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