Am 25.07.2018 um 17:57 hat Peter Krempa geschrieben:
> This series adds support for starting and hotplug of disks with
> -blockdev/blockdev-add.
>
> Blockjobs are not supported and thus the last patch should not be
> applied yet as some refactoring of the jobs is required.
>
> At the beginning of the series there are a few cleanup patches which may
> be pushed even at this point.
>
> The main reason this is in RFC state is that block stats reporting does
> not work.
>
> The following command:
>
> {"execute":"query-blockstats","arguments":{"query-nodes":true}}
query-nodes was added in commit f71eaa74c0b by Fam and Max, CCed. I'm
not sure what it was needed for at all and the commit message doesn't
help with that, but I suppose the addition was related to
wr_highest_offset (see below).
> Returns no reasonable data:
>
> {
> "stats": {
> "flush_total_time_ns": 0,
> "wr_highest_offset": 0,
> "wr_total_time_ns": 0,
> "failed_wr_operations": 0,
> "failed_rd_operations": 0,
> "wr_merged": 0,
> "wr_bytes": 0,
> "timed_stats": [
>
> ],
> "failed_flush_operations": 0,
> "account_invalid": false,
> "rd_total_time_ns": 0,
> "flush_operations": 0,
> "wr_operations": 0,
> "rd_merged": 0,
> "rd_bytes": 0,
> "invalid_flush_operations": 0,
> "account_failed": false,
> "rd_operations": 0,
> "invalid_wr_operations": 0,
> "invalid_rd_operations": 0
> },
> "node-name": "libvirt-7-storage"
> },
> {
> "parent": {
> "stats": {
> "flush_total_time_ns": 0,
> "wr_highest_offset": 0,
> "wr_total_time_ns": 0,
> "failed_wr_operations": 0,
> "failed_rd_operations": 0,
> "wr_merged": 0,
> "wr_bytes": 0,
> "timed_stats": [
>
> ],
> "failed_flush_operations": 0,
> "account_invalid": false,
> "rd_total_time_ns": 0,
> "flush_operations": 0,
> "wr_operations": 0,
> "rd_merged": 0,
> "rd_bytes": 0,
> "invalid_flush_operations": 0,
> "account_failed": false,
> "rd_operations": 0,
> "invalid_wr_operations": 0,
> "invalid_rd_operations": 0
> },
> "node-name": "libvirt-7-storage"
> },
> "stats": {
> "flush_total_time_ns": 0,
> "wr_highest_offset": 0,
> "wr_total_time_ns": 0,
> "failed_wr_operations": 0,
> "failed_rd_operations": 0,
> "wr_merged": 0,
> "wr_bytes": 0,
> "timed_stats": [
>
> ],
> "failed_flush_operations": 0,
> "account_invalid": false,
> "rd_total_time_ns": 0,
> "flush_operations": 0,
> "wr_operations": 0,
> "rd_merged": 0,
> "rd_bytes": 0,
> "invalid_flush_operations": 0,
> "account_failed": false,
> "rd_operations": 0,
> "invalid_wr_operations": 0,
> "invalid_rd_operations": 0
> },
> "node-name": "libvirt-7-format"
> },
>
> the 'libvirt-7-storage' and 'libvirt-7-format' nodes represent the ISO
> backing the CDROM used to boot the VM so reads were executed.
The only value that even exists that the node level is
wr_highest_offset. All the other stats are only accounted at the device
level, so we can't return anything meaningful here.
> In the old approach when we use -drive and query-nodes is false the
> output looks like this:
>
> {
> "device": "drive-ide0-0-0",
> "parent": {
> "stats": {
> "flush_total_time_ns": 0,
> "wr_highest_offset": 0,
> "wr_total_time_ns": 0,
> "failed_wr_operations": 0,
> "failed_rd_operations": 0,
> "wr_merged": 0,
> "wr_bytes": 0,
> "timed_stats": [
>
> ],
> "failed_flush_operations": 0,
> "account_invalid": false,
> "rd_total_time_ns": 0,
> "flush_operations": 0,
> "wr_operations": 0,
> "rd_merged": 0,
> "rd_bytes": 0,
> "invalid_flush_operations": 0,
> "account_failed": false,
> "rd_operations": 0,
> "invalid_wr_operations": 0,
> "invalid_rd_operations": 0
> },
> "node-name": "#block080"
> },
> "stats": {
> "flush_total_time_ns": 0,
> "wr_highest_offset": 0,
> "wr_total_time_ns": 0,
> "failed_wr_operations": 0,
> "failed_rd_operations": 0,
> "wr_merged": 0,
> "wr_bytes": 0,
> "timed_stats": [
>
> ],
> "failed_flush_operations": 0,
> "account_invalid": true,
> "rd_total_time_ns": 204236271,
> "flush_operations": 0,
> "wr_operations": 0,
> "rd_merged": 0,
> "rd_bytes": 30046628,
> "invalid_flush_operations": 0,
> "account_failed": true,
> "idle_time_ns": 18766797619,
> "rd_operations": 14680,
> "invalid_wr_operations": 0,
> "invalid_rd_operations": 0
> },
> "node-name": "#block152"
> },
>
> I also get all zeroes when I use 'query-nodes' true on a machine started
> with -drive.
>
> Without the stats we'd not achieve feature parity unfortunately.
>
> Kevin, could you please have a look?
As the information you're interested in is device-level information,
keep using query-nodes=false and identify which device it is for with
the 'device' field (the result contains a 'node-name', but this is not
suitable to identify the device when there are two users of the same
node).
Kevin
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