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Re: [PATCH v10 2/3] cpu-throttle: implement virtual CPU throttle
From: |
Markus Armbruster |
Subject: |
Re: [PATCH v10 2/3] cpu-throttle: implement virtual CPU throttle |
Date: |
Wed, 15 Dec 2021 08:15:50 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) |
huangy81@chinatelecom.cn writes:
> From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
>
> Setup a negative feedback system when vCPU thread
> handling KVM_EXIT_DIRTY_RING_FULL exit by introducing
> throttle_us_per_full field in struct CPUState. Sleep
> throttle_us_per_full microseconds to throttle vCPU
> if dirtylimit is enabled.
>
> Start a thread to track current dirty page rates and
> tune the throttle_us_per_full dynamically untill current
> dirty page rate reach the quota.
>
> Introduce the util function in the header for dirtylimit
> implementation.
>
> Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
[...]
> diff --git a/qapi/migration.json b/qapi/migration.json
> index bbfd48c..ac5fa56 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -1850,6 +1850,25 @@
> { 'command': 'query-dirty-rate', 'returns': 'DirtyRateInfo' }
>
> ##
> +# @DirtyLimitInfo:
> +#
> +# Dirty page rate limit information of virtual CPU.
> +#
> +# @cpu-index: index of virtual CPU.
> +#
> +# @limit-rate: upper limit of dirty page rate for virtual CPU.
If I understand your code correctly, zero means unlimited. This is
undocumented.
In review of v9, I asked to "make @dirty-rate optional, present means
enable, absent means disable." Any particular reason for not doing it
that way?
> +#
> +# @current-rate: current dirty page rate for virtual CPU.
> +#
> +# Since: 7.0
> +#
> +##
> +{ 'struct': 'DirtyLimitInfo',
> + 'data': { 'cpu-index': 'int',
> + 'limit-rate': 'int64',
> + 'current-rate': 'int64' } }
> +
> +##
> # @snapshot-save:
> #
> # Save a VM snapshot
[...]