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Subject: Re: [PATCH next] softirq: enable MAX_SOFTIRQ_TIME tuning with sysctl
 max_softirq_time_usecs
To:     Thomas Gleixner <tglx@linutronix.de>
CC:     <corbet@lwn.net>, <mcgrof@kernel.org>,
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References: <f274f85a-bbb6-3e32-b293-1d5d7f27a98f@huawei.com>
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 <alpine.DEB.2.21.1906241141370.32342@nanos.tec.linutronix.de>
From:   Zhiqiang Liu <liuzhiqiang26@huawei.com>
Message-ID: <e870e089-efb6-53a7-4299-8468f2ba8852@huawei.com>
Date:   Mon, 24 Jun 2019 21:32:48 +0800
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On 2019/6/24 17:45, Thomas Gleixner wrote:
> Zhiqiang,
> 
> On Mon, 24 Jun 2019, Zhiqiang Liu wrote:
>> ?? 2019/6/24 0:38, Thomas Gleixner д??:
>>
>> Thanks again for your detailed advice.
>> As your said, the max_softirq_time_usecs setting without explaining the
>> relationship with CONFIG_HZ will give a false sense of controlability. And
>> the time accuracy of jiffies will result in a certain difference between the
>> max_softirq_time_usecs set value and the actual value, which is in one jiffies
>> range.
>>
>> I will add these infomation in the sysctl documentation and changelog in v2 patch.
> 
> Please make the sysctl milliseconds based. That's the closest approximation
> of useful units for this. This still has the same issues as explained
> before but it's not off by 3 orders of magitude anymore.
> 
> Thanks,
> 
> 	tglx
> 
Thanks for your suggestion.
I will adopt max_softirq_time_ms to replace MAX_SOFTIRQ_TIME in v2.