[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH v2] migration/throttle: Add cpu-throttle-tailslow migration p
From: |
zhukeqian |
Subject: |
Re: [PATCH v2] migration/throttle: Add cpu-throttle-tailslow migration parameter |
Date: |
Wed, 1 Apr 2020 09:27:17 +0800 |
User-agent: |
Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 |
Hi Eric,
On 2020/3/31 23:03, Eric Blake wrote:
> On 3/15/20 11:29 PM, Keqian Zhu wrote:
>> At the tail stage of throttling, the Guest is very sensitive to
>> CPU percentage while the @cpu-throttle-increment is excessive
>> usually at tail stage.
>>
>> If this parameter is true, we will compute the ideal CPU percentage
>> used by the Guest, which may exactly makes dirty rate to be dirty
>> rate threshold. Then we will choose a smaller throttle increment
>> between the one specified by @cpu-throttle-increment and the one
>> generated by ideal CPU percentage.
>>
>> Therefore, it is compatible to traditional throttling, meanwhile
>> the throttle increment won't be excessive at tail stage. This may
>> make migration time longer, and is disabled by default.
>>
>> Signed-off-by: Keqian Zhu <address@hidden>
>> ---
>> Cc: Juan Quintela <address@hidden>
>> Cc: "Dr. David Alan Gilbert" <address@hidden>
>> Cc: Eric Blake <address@hidden>
>> Cc: Markus Armbruster <address@hidden>
>> ---
>
>> +++ b/qapi/migration.json
>> @@ -552,6 +552,21 @@
>> # auto-converge detects that migration is not
>> making
>> # progress. The default value is 10. (Since 2.7)
>> #
>> +# @cpu-throttle-tailslow: Make CPU throttling slower at tail stage
>> +# At the tail stage of throttling, the Guest is very
>> +# sensitive to CPU percentage while the
>> @cpu-throttle
>> +# -increment is excessive usually at tail stage.
>> +# If this parameter is true, we will compute the
>> ideal
>> +# CPU percentage used by the Guest, which may
>> exactly
>> +# makes dirty rate to be dirty rate threshold. Then
>> we
>
> Grammar is off here, but I don't know if you meant "which may exactly make
> the dirty rate match the dirty rate threshold" or something else.
>
yep, this is what I want to express. I will correct it in v3. Thanks.
>> +# will choose a smaller throttle increment between
>> the
>> +# one specified by @cpu-throttle-increment and the
>> one
>> +# generated by ideal CPU percentage.
>> +# Therefore, it is compatible to traditional
>> throttling,
>> +# meanwhile the throttle increment won't be
>> excessive
>> +# at tail stage.
>> +# The default value is false. (Since 5.0)
>
> Is this a bug-fix that must make it into 5.0? It seems more like a feature
> addition, at which point listing it for 5.1 is probably a better idea.
>
Thanks for figuring it out.
This patch is sent out when v5.0 is not released.
I will correct it in v3.
Thanks,
Keqian