Hi Dmitry,
Thanks for the quick response! Yes, I was calling rte_eth_dev_rx_intr_enable —
I just tried re-arming interrupts before each call to epoll and my initial
experiment shows that fixes the issue.
You are right that l3fwd-power does the re-arming as well. If possible, it
would be helpful to have a comment in that example code about the re-arming
since the impression I got from quickly looking at the l3fwd-power code is that
interrupts are turned off because the app wants to poll for a threshold of time
before “giving up” and turning interrupts back on again. I’m happy to open a
pull request to add this comment, too, if you prefer.
Thanks again for your help!
Jack
> On Nov 1, 2021, at 12:46 AM, Dmitry Kozlyuk <dmitry.kozl...@gmail.com> wrote:
>
> 2021-10-31 22:50 (UTC-0700), Jack Humphries:
>> Hi folks,
>>
>> Hope all are well. I’m trying to enable interrupts in DPDK so that my
>> network receive thread can sleep on an epoll until packets arrive. I am
>> using the ixgbe kernel driver and igb_uio userspace driver with an Intel
>> 82599ES 10Gbps NIC.
>>
>> I'm doing roughly the following to enable the interrupts, but the epoll
>> never indicates that packets have arrived. The thread only handles packets
>> when the epoll times out. I don't even see interrupts arrive from the device
>> when monitoring /proc/interrupts.
>>
>> port_conf.intr_conf.rxq = 1;
>>
>> ...
>>
>> CHECK_EQ(rte_eth_dev_rx_intr_ctl_q(kPort, kQueue, RTE_EPOLL_PER_THREAD,
>> RTE_INTR_EVENT_ADD, nullptr),
>> 0);
>> CHECK_EQ(rte_eth_dev_rx_intr_enable(kPort, kQueue), 0);
>>
>> ...
>>
>> rte_epoll_event event;
>> while (true) {
>> int n = rte_epoll_wait(RTE_EPOLL_PER_THREAD, &event, /*maxevents=*/1,
>> /*timeout=*/1000);
>> if (n == 0) {
>> // Timeout expired.
>> } else {
>> // Received RX interrupt.
>> }
>> }
>>
>> Given that I don't see anything coming through in /proc/interrupts, I am
>> going to start digging through the ixgbe driver. However, I wanted to ask
>> here first to see if my setup is missing anything obvious. I based it
>> closely on the l3fwd-power example, though I haven't been able to get that
>> example up and running yet since my NIC only has one port plugged in right
>> now and the example requires two (COVID building restrictions).
>>
>> Thanks,
>> Jack Humphries
>
> Hi Jack,
>
> Have you called rte_eth_dev_rx_intr_enable(port_id, queue_id)?
>
> Not sure about ixgbe, but vmxnet3 also requires rearming interrupts with it
> on each iteration before rte_epoll_wait().
> This is what l3fwd-power does by the way (see turn_on_off_intr() function).
>
> + ixgbe maintainer just in case.
