Re: [PATCH v10 3/3] cpus-common: implement dirty page limit on virtual CPU

[Hyman Huang]

在 2021/12/15 15:37, Markus Armbruster 写道:
> huangy81@chinatelecom.cn writes:
>
> > From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
> >
> > Implement dirtyrate calculation periodically basing on
> > dirty-ring and throttle virtual CPU until it reachs the quota
> > dirty page rate given by user.
> >
> > Introduce qmp commands "vcpu-dirty-limit", "query-vcpu-dirty-limit"
> > to enable, disable, query dirty page limit for virtual CPU.
> >
> > Meanwhile, introduce corresponding hmp commands "vcpu_dirty_limit",
> > "info vcpu_dirty_limit" so developers can play with them easier.
> >
> > Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
>
> [...]
>
> > diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
> > index 96d0148..04879a2 100644
> > --- a/include/monitor/hmp.h
> > +++ b/include/monitor/hmp.h
> > @@ -131,6 +131,8 @@ void hmp_replay_delete_break(Monitor *mon, const QDict 
> > *qdict);
> >   void hmp_replay_seek(Monitor *mon, const QDict *qdict);
> >   void hmp_info_dirty_rate(Monitor *mon, const QDict *qdict);
> >   void hmp_calc_dirty_rate(Monitor *mon, const QDict *qdict);
> > +void hmp_info_vcpu_dirty_limit(Monitor *mon, const QDict *qdict);
> > +void hmp_vcpu_dirty_limit(Monitor *mon, const QDict *qdict);
> >   void hmp_human_readable_text_helper(Monitor *mon,
> >                                       HumanReadableText *(*qmp_handler)(Error 
> > **));
> >   
> > diff --git a/qapi/migration.json b/qapi/migration.json
> > index ac5fa56..7d8da4f 100644
> > --- a/qapi/migration.json
> > +++ b/qapi/migration.json
> > @@ -1869,6 +1869,50 @@
> >               'current-rate': 'int64' } }
> >   
> >   ##
> > +# @vcpu-dirty-limit:
> > +#
> > +# Set or cancel the upper limit of dirty page rate for a virtual CPU.
> > +#
> > +# Requires KVM with accelerator property "dirty-ring-size" set.
> > +# A virtual CPU's dirty page rate is a measure of its memory load.
> > +# To observe dirty page rates, use @calc-dirty-rate.
> > +#
> > +# @enable: true to enable, false to disable.
> > +#
> > +# @cpu-index: index of virtual CPU, default is all.
>
> Suggest
>
>      # @cpu-index: The vCPU to act upon (all by default).
>
> (I'm stealing this from trace.json)
>
> > +#
> > +# @dirty-rate: upper limit of dirty page rate for virtual CPU, to
> > +#              cancel dirty limit, this field will be ignored.
> > +#
> > +# Since: 7.0
> > +#
> > +# Example:
> > +#   {"execute": "vcpu-dirty-limit"}
> > +#    "arguments": { "enable": true,
> > +#                   "cpu-index": 1,
> > +#                   "dirty-rate": 200 } }
> > +#
> > +##
> > +{ 'command': 'vcpu-dirty-limit',
> > +  'data': { 'enable': 'bool',
> > +            '*cpu-index': 'uint64',
> > +            '*dirty-rate': 'uint64'} }
>
> Drop @enable, please.
>
> If @dirty-rate is present, set the limit to its value.
>
> If it's absent, cancel the limit.
Ok. Indeed, this is the simplest style. :)

So the final qmp format should be like:

case 1: setup vcpu 0 dirty page limit 100MB/s
vcpu-dirty-limit  cpu-index=0   dirty-rate=100MB/s

case 2: cancle vcpu 0 dirty page limit
vcpu-dirty-limit  cpu-index=0

I'll do that next version.

Thanks Markus very much

> > +
> > +##
> > +# @query-vcpu-dirty-limit:
> > +#
> > +# Returns information about all virtual CPU dirty limit if enabled.
> > +#
> > +# Since: 7.0
> > +#
> > +# Example:
> > +#   {"execute": "query-vcpu-dirty-limit"}
> > +#
> > +##
> > +{ 'command': 'query-vcpu-dirty-limit',
> > +  'returns': [ 'DirtyLimitInfo' ] }
> > +
> > +##
> >   # @snapshot-save:
> >   #
> >   # Save a VM snapshot

--
Best regard

Hyman Huang(黄勇)