Re: [Qemu-devel] [PATCH v6 07/25] migration: introduce icount field for snapshots

[Markus Armbruster]

Pavel Dovgalyuk <address@hidden> writes:

> Saving icount as a parameters of the snapshot allows navigation between
> them in the execution replay scenario.
> This information can be used for finding a specific snapshot for rewinding
> the recorded execution to the specific moment of the time.
> E.g., 'reverse step' action needs to load the nearest snapshot which is
> prior to the current moment of time .
>
> Signed-off-by: Pavel Dovgalyuk <address@hidden>
[...]
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 4c7a37a..456af87 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -26,13 +26,16 @@
>  #
>  # @vm-clock-nsec: fractional part in nano seconds to be used with 
> vm-clock-sec
>  #
> +# @icount: current instruction count for execution record/replay (since 3.1)
> +#

Suggest to document clearly when this member is present.

>  # Since: 1.3
>  #
>  ##
>  { 'struct': 'SnapshotInfo',
>    'data': { 'id': 'str', 'name': 'str', 'vm-state-size': 'int',
>              'date-sec': 'int', 'date-nsec': 'int',
> -            'vm-clock-sec': 'int', 'vm-clock-nsec': 'int' } }
> +            'vm-clock-sec': 'int', 'vm-clock-nsec': 'int',
> +            '*icount': 'int' } }
>  
>  ##
>  # @ImageInfoSpecificQCow2EncryptionBase:
> diff --git a/qapi/block.json b/qapi/block.json
> index 11f01f2..a6396a9 100644
> --- a/qapi/block.json
> +++ b/qapi/block.json
> @@ -176,7 +176,8 @@
>  #                    "date-sec": 1000012,
>  #                    "date-nsec": 10,
>  #                    "vm-clock-sec": 100,
> -#                    "vm-clock-nsec": 20
> +#                    "vm-clock-nsec": 20,
> +#                    "icount": 220414
>  #      }
>  #    }
>  #