On Wed, Apr 18, 2018 at 10:55:50AM +1000, David Gibson wrote:
> On Tue, Apr 17, 2018 at 06:53:17PM +0530, Balamuruhan S wrote:
> > expected_downtime value is not accurate with dirty_pages_rate * page_size,
> > using ram_bytes_remaining would yeild it correct.
>
> This commit message hasn't been changed since v1, but the patch is
> doing something completely different. I think most of the info from
> your cover letter needs to be in here.
>
> >
> > Signed-off-by: Balamuruhan S <bal...@linux.vnet.ibm.com>
> > ---
> > migration/migration.c | 6 +++---
> > migration/migration.h | 1 +
> > 2 files changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/migration/migration.c b/migration/migration.c
> > index 52a5092add..4d866bb920 100644
> > --- a/migration/migration.c
> > +++ b/migration/migration.c
> > @@ -614,7 +614,7 @@ static void populate_ram_info(MigrationInfo *info,
> > MigrationState *s)
> > }
> >
> > if (s->state != MIGRATION_STATUS_COMPLETED) {
> > - info->ram->remaining = ram_bytes_remaining();
> > + info->ram->remaining = s->ram_bytes_remaining;
> > info->ram->dirty_pages_rate = ram_counters.dirty_pages_rate;
> > }
> > }
> > @@ -2227,6 +2227,7 @@ static void migration_update_counters(MigrationState
> > *s,
> > transferred = qemu_ftell(s->to_dst_file) - s->iteration_initial_bytes;
> > time_spent = current_time - s->iteration_start_time;
> > bandwidth = (double)transferred / time_spent;
> > + s->ram_bytes_remaining = ram_bytes_remaining();
> > s->threshold_size = bandwidth * s->parameters.downtime_limit;
> >
> > s->mbps = (((double) transferred * 8.0) /
> > @@ -2237,8 +2238,7 @@ static void migration_update_counters(MigrationState
> > *s,
> > * recalculate. 10000 is a small enough number for our purposes
> > */
> > if (ram_counters.dirty_pages_rate && transferred > 10000) {
> > - s->expected_downtime = ram_counters.dirty_pages_rate *
> > - qemu_target_page_size() / bandwidth;
> > + s->expected_downtime = s->ram_bytes_remaining / bandwidth;
> > }
..but more importantly, I still think this change is bogus. expected
downtime is not the same thing as remaining ram / bandwidth.
> >
> > qemu_file_reset_rate_limit(s->to_dst_file);
> > diff --git a/migration/migration.h b/migration/migration.h
> > index 8d2f320c48..8584f8e22e 100644
> > --- a/migration/migration.h
> > +++ b/migration/migration.h
> > @@ -128,6 +128,7 @@ struct MigrationState
> > int64_t downtime_start;
> > int64_t downtime;
> > int64_t expected_downtime;
> > + int64_t ram_bytes_remaining;
> > bool enabled_capabilities[MIGRATION_CAPABILITY__MAX];
> > int64_t setup_time;
> > /*
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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