Re: [PATCH v2 6/7] migration/multifd: Add zero pages and zero bytes counter to migration status interface.

[Markus Armbruster <armbru@redhat.com>]

Hao Xiang <hao.xiang@bytedance.com> writes:

> This change extends the MigrationStatus interface to track zero pages
> and zero bytes counter.
>
> Signed-off-by: Hao Xiang <hao.xiang@bytedance.com>
> ---
>  migration/migration-hmp-cmds.c      |  4 ++++
>  migration/migration.c               |  2 ++
>  qapi/migration.json                 | 15 ++++++++++++++-
>  tests/migration/guestperf/engine.py |  2 ++
>  4 files changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
> index 7e96ae6ffd..abe035c9f2 100644
> --- a/migration/migration-hmp-cmds.c
> +++ b/migration/migration-hmp-cmds.c
> @@ -111,6 +111,10 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict)
>                         info->ram->normal);
>          monitor_printf(mon, "normal bytes: %" PRIu64 " kbytes\n",
>                         info->ram->normal_bytes >> 10);
> +        monitor_printf(mon, "zero: %" PRIu64 " pages\n",
> +                       info->ram->zero);
> +        monitor_printf(mon, "zero bytes: %" PRIu64 " kbytes\n",
> +                       info->ram->zero_bytes >> 10);
>          monitor_printf(mon, "dirty sync count: %" PRIu64 "\n",
>                         info->ram->dirty_sync_count);
>          monitor_printf(mon, "page size: %" PRIu64 " kbytes\n",
> diff --git a/migration/migration.c b/migration/migration.c
> index ab21de2cad..1968ea7075 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -1112,6 +1112,8 @@ static void populate_ram_info(MigrationInfo *info, MigrationState *s)
>      info->ram->skipped = 0;
>      info->ram->normal = stat64_get(&mig_stats.normal_pages);
>      info->ram->normal_bytes = info->ram->normal * page_size;
> +    info->ram->zero = stat64_get(&mig_stats.zero_pages);
> +    info->ram->zero_bytes = info->ram->zero * page_size;
>      info->ram->mbps = s->mbps;
>      info->ram->dirty_sync_count =
>          stat64_get(&mig_stats.dirty_sync_count);
> diff --git a/qapi/migration.json b/qapi/migration.json
> index e2450b92d4..892875da18 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -63,6 +63,10 @@
>  #     between 0 and @dirty-sync-count * @multifd-channels.  (since
>  #     7.1)
>  #
> +# @zero: number of zero pages (since 9.0)
> +#
> +# @zero-bytes: number of zero bytes sent (since 9.0)

Awfully terse.  How are these two related?

Recommend to name the first one @zero-pages.

> +#
>  # Features:
>  #
>  # @deprecated: Member @skipped is always zero since 1.5.3
> @@ -81,7 +85,8 @@
>             'multifd-bytes': 'uint64', 'pages-per-second': 'uint64',
>             'precopy-bytes': 'uint64', 'downtime-bytes': 'uint64',
>             'postcopy-bytes': 'uint64',
> -           'dirty-sync-missed-zero-copy': 'uint64' } }
> +           'dirty-sync-missed-zero-copy': 'uint64',
> +           'zero': 'int', 'zero-bytes': 'int' } }

Please use 'size' for byte counts such as @zero-bytes.

>  
>  ##
>  # @XBZRLECacheStats:
> @@ -332,6 +337,8 @@
>  #           "duplicate":123,
>  #           "normal":123,
>  #           "normal-bytes":123456,
> +#           "zero":123,
> +#           "zero-bytes":123456,
>  #           "dirty-sync-count":15
>  #         }
>  #      }
> @@ -358,6 +365,8 @@
>  #             "duplicate":123,
>  #             "normal":123,
>  #             "normal-bytes":123456,
> +#             "zero":123,
> +#             "zero-bytes":123456,
>  #             "dirty-sync-count":15
>  #          }
>  #       }
> @@ -379,6 +388,8 @@
>  #             "duplicate":123,
>  #             "normal":123,
>  #             "normal-bytes":123456,
> +#             "zero":123,
> +#             "zero-bytes":123456,
>  #             "dirty-sync-count":15
>  #          },
>  #          "disk":{
> @@ -405,6 +416,8 @@
>  #             "duplicate":10,
>  #             "normal":3333,
>  #             "normal-bytes":3412992,
> +#             "zero":3333,
> +#             "zero-bytes":3412992,
>  #             "dirty-sync-count":15
>  #          },
>  #          "xbzrle-cache":{
> diff --git a/tests/migration/guestperf/engine.py b/tests/migration/guestperf/engine.py
> index 608d7270f6..75315b99b7 100644
> --- a/tests/migration/guestperf/engine.py
> +++ b/tests/migration/guestperf/engine.py
> @@ -92,6 +92,8 @@ def _migrate_progress(self, vm):
>                  info["ram"].get("skipped", 0),
>                  info["ram"].get("normal", 0),
>                  info["ram"].get("normal-bytes", 0),
> +                info["ram"].get("zero", 0);
> +                info["ram"].get("zero-bytes", 0);
>                  info["ram"].get("dirty-pages-rate", 0),
>                  info["ram"].get("mbps", 0),
>                  info["ram"].get("dirty-sync-count", 0)