Re: [PATCH 5/5] migration: Print expected-downtime on completion

[Juan Quintela]

Joao Martins <joao.m.martins@oracle.com> wrote:
> Right now, migration statistics either print downtime or expected
> downtime depending on migration completing of in progress. Also in the
> beginning of migration by printing the downtime limit as expected
> downtime, when estimation is not available.
>
> The pending_size is private in migration iteration and not necessarily
> accessible outside. Given the non-determinism of the switchover cost, it
> can be useful to understand if the downtime was far off from the one
> detected by the migration algoritm, thus print the resultant downtime
> alongside its estimation.
>
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>

I see that "part" of this series is on the downtime series by Peter.
I have merged them (they are tracepoints, we can change them when
needed).

But this one is not on that series.

Should we continue and send a patch for it?

Later, Juan.


> ---
>  migration/migration.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/migration/migration.c b/migration/migration.c
> index dec6c88fbff9..f08f65b4b1c3 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -943,6 +943,10 @@ static void populate_time_info(MigrationInfo *info, 
> MigrationState *s)
>      if (s->state == MIGRATION_STATUS_COMPLETED) {
>          info->has_total_time = true;
>          info->total_time = s->total_time;
> +        if (s->expected_downtime) {
> +            info->has_expected_downtime = true;
> +            info->expected_downtime = s->expected_downtime;
> +        }
>      } else {
>          info->has_total_time = true;
>          info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) -
> @@ -2844,6 +2848,10 @@ static MigIterateState 
> migration_iteration_run(MigrationState *s)
>  
>      if ((!pending_size || pending_size < s->threshold_size) && 
> can_switchover) {
>          trace_migration_thread_low_pending(pending_size);
> +        if (s->threshold_size) {
> +            s->expected_downtime = (pending_size * 
> s->parameters.downtime_limit) /
> +                                   s->threshold_size;
> +        }
>          migration_completion(s);
>          return MIG_ITERATE_BREAK;
>      }