Re: [PATCH v8 2/3] Documentation: add a isolation strategy sysfs node for uacce

["yekai (A)" <yekai13@huawei.com>]

On 2022/9/9 16:27, Greg KH wrote:
> On Fri, Sep 02, 2022 at 03:13:03AM +0000, Kai Ye wrote:
>> Update documentation describing sysfs node that could help to
>> configure isolation strategy for users in the user space. And
>> describing sysfs node that could read the device isolated state.
>>
>> Signed-off-by: Kai Ye <yekai13@huawei.com>
>> ---
>>  Documentation/ABI/testing/sysfs-driver-uacce | 26 ++++++++++++++++++++
>>  1 file changed, 26 insertions(+)
>>
>> diff --git a/Documentation/ABI/testing/sysfs-driver-uacce b/Documentation/ABI/testing/sysfs-driver-uacce
>> index 08f2591138af..af5bc2f326d2 100644
>> --- a/Documentation/ABI/testing/sysfs-driver-uacce
>> +++ b/Documentation/ABI/testing/sysfs-driver-uacce
>> @@ -19,6 +19,32 @@ Contact:        linux-accelerators@lists.ozlabs.org
>>  Description:    Available instances left of the device
>>                  Return -ENODEV if uacce_ops get_available_instances is not provided
>>  
>> +What:           /sys/class/uacce/<dev_name>/isolate_strategy
>> +Date:           Sep 2022
>> +KernelVersion:  6.0
>> +Contact:        linux-accelerators@lists.ozlabs.org
>> +Description:    (RW) Configure the frequency size for the hardware error
>> +                isolation strategy. This size is a configured integer value.
>> +                The default is 0. The maximum value is 65535. This value is a
>> +                threshold based on your driver strategies.
> I do not understand what the units are here.
>
> How is anyone supposed to know what they are?

This unit is the number of times. Number of occurrences in a period, also means threshold.
If the number of device pci AER error exceeds the threshold in a time window, the device is
isolated. 

>> +                For example, in the hisilicon accelerator engine, first we will
>> +                time-stamp every slot AER error. Then check the AER error log
>> +                when the device AER error occurred. if the device slot AER error
>> +                count exceeds the preset the number of times in one hour, the
>> +                isolated state will be set to true. So the device will be
>> +                isolated. And the AER error log that exceed one hour will be
>> +                cleared. Of course, different strategies can be defined in
>> +                different drivers.
> So this file can contain values of different units depending on the
> different driver that creates it?  How is anyone supposed to know what
> it is and what it should be?
>
> This feels very loose, please define this much better so that it can be
> understood and maintained properly.
>
> thanks,
>
> greg k-h
> .
>
Yes,  We started out with the idea of not restricting the different drive,  only specifying the input and output.
Because we think different drivers require different processing  strategy.