From: Igor Redko <[email protected]> To get this estimation we must divide pending_size by bandwidth according to description of expected-downtime ("qmp-commands.hx:3246"): "expected-downtime": only present while migration is active total amount in ms for downtime that was calculated on the last bitmap round (json-int)
Previous version was just wrong because dirty_bytes_rate and bandwidth are measured in Bytes/ms, so dividing first by second we get some dimensionless quantity. As it said in description above this value is showed during active migration phase and recalculated only after transferring all memory and if this process took more than 1 sec. So maybe just nobody noticed that bug. Signed-off-by: Igor Redko <[email protected]> Reviewed-by: Anna Melekhova <[email protected]> Signed-off-by: Denis V. Lunev <[email protected]> CC: Juan Quintela <[email protected]> CC: Amit Shah <[email protected]> --- migration/migration.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/migration/migration.c b/migration/migration.c index 662e77e..d55d545 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -994,7 +994,7 @@ static void *migration_thread(void *opaque) /* if we haven't sent anything, we don't want to recalculate 10000 is a small enough number for our purposes */ if (s->dirty_bytes_rate && transferred_bytes > 10000) { - s->expected_downtime = s->dirty_bytes_rate / bandwidth; + s->expected_downtime = pending_size / bandwidth; } qemu_file_reset_rate_limit(s->file); -- 2.1.4
