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From: Bruce Richardson <bruce.richardson@intel.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH RFC 0/3] DPDK ethdev callback support
Date: Tue, 23 Dec 2014 09:29:09 +0000	[thread overview]
Message-ID: <20141223092909.GC10244@bricha3-MOBL3> (raw)
In-Reply-To: <20141222103157.58e33123@urahara>

On Mon, Dec 22, 2014 at 10:31:57AM -0800, Stephen Hemminger wrote:
> On Mon, 22 Dec 2014 16:47:21 +0000
> Bruce Richardson <bruce.richardson@intel.com> wrote:
> 
> > This RFC 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.
> > 
> > Use case: the first use case for this is to enable a consistent set of 
> > packets mbufs to be received by applications irrespective of the NIC used
> > to receive those. For example, for a port type that does not support RSS,
> > a callback on RX can be configured to calculate a hash in software. 
> > Similarly, this mechanism can be used to add other information to mbufs
> > as they are received, such as timestamps or sequence numbers, without cluttering
> > up the main packet processing path with checks for whether packets have these
> > fields filled in or not.
> > A second use case is ease of intrumenting existing code. The example application 
> > shows how combining a timestamp insertion callback on RX can be paired with a 
> > latency calculation callback on TX to easily instrument any application for
> > packet latency.
> > A third use case is to potentially extend existing NIC capabilities beyond
> > what is currently supported. For example, where flow director capabilities
> > can match up to a certain limit of flows - in the thousands, in the case of
> > NICs using the ixgbe driver - a callback can extend this to potentially
> > millions of flows by using a software hash table lookup inline for packets
> > that missing the hardware lookup filters. It would all appear transparent 
> > to the packet handling code in the main application.
> > 
> > Future extensions: in future the ethdev library can be extended to provide
> > a standard set of callbacks for use by drivers. 
> > 
> > For now this patch set is RFC and still needs additional work for creating
> > a remove function for callbacks and to add in additional testing code.
> > Since this adds in new code into the critical data path, I have run some
> > performance tests using testpmd with the ixgbe vector drivers (i.e. the
> > fastest, fast-path we have :-) ). Performance drops due to this patch
> > seems minimal to non-existant, rough tests on my system indicate a drop
> > of perhaps 1%.
> > 
> > All feedback welcome.
> > 
> > Bruce Richardson (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          | 103 +++++++++++++--
> >  lib/librte_ether/rte_ethdev.h          | 125 ++++++++++++++++++-
> >  lib/librte_pmd_bond/rte_eth_bond_api.c |   2 +-
> >  7 files changed, 543 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
> > 
> 
> What about SMP safety? The callback list is not thread safe.
> Do you plan to start integrating with an RCU framework like userspace RCU?

I hadn't considered multiple CPUs adding removing callbacks simultaneously. I'll
look into it.

/Bruce

  reply	other threads:[~2014-12-23  9:29 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-22 16:47 Bruce Richardson
2014-12-22 16:47 ` [dpdk-dev] [PATCH RFC 1/3] ethdev: rename callbacks field to intr_cbs Bruce Richardson
2014-12-22 16:47 ` [dpdk-dev] [PATCH RFC 2/3] ethdev: Add in data rxtx callback support Bruce Richardson
2014-12-22 16:47 ` [dpdk-dev] [PATCH RFC 3/3] examples: example showing use of callbacks Bruce Richardson
2014-12-22 17:02 ` [dpdk-dev] [PATCH RFC 0/3] DPDK ethdev callback support Thomas Monjalon
2014-12-22 17:33   ` Bruce Richardson
2014-12-22 17:47     ` Neil Horman
2014-12-23  9:28       ` Bruce Richardson
2014-12-23 13:09         ` Neil Horman
2014-12-23 14:09           ` Bruce Richardson
2015-01-05 16:17     ` Bruce Richardson
2014-12-22 18:31 ` Stephen Hemminger
2014-12-23  9:29   ` Bruce Richardson [this message]
2014-12-23  4:23 ` Vithal S Mohare
2014-12-23  9:30   ` Bruce Richardson
2014-12-23  9:37     ` Vithal S Mohare
2014-12-24  1:43       ` Zhang, Helin
2014-12-24  5:06 ` Qiu, Michael
2015-02-12 19:57 ` [dpdk-dev] [PATCH " John McNamara
2015-02-12 19:57   ` [dpdk-dev] [PATCH 1/3] ethdev: rename callbacks field to intr_cbs John McNamara
2015-02-12 19:57   ` [dpdk-dev] [PATCH 2/3] ethdev: Add in data rxtx callback support John McNamara
2015-02-12 21:12     ` Neil Horman
2015-02-12 19:57   ` [dpdk-dev] [PATCH 3/3] examples: example showing use of callbacks John McNamara
2015-02-13 14:54   ` [dpdk-dev] [PATCH 0/3] DPDK ethdev callback support Declan Doherty
2015-02-13 15:39 ` [dpdk-dev] [PATCH v2 0/4] " John McNamara
2015-02-13 15:39   ` [dpdk-dev] [PATCH v2 1/4] ethdev: rename callbacks field to intr_cbs John McNamara
2015-02-13 16:06     ` Thomas Monjalon
2015-02-13 16:52       ` Thomas Monjalon
2015-02-13 15:39   ` [dpdk-dev] [PATCH v2 2/4] ethdev: Add in data rxtx callback support John McNamara
2015-02-13 16:33     ` Thomas Monjalon
2015-02-13 17:49       ` Bruce Richardson
2015-02-13 15:39   ` [dpdk-dev] [PATCH v2 3/4] examples: example showing use of callbacks John McNamara
2015-02-13 16:02     ` Thomas Monjalon
2015-02-16 14:33     ` Olivier MATZ
2015-02-16 15:16       ` Bruce Richardson
2015-02-16 17:34         ` Thomas Monjalon
2015-02-17 12:17           ` Declan Doherty
2015-02-17 12:25           ` Bruce Richardson
2015-02-17 13:28             ` Olivier MATZ
2015-02-17 13:50               ` Bruce Richardson
2015-02-17 15:49                 ` Neil Horman
2015-02-17 16:00                   ` Bruce Richardson
2015-02-17 16:08                     ` Neil Horman
2015-02-17 16:15                       ` Bruce Richardson
2015-02-17 19:27                         ` Neil Horman
2015-02-17 15:32             ` Thomas Monjalon
2015-02-17 15:58               ` Bruce Richardson
2015-02-13 15:39   ` [dpdk-dev] [PATCH v2 4/4] abi: Added rxtx callback functions to ABI versioning John McNamara
2015-02-13 15:59     ` Thomas Monjalon
2015-02-13 15:48   ` [dpdk-dev] [PATCH v2 0/4] DPDK ethdev callback support Declan Doherty
2015-02-18 17:42 ` [dpdk-dev] [PATCH v3 0/3] " John McNamara
2015-02-18 17:42   ` [dpdk-dev] [PATCH v3 1/3] ethdev: Rename callbacks field to link_intr_cbs John McNamara
2015-02-18 17:42   ` [dpdk-dev] [PATCH v3 2/3] ethdev: Add rxtx callback support John McNamara
2015-02-18 18:19     ` Thomas Monjalon
2015-02-19  9:33       ` Mcnamara, John
2015-02-18 17:42   ` [dpdk-dev] [PATCH v3 3/3] examples: example showing use of callbacks John McNamara
2015-02-19 17:56   ` [dpdk-dev] [PATCH v4 0/3] DPDK ethdev callback support John McNamara
2015-02-19 17:56     ` [dpdk-dev] [PATCH v4 1/3] ethdev: rename callbacks field to link_intr_cbs John McNamara
2015-02-19 17:56     ` [dpdk-dev] [PATCH v4 2/3] ethdev: add optional rxtx callback support John McNamara
2015-02-20 10:06       ` Bruce Richardson
2015-02-20 10:31         ` Thomas Monjalon
2015-02-19 17:56     ` [dpdk-dev] [PATCH v4 3/3] examples: example showing use of callbacks John McNamara
2015-02-20 17:03   ` [dpdk-dev] [PATCH v5 0/3] DPDK ethdev callback support John McNamara
2015-02-20 17:03     ` [dpdk-dev] [PATCH v5 1/3] ethdev: rename callbacks field to link_intr_cbs John McNamara
2015-02-20 17:03     ` [dpdk-dev] [PATCH v5 2/3] ethdev: add optional rxtx callback support John McNamara
2015-02-23 15:11       ` Thomas Monjalon
2015-02-23 17:27         ` Mcnamara, John
2015-02-20 17:03     ` [dpdk-dev] [PATCH v5 3/3] examples: example showing use of callbacks John McNamara
2015-02-23 18:30   ` [dpdk-dev] [PATCH v6 0/3] DPDK ethdev callback support John McNamara
2015-02-23 18:30     ` [dpdk-dev] [PATCH v6 1/3] ethdev: rename callbacks field to link_intr_cbs John McNamara
2015-02-23 18:30     ` [dpdk-dev] [PATCH v6 2/3] ethdev: add optional rxtx callback support John McNamara
2015-02-23 18:30     ` [dpdk-dev] [PATCH v6 3/3] examples: example showing use of callbacks John McNamara
2015-02-23 23:39     ` [dpdk-dev] [PATCH v6 0/3] DPDK ethdev callback support Thomas Monjalon

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