Re: [PATCH 2/8] qapi/migration: Introduce vcpu-dirty-limit parameters

[Peter Xu]

On Sat, Jul 23, 2022 at 03:49:14PM +0800, huangy81@chinatelecom.cn wrote:
> From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
> 
> Introduce "vcpu-dirty-limit" migration parameter used
> to limit dirty page rate during live migration.
> 
> "vcpu-dirty-limit" and "x-vcpu-dirty-limit-period" are
> two dirty-limit-related migration parameters, which can
> be set before and during live migration by qmp
> migrate-set-parameters.
> 
> This two parameters are used to help implement the dirty
> page rate limit algo of migration.
> 
> Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
> ---
>  migration/migration.c | 14 ++++++++++++++
>  monitor/hmp-cmds.c    |  8 ++++++++
>  qapi/migration.json   | 18 +++++++++++++++---
>  3 files changed, 37 insertions(+), 3 deletions(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 7b19f85..ed1a47b 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -117,6 +117,7 @@
>  #define DEFAULT_MIGRATE_ANNOUNCE_STEP    100
>  
>  #define DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT_PERIOD     500     /* ms */
> +#define DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT            1       /* MB/s */

This default value also looks a bit weird.. why 1MB/s?  Thanks,

-- 
Peter Xu