[dpdk-dev] [PATCH v2 0/5] Interrupt mode for PMD

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

v2 changes
- Fix compilation issue in Makefile for missed header file.
- Consolidate internal and community review comments of v1 patch set.
 
The patch series introduce low-latency one-shot rx interrupt into DPDK with
polling and interrupt mode switch control example.
 
DPDK userspace interrupt notification and 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(PF & VF) and igb PMD(PF only).
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.
 
Known limitations:
1) It does not work for UIO due to a single interrupt eventfd shared by LSC
and rx queue interrupt handlers causes a mess.
2) LSC interrupt is not supported by VF driver, so it is by default disabled
in L3fwd-power now. Feel free to turn in on if you want to support both LSC
and rx queue interrupts on a PF.

Danny Zhou (5):
  ethdev: add rx interrupt enable/disable functions
  ixgbe: enable rx queue interrupts for both PF and VF
  igb: enable rx queue interrupts for PF
  eal: add per rx queue interrupt handling based on VFIO
  l3fwd-power: enable one-shot rx interrupt and polling/interrupt mode
    switch

 examples/l3fwd-power/main.c                        | 141 +++++---
 lib/librte_eal/common/include/rte_eal.h            |  12 +
 lib/librte_eal/linuxapp/eal/Makefile               |   1 +
 lib/librte_eal/linuxapp/eal/eal_interrupts.c       | 181 +++++++---
 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_e1000/e1000/e1000_hw.h              |   3 +
 lib/librte_pmd_e1000/e1000_ethdev.h                |   6 +
 lib/librte_pmd_e1000/igb_ethdev.c                  | 230 +++++++++++--
 lib/librte_pmd_ixgbe/ixgbe_ethdev.c                | 377 ++++++++++++++++++++-
 lib/librte_pmd_ixgbe/ixgbe_ethdev.h                |   9 +
 13 files changed, 965 insertions(+), 112 deletions(-)

-- 
1.8.1.4