On 03/10/2019 14:23, Loftus, Ciara wrote:
>
>
>> -----Original Message-----
>> From: Stephen Hemminger <step...@networkplumber.org>
>> Sent: Monday 30 September 2019 18:12
>> To: Loftus, Ciara <ciara.lof...@intel.com>
>> Cc: dev@dpdk.org; Ye, Xiaolong <xiaolong...@intel.com>; Laatz, Kevin
>> <kevin.la...@intel.com>; Richardson, Bruce <bruce.richard...@intel.com>
>> Subject: Re: [dpdk-dev] [PATCH v2 2/3] net/af_xdp: support pinning of IRQs
>>
>> On Mon, 30 Sep 2019 16:42:04 +0000
>> Ciara Loftus <ciara.lof...@intel.com> wrote:
>>
>>> +/* drivers supported for the queue_irq option */
>>> +enum supported_drivers {
>>> + I40E_DRIVER,
>>> + IXGBE_DRIVER,
>>> + MLX5_DRIVER,
>>> + NUM_DRIVERS
>>> +};
>>
>> Anything device specific like this raises a red flag to me.
>>
>> This regex etc, seems like a huge hack. Is there a better way using
>> irqbalance and smp_affinity in kernel drivers?
>>
>> NACK
>
> Hi Stephen,
>
> Thanks for looking at the patch. I understand your concern however
> unfortunately I haven't been able to identify a way to achieve the desired
> outcome by using your suggestions of irqbalance and smp_affinity. Did you
> have something specific in mind or are aware of any generic way of retrieving
> interrupt numbers for NICs regardless of vendor or range?
>
> I think this feature is really important for the usability of this PMD.
> Without it, to configure the IRQs the user has to open up /proc/interrupts,
> trawl through it and identify the correct IRQ number for their given NIC and
> qid (the format for which is unlikely to be known off-hand), and manually pin
> them by writing the appropriate values in the appropriate format to the
> appropriate file - prone to error if not automated IMO.
> If the user fails to set the affinity it's probably fine for a single pmd,
> however with multiple pmds all irqs will by default land on core 0 and lead
> to terrible performance.
>
> It should be possible to rework the code to remove the regexes and use a
> direct string compare. Would that make the solution more palatable?
>
> Let me know what you think.
>
> Thanks,
> Ciara
>
Assuming there is no easier way to co-relate an ethernet device with an
interrupt, to make the strcmp's go away. My preference is for DPDK to take care
of it's rqmts - even in a less-that-ideal way, in preference to asking a user
to figure it out.
Ray K
