[dpdk-dev] [RFC PATCH 0/5] Introduce low-latency one-shot rx interrupt into DPDK with polling/interrupt switch control example

[Danny Zhou <danny.zhou@intel.com>]

DPDK interrupt notification/handling mechanism is based on UIO with
below limitation:
1) It is designed to handle LSC interrupt only with inefficient
suspended pthread wakeup procedure (e.g. UIO wakes up LSC interrupt
handling thread which then wakes up DPDK polling thread). In this way,
it introduces non-deterministic wakeup latency for DPDK polling thread
as well as packet latency if it is used to handle Rx interrupt.
2) UIO only supports a single interrupt vector which has to been shared
by LSC interrupt and interrupts assigned to dedicated rx queues.
 
This patchset includes below features:
1) Enable one-shot rx queue interrupt in ixgbe PMD for PF as well as VF.
2) Build on top of the VFIO mechanism instead of UIO, so it could support
up to 64 interrupt vectors for rx queue interrupts.
3) Have 1 DPDK polling thread handle per Rx queue interrupt with a
dedicated VFIO eventfd, which eliminates non-deterministic pthread wakeup
latency in user space.
4) Demonstrate interrupts control APIs and userspace NAIP-like
polling/interrupt switch algorithms in L3fwd-power example.

Danny Zhou (5):
  ethdev: add rx interrupt enable/disable functions
  ixgbe: enable rx queue interrupts
  eal: add per rx queue interrupt handling based on VFIO
  L3fwd-power: enable one-shot rx interrupt and polling/interrupt mode  
      switch
  ixgbe: enable rx queue interrupts for VF

 examples/l3fwd-power/main.c                        | 171 +++++++---
 lib/librte_eal/common/include/rte_eal.h            |   9 +
 lib/librte_eal/linuxapp/eal/eal_interrupts.c       | 189 ++++++++---
 lib/librte_eal/linuxapp/eal/eal_pci_vfio.c         |  11 +-
 .../linuxapp/eal/include/exec-env/rte_interrupts.h |   4 +
 lib/librte_ether/rte_ethdev.c                      |  45 +++
 lib/librte_ether/rte_ethdev.h                      |  57 ++++
 lib/librte_pmd_ixgbe/ixgbe_ethdev.c                | 356 +++++++++++++++++++++
 lib/librte_pmd_ixgbe/ixgbe_ethdev.h                |   6 +
 9 files changed, 765 insertions(+), 83 deletions(-)

-- 
1.8.1.4