Re: [Qemu-devel] [PATCH v16 04/14] migration: Abstract the number of bytes sent

[Dr. David Alan Gilbert]

* Juan Quintela (address@hidden) wrote:
> Right now we use the "position" inside the QEMUFile, but things like
> RDMA already do weird things to be able to maintain that counter
> right, and multifd will have some similar problems.
> 
> Signed-off-by: Juan Quintela <address@hidden>

Reviewed-by: Dr. David Alan Gilbert <address@hidden>

> ---
>  migration/migration.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index d3e6da9bfe..264f3ce84e 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -2704,9 +2704,15 @@ static MigThrError 
> migration_detect_error(MigrationState *s)
>      }
>  }
>  
> +/* How many bytes have we transferred since the beggining of the migration */
> +static uint64_t migration_total_bytes(MigrationState *s)
> +{
> +    return qemu_ftell(s->to_dst_file);
> +}
> +
>  static void migration_calculate_complete(MigrationState *s)
>  {
> -    uint64_t bytes = qemu_ftell(s->to_dst_file);
> +    uint64_t bytes = migration_total_bytes(s);
>      int64_t end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
>      int64_t transfer_time;
>  
> @@ -2729,13 +2735,15 @@ static void migration_update_counters(MigrationState 
> *s,
>                                        int64_t current_time)
>  {
>      uint64_t transferred, time_spent;
> +    uint64_t current_bytes; /* bytes transferred since the beginning */
>      double bandwidth;
>  
>      if (current_time < s->iteration_start_time + BUFFER_DELAY) {
>          return;
>      }
>  
> -    transferred = qemu_ftell(s->to_dst_file) - s->iteration_initial_bytes;
> +    current_bytes = migration_total_bytes(s);
> +    transferred = current_bytes - s->iteration_initial_bytes;
>      time_spent = current_time - s->iteration_start_time;
>      bandwidth = (double)transferred / time_spent;
>      s->threshold_size = bandwidth * s->parameters.downtime_limit;
> @@ -2754,7 +2762,7 @@ static void migration_update_counters(MigrationState *s,
>      qemu_file_reset_rate_limit(s->to_dst_file);
>  
>      s->iteration_start_time = current_time;
> -    s->iteration_initial_bytes = qemu_ftell(s->to_dst_file);
> +    s->iteration_initial_bytes = current_bytes;
>  
>      trace_migrate_transferred(transferred, time_spent,
>                                bandwidth, s->threshold_size);
> -- 
> 2.17.1
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK