Re: [dpdk-dev] [PATCH v3 0/5] Interrupt mode PMD

["Liang, Cunming" <cunming.liang@intel.com>]

Hi,

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Zhou Danny
> Sent: Tuesday, February 17, 2015 9:47 PM
> To: dev@dpdk.org
> Subject: [dpdk-dev] [PATCH v3 0/5] Interrupt mode PMD
> 
> v3 changes
> - Add return value for interrupt enable/disable functions
> - Move spinlok from PMD to L3fwd-power
> - Remove unnecessary variables in e1000_mac_info
> - Fix miscelleous review comments
> 
> 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                        | 153 ++++++---
>  lib/librte_eal/common/include/rte_eal.h            |  12 +
>  lib/librte_eal/linuxapp/eal/Makefile               |   1 +
>  lib/librte_eal/linuxapp/eal/eal_interrupts.c       | 190 ++++++++---
>  lib/librte_eal/linuxapp/eal/eal_pci_vfio.c         |  12 +-
>  .../linuxapp/eal/include/exec-env/rte_interrupts.h |   4 +
>  lib/librte_ether/rte_ethdev.c                      |  43 +++
>  lib/librte_ether/rte_ethdev.h                      |  57 ++++
>  lib/librte_pmd_e1000/e1000_ethdev.h                |   3 +
>  lib/librte_pmd_e1000/igb_ethdev.c                  | 228 +++++++++++--
>  lib/librte_pmd_ixgbe/ixgbe_ethdev.c                | 365
> ++++++++++++++++++++-
>  lib/librte_pmd_ixgbe/ixgbe_ethdev.h                |   6 +
>  13 files changed, 963 insertions(+), 114 deletions(-)
> 
> --
> 1.8.1.4

Acked-by:  Cunming Liang <cunming.liang@intel.com>