Re: [RFC V2 net-next 1/3] ethtool: extend coalesce setting uAPI with CQE mode

[Huazhong Tan <tanhuazhong@huawei.com>]

On 2021/5/30 5:23, Jakub Kicinski wrote:
> On Sat, 29 May 2021 11:22:14 +0800 Huazhong Tan wrote:
>> diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
>> index 25131df..8e8c6b3 100644
>> --- a/Documentation/networking/ethtool-netlink.rst
>> +++ b/Documentation/networking/ethtool-netlink.rst
>> @@ -937,6 +937,8 @@ Kernel response contents:
>>     ``ETHTOOL_A_COALESCE_TX_USECS_HIGH``         u32     delay (us), high Tx
>>     ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES_HIGH``    u32     max packets, high Tx
>>     ``ETHTOOL_A_COALESCE_RATE_SAMPLE_INTERVAL``  u32     rate sampling interval
>> +  ``ETHTOOL_A_COALESCE_USE_CQE_TX``	       bool    timer reset in CQE, Tx
>> +  ``ETHTOOL_A_COALESCE_USE_CQE_RX``	       bool    timer reset in CQE, Rx
>>     ===========================================  ======  =======================
>>   
>>   Attributes are only included in reply if their value is not zero or the
>> @@ -975,6 +977,8 @@ Request contents:
>>     ``ETHTOOL_A_COALESCE_TX_USECS_HIGH``         u32     delay (us), high Tx
>>     ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES_HIGH``    u32     max packets, high Tx
>>     ``ETHTOOL_A_COALESCE_RATE_SAMPLE_INTERVAL``  u32     rate sampling interval
>> +  ``ETHTOOL_A_COALESCE_USE_CQE_TX``	       bool    timer reset in CQE, Tx
>> +  ``ETHTOOL_A_COALESCE_USE_CQE_RX``	       bool    timer reset in CQE, Rx
>>     ===========================================  ======  =======================
>>   
>>   Request is rejected if it attributes declared as unsupported by driver (i.e.
> Did you provide the theory of operation for CQE vs EQE mode somewhere,
> as I requested?


the definition of enum dim_cq_period_mode in include/linux/dim.h has

below comment:

/**
  * enum dim_cq_period_mode - Modes for CQ period count
  *
  * @DIM_CQ_PERIOD_MODE_START_FROM_EQE: Start counting from EQE
  * @DIM_CQ_PERIOD_MODE_START_FROM_CQE: Start counting from CQE (implies 
timer reset)
  * @DIM_CQ_PERIOD_NUM_MODES: Number of modes
  */


is this comment suitable? and add reference in 
Documentation/networking/ethtool-netlink.rst to

the comment in dim.h.


>> +	[ETHTOOL_A_COALESCE_USE_CQE_MODE_TX]	= { .type = NLA_U8 },
>> +	[ETHTOOL_A_COALESCE_USE_CQE_MODE_RX]	= { .type = NLA_U8 },
> Why not NLA_POLICY_MAX(NLA_U8, 1) ?


will fix it.


> Any chance you could split the patch into adding the new parameter
> to the callback and adding new attributes?


ok, will split it in the next version.


Thanks.


> .