[dpdk-dev] [PATCH 0/3] DPDK ethdev callback support
Declan Doherty
declan.doherty at intel.com
Fri Feb 13 15:54:39 CET 2015
On 12/02/15 19:57, John McNamara wrote:
> This patchset is for a small addition to the ethdev library, to
> add in support for callbacks at the RX and TX stages. This allows
> packet processing to be done on packets before they get returned
> to applications using rte_eth_rx_burst call.
>
> See the RFC cover letter for the use cases:
>
> http://dpdk.org/ml/archives/dev/2014-December/010491.html
>
> For this version we spent some time investigating Stephen Hemminger's
> suggestion of using the userspace RCU (read-copy-update) library for
> SMP safety:
>
> http://urcu.so/
>
> The default liburcu (which defaulted to liburcu-mb) requires the least
> interaction from the end user but showed a 25% drop in packet throughput
> in the callback sample app.
>
> The liburcu-qsbr (quiescent state) variant showed a 1% drop in packet
> throughput in the callback sample app. However it requires registered
> RCU threads in the program to periodically announce quiescent states.
> This makes it more difficult to implement for end user applications.
>
> For this release we will document that callbacks should be added/removed
> on stopped ports.
>
> Version 1 changes:
> * Added callback removal functions.
> * Minor fixes.
>
>
> Richardson, Bruce (3):
> ethdev: rename callbacks field to intr_cbs
> ethdev: Add in data rxtx callback support
> examples: example showing use of callbacks.
>
> app/test/virtual_pmd.c | 2 +-
> examples/rxtx_callbacks/Makefile | 57 ++++++++
> examples/rxtx_callbacks/basicfwd.c | 222 ++++++++++++++++++++++++++++++++
> examples/rxtx_callbacks/basicfwd.h | 46 +++++++
> lib/librte_ether/rte_ethdev.c | 177 ++++++++++++++++++++++++--
> lib/librte_ether/rte_ethdev.h | 175 +++++++++++++++++++++++++-
> lib/librte_pmd_bond/rte_eth_bond_api.c | 2 +-
> 7 files changed, 667 insertions(+), 14 deletions(-)
> create mode 100644 examples/rxtx_callbacks/Makefile
> create mode 100644 examples/rxtx_callbacks/basicfwd.c
> create mode 100644 examples/rxtx_callbacks/basicfwd.h
>
Looks good to me, I'll ack the next version which has addressed the ABI
issues Neil raised. Also, it should probably be noted in the doxygen
comments for the add/remove rxtx callbacks that as currently implemented
the addition/removal of callbacks isn't thread safe
Declan
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