[prev in list] [next in list] [prev in thread] [next in thread] 

List:       dpdk-dev
Subject:    [dpdk-dev] interrupt mode issue for virtio device
From:       "Yan, Xiaoping (NSB - CN/Hangzhou)" <xiaoping.yan () nokia-sbell ! com>
Date:       2020-07-31 10:15:25
Message-ID: a05706c3a2fa4b5696d73c7b5db97495 () nokia-sbell ! com
[Download RAW message or body]

Hi,

I have a dpdk application run in interrupt mode(like examples\l3fwd-power) for a \
virtio device Network devices using DPDK-compatible driver
============================================
0000:00:04.0 'Virtio network device 1000' drv=vfio-pci unused=igb_uio

It works (application is waken up when packet come in) in some host infrastructure, \
but doesn't work ((application is NOT waken up when packet come in)) in some other. \
In the host where it doesn't work, I found the interrupt increases in cat \
/proc/interrupts for this device. It seems the fd in efds (value 34) mismatch the fds \
added to epfd (value 33) where my application is wating. The other 2 ports (they are \
sriov VF device) works normally. (gdb) print *(rte_eth_devices[0]->intr_handle)
$1 = {{vfio_dev_fd = 13, uio_cfg_fd = 13}, fd = 14, type = RTE_INTR_HANDLE_VFIO_MSIX, \
max_intr = 2, nb_efd = 1,  efd_counter_size = 0 '\000', efds = {34, 0 <repeats 31 \
                times>}, elist = {{status = 1, fd = 21, epfd = 33, epdata = {
        event = 2147483651, data = 0x0, cb_fun = 0x6c1b10 <eal_intr_proc_rxtx_intr>, \
                cb_arg = 0x7a592f8}}, {status = 0, fd = 0,
      epfd = 0, epdata = {event = 0, data = 0x0, cb_fun = 0x0, cb_arg = 0x0}} \
<repeats 31 times>}, intr_vec = 0x2ab525a0f80} (gdb) print \
*(rte_eth_devices[1]->intr_handle) $2 = {{vfio_dev_fd = 16, uio_cfg_fd = 16}, fd = \
17, type = RTE_INTR_HANDLE_VFIO_MSIX, max_intr = 2, nb_efd = 1,  efd_counter_size = 0 \
'\000', efds = {22, 0 <repeats 31 times>}, elist = {{status = 1, fd = 22, epfd = 33, \
                epdata = {
        event = 2147483651, data = 0x100, cb_fun = 0x6c1b10 \
                <eal_intr_proc_rxtx_intr>, cb_arg = 0x7a5c178}}, {status = 0, fd = 0,
      epfd = 0, epdata = {event = 0, data = 0x0, cb_fun = 0x0, cb_arg = 0x0}} \
<repeats 31 times>}, intr_vec = 0x2ab525a09c0} (gdb) print \
*(rte_eth_devices[2]->intr_handle) $3 = {{vfio_dev_fd = 19, uio_cfg_fd = 19}, fd = \
20, type = RTE_INTR_HANDLE_VFIO_MSIX, max_intr = 2, nb_efd = 1,  efd_counter_size = 0 \
'\000', efds = {23, 0 <repeats 31 times>}, elist = {{status = 1, fd = 23, epfd = 33, \
                epdata = {
        event = 2147483651, data = 0x200, cb_fun = 0x6c1b10 \
                <eal_intr_proc_rxtx_intr>, cb_arg = 0x7a59ab8}}, {status = 0, fd = 0,
      epfd = 0, epdata = {event = 0, data = 0x0, cb_fun = 0x0, cb_arg = 0x0}} \
<repeats 31 times>}, intr_vec = 0x2ab525a0400}

so although eventfd-count for 34 is increasing, my application is not waken up
# grep -r eventfd-count /proc/1910/fdinfo/
...
/proc/1910/fdinfo/28:eventfd-count: 0
/proc/1910/fdinfo/30:eventfd-count: 114b5da
/proc/1910/fdinfo/31:eventfd-count: 0
/proc/1910/fdinfo/34:eventfd-count: 2054

The epoll fd 33 seems doesn't include eventfd 34
# cat /proc/1910/fdinfo/33
pos: 0
flags: 02
mnt_id: 11
tfd: 21 events: 8000001b data: 7a59390 pos:0 ino:2514 sdev:b
tfd: 22 events: 8000001b data: 7a5c210 pos:0 ino:2514 sdev:b
tfd: 23 events: 8000001b data: 7a59b50 pos:0 ino:2514 sdev:b
tfd: 31 events: 8000001b data: 7fffffffe230 pos:0 ino:2514 sdev:b

My application register event like this(like examples\l3fwd-power):
rte_eth_dev_rx_intr_ctl_q(portid, queueid,RTE_EPOLL_PER_THREAD, RTE_INTR_EVENT_ADD, \
(void *)((uintptr_t)data));

I doubt the efds has changed after the register, but can't find how this could \
happen... Any idea please?


DPDK version in use: 18.05


I saw 1 commit in 19.05 might be relevant.(in my case, there is secondary dpdk \
process, my application is the primary process) Could you please confirm?

commit 1c8489da561be16ac73c6dab01db816af249713f
Author: Tiwei Bie <tiwei.bie@intel.com>
Date:   Mon Mar 25 12:12:15 2019 +0800

    net/virtio-user: fix multi-process support

    This patch fixes the multi-process support for virtio-user.
    Currently virtio-user just provides some limited secondary
    process supports. Only some basic operations can be done in
    secondary process on virtio-user port, e.g. getting port stats.
    Actions which will trigger the communication with vhost backend
    can't be done in secondary process for now, as the fds are
    not synced between processes. The processing of server mode
    devargs is also moved into virtio_user_dev_init().

    Fixes: cdb068f031c6 ("bus/vdev: scan by multi-process channel")
    Fixes: ee27edbe0c10 ("drivers/net: share vdev data to secondary process")
    Cc: stable@dpdk.org

    Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
    Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thank you.


Best regards
Yan Xiaoping


[prev in list] [next in list] [prev in thread] [next in thread]