Re: [dpdk-dev] [PATCHv2 0/5] ethdev: add new API to retrieve RX/TX queue information

[Bruce Richardson <bruce.richardson@intel.com>]

On Thu, Jun 18, 2015 at 02:56:52PM +0100, Walukiewicz, Miroslaw wrote:
> Yes, really I need a high performance function - it is especially useful on TX path.
> 
> Which queue query function are you talking here to be enhanced?
> 

There are already functions for querying the RX queue - so as to enable power
management/frequency scaling.

rte_eth_rx_queue_count()
rte_eth_rX_descriptor_done()

You could write equivalents for the TX side that only do the minimum needed.
Descriptor-done is probably the simplest and most useful for you, as in you can
query if you have enough space for a single operation, rather than having the
code scan arbitrarily far ahead.

/Bruce

> Mirek
> 
> > -----Original Message-----
> > From: Richardson, Bruce
> > Sent: Thursday, June 18, 2015 3:39 PM
> > To: Walukiewicz, Miroslaw
> > Cc: Ananyev, Konstantin; dev@dpdk.org
> > Subject: Re: [dpdk-dev] [PATCHv2 0/5] ethdev: add new API to retrieve RX/TX
> > queue information
> > 
> > On Thu, Jun 18, 2015 at 01:30:33PM +0000, Walukiewicz, Miroslaw wrote:
> > > Konstantin,
> > >
> > > Is there a possibility to read information about available space in NIC queue
> > for TX.
> > >
> > > It is quite easy to compute (or even available directly)  and very useful
> > especially for application sending multi-descriptor packets like TCP TSO.
> > >
> > > Now there is no access to such information and the transmit packet function
> > must be called to
> > > be sure that there is available space.
> > >
> > > Mirek
> > >
> > 
> > Hi Mirek,
> > 
> > I'm not sure this function is the right place for such a query. It seems that
> > a function like you require needs to be used on the datapath, while this API
> > is not planned to be high-performance. I think that it might be better to
> > add an equivalent function to the existing RX descriptor querying function.
> > 
> > /Bruce
> > 
> > > > -----Original Message-----
> > > > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Konstantin
> > Ananyev
> > > > Sent: Thursday, June 18, 2015 3:19 PM
> > > > To: dev@dpdk.org
> > > > Subject: [dpdk-dev] [PATCHv2 0/5] ethdev: add new API to retrieve RX/TX
> > > > queue information
> > > >
> > > > Add the ability for the upper layer to query RX/TX queue information.
> > > > Right now supported for:
> > > > ixgbe, i40e, e1000 PMDs.
> > > >
> > > > Konstantin Ananyev (5):
> > > >   ethdev: add new API to retrieve RX/TX queue information
> > > >   i40e: add support for eth_(rxq|txq)_info_get
> > > >   ixgbe: add support for eth_(rxq|txq)_info_get
> > > >   e1000: add support for eth_(rxq|txq)_info_get
> > > >   testpmd: add new command to display RX/TX queue information
> > > >
> > > >  app/test-pmd/cmdline.c           | 48 +++++++++++++++++++++++++
> > > >  app/test-pmd/config.c            | 67
> > > > ++++++++++++++++++++++++++++++++++
> > > >  app/test-pmd/testpmd.h           |  2 ++
> > > >  drivers/net/e1000/e1000_ethdev.h | 12 +++++++
> > > >  drivers/net/e1000/em_ethdev.c    |  2 ++
> > > >  drivers/net/e1000/em_rxtx.c      | 38 ++++++++++++++++++++
> > > >  drivers/net/e1000/igb_ethdev.c   |  4 +++
> > > >  drivers/net/e1000/igb_rxtx.c     | 36 +++++++++++++++++++
> > > >  drivers/net/i40e/i40e_ethdev.c   |  2 ++
> > > >  drivers/net/i40e/i40e_ethdev.h   |  5 +++
> > > >  drivers/net/i40e/i40e_rxtx.c     | 42 ++++++++++++++++++++++
> > > >  drivers/net/ixgbe/ixgbe_ethdev.c |  4 +++
> > > >  drivers/net/ixgbe/ixgbe_ethdev.h |  6 ++++
> > > >  drivers/net/ixgbe/ixgbe_rxtx.c   | 42 ++++++++++++++++++++++
> > > >  lib/librte_ether/rte_ethdev.c    | 54 ++++++++++++++++++++++++++++
> > > >  lib/librte_ether/rte_ethdev.h    | 77
> > > > +++++++++++++++++++++++++++++++++++++++-
> > > >  16 files changed, 440 insertions(+), 1 deletion(-)
> > > >
> > > > --
> > > > 1.8.5.3
> > >