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Re: [Qemu-devel] [PATCH 2/4] migration: set dirty_pages_rate before auto
From: |
Peter Xu |
Subject: |
Re: [Qemu-devel] [PATCH 2/4] migration: set dirty_pages_rate before autoconverge logic |
Date: |
Thu, 25 May 2017 08:40:07 +0800 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Wed, May 24, 2017 at 05:10:01PM +0100, Felipe Franciosi wrote:
> Currently, a "period" in the RAM migration logic is at least a second
> long and accounts for what happened since the last period (or the
> beginning of the migration). The dirty_pages_rate counter is calculated
> at the end this logic.
>
> If the auto convergence capability is enabled from the start of the
> migration, it won't be able to use this counter the first time around.
> This calculates dirty_pages_rate as soon as a period is deemed over,
> which allows for it to be used immediately.
>
> Signed-off-by: Felipe Franciosi <address@hidden>
You fixed the indents as well, but imho it's okay.
Reviewed-by: Peter Xu <address@hidden>
> ---
> migration/ram.c | 17 ++++++++++-------
> 1 file changed, 10 insertions(+), 7 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index 36bf720..495ecbe 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -694,6 +694,10 @@ static void migration_bitmap_sync(RAMState *rs)
>
> /* more than 1 second = 1000 millisecons */
> if (end_time > rs->time_last_bitmap_sync + 1000) {
> + /* calculate period counters */
> + rs->dirty_pages_rate = rs->num_dirty_pages_period * 1000
> + / (end_time - rs->time_last_bitmap_sync);
> +
> if (migrate_auto_converge()) {
> /* The following detection logic can be refined later. For now:
> Check to see if the dirtied bytes is 50% more than the approx.
> @@ -702,15 +706,14 @@ static void migration_bitmap_sync(RAMState *rs)
> throttling */
> bytes_xfer_now = ram_bytes_transferred();
>
> - if (rs->dirty_pages_rate &&
> - (rs->num_dirty_pages_period * TARGET_PAGE_SIZE >
> + if ((rs->num_dirty_pages_period * TARGET_PAGE_SIZE >
> (bytes_xfer_now - rs->bytes_xfer_prev) / 2) &&
> - (rs->dirty_rate_high_cnt++ >= 2)) {
> + (rs->dirty_rate_high_cnt++ >= 2)) {
> trace_migration_throttle();
> rs->dirty_rate_high_cnt = 0;
> mig_throttle_guest_down();
> - }
> - rs->bytes_xfer_prev = bytes_xfer_now;
> + }
> + rs->bytes_xfer_prev = bytes_xfer_now;
> }
>
> if (migrate_use_xbzrle()) {
> @@ -723,8 +726,8 @@ static void migration_bitmap_sync(RAMState *rs)
> rs->iterations_prev = rs->iterations;
> rs->xbzrle_cache_miss_prev = rs->xbzrle_cache_miss;
> }
> - rs->dirty_pages_rate = rs->num_dirty_pages_period * 1000
> - / (end_time - rs->time_last_bitmap_sync);
> +
> + /* reset period counters */
> rs->time_last_bitmap_sync = end_time;
> rs->num_dirty_pages_period = 0;
> }
> --
> 1.9.5
>
--
Peter Xu
[Qemu-devel] [PATCH 3/4] migration: set bytes_xfer_* outside of autoconverge logic, Felipe Franciosi, 2017/05/24