stats": {
> "unmap_operations": 860,
> "unmap_merged": 0,
"flush_total_time_ns": 21506733,
"wr_highest_offset": 13411741696,
"wr_total_time_ns": 2212749334,
"failed_wr_operations": 0,
"failed_rd_operations": 0,
"wr_merged": 0,
"wr_bytes": 3426304,
"timed_stats": [
],
> "failed_unmap_operations": 0,
"failed_flush_operations": 0,
"account_invalid": true,
"rd_total_time_ns": 3617478206,
> "invalid_unmap_operations": 0,
"flush_operations": 24,
"wr_operations": 309,
> "unmap_bytes": 11949633536,
"rd_merged": 0,
"rd_bytes": 141967360,
> "unmap_total_time_ns": 14871816,
[..]
Anton Nefedov (8):
qapi: group BlockDeviceStats fields
qapi: add unmap to BlockDeviceStats
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 | 82 +++++++++++++++++++++++++++++++++++++++-------
include/block/accounting.h | 1 +
include/block/block.h | 1 +
include/block/block_int.h | 1 +
block.c | 9 +++++
block/file-posix.c | 45 +++++++++++++++++++++++--
block/qapi.c | 11 +++++++
hw/ide/core.c | 12 +++++++
hw/scsi/scsi-disk.c | 29 +++++++++-------
tests/qemu-iotests/227.out | 18 ++++++++++
10 files changed, 184 insertions(+), 25 deletions(-)
--
2.7.4
- [Qemu-block] [PATCH v4 0/8] discard blockstats,
Anton Nefedov <=
- [Qemu-block] [PATCH v4 3/8] ide: account UNMAP (TRIM) operations, Anton Nefedov, 2018/08/21
- [Qemu-block] [PATCH v4 1/8] qapi: group BlockDeviceStats fields, Anton Nefedov, 2018/08/21
- [Qemu-block] [PATCH v4 2/8] qapi: add unmap to BlockDeviceStats, Anton Nefedov, 2018/08/21
- [Qemu-block] [PATCH v4 6/8] scsi: account unmap operations, Anton Nefedov, 2018/08/21
- [Qemu-block] [PATCH v4 5/8] scsi: move unmap error checking to the complete callback, Anton Nefedov, 2018/08/21
- [Qemu-block] [PATCH v4 4/8] scsi: store unmap offset and nb_sectors in request struct, Anton Nefedov, 2018/08/21
- [Qemu-block] [PATCH v4 7/8] file-posix: account discard operations, Anton Nefedov, 2018/08/21
- [Qemu-block] [PATCH v4 8/8] qapi: query-blockstat: add driver specific file-posix stats, Anton Nefedov, 2018/08/21