Re: [dpdk-dev] [BUG] ixgbe vector cannot compile without bulk alloc

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

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Bruce Richardson
> Sent: Thursday, January 29, 2015 4:28 PM
> To: Thomas Monjalon
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [BUG] ixgbe vector cannot compile without bulk alloc
> 
> On Thu, Jan 29, 2015 at 11:18:01PM +0100, Thomas Monjalon wrote:
> > 2014-12-01 18:22, Thomas Monjalon:
> > > 2014-12-01 17:18, Bruce Richardson:
> > > > On Mon, Dec 01, 2014 at 06:10:18PM +0100, Thomas Monjalon wrote:
> > > > > These 2 configuration options are incompatible:
> > > > > 	CONFIG_RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC=n
> > > > > 	CONFIG_RTE_IXGBE_INC_VECTOR=y
> > > > > Building this config gives this error:
> > > > > 	lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c:69:24:
> > > > > 	error: ‘struct igb_rx_queue’ has no member named ‘fake_mbuf’
> > > > >
> > > > > I'd like a confirmation that it will be always incompatible.
> > > > > Thanks
> > > >
> > > > Hi Thomas,
> > > >
> > > > I don't think these options should always be incompatible, though as you
> point
> > > > out you do need to turn on bulk alloc support in order to use the vector
> PMD.
> > > > Why do you ask? There are no immediate plans to remove the dependency
> on our end.
> >
> > So you confirm that the ixgbe vpmd really needs Rx bulk alloc and this kind of
> > patch cannot work at all (I don't know the design of vpmd):
> >
> > --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> > +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> > @@ -2119,12 +2119,12 @@ ixgbe_reset_rx_queue(struct igb_rx_queue *rxq)
> >                 rxq->rx_ring[i] = zeroed_desc;
> >         }
> >
> > -#ifdef RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC
> >         /*
> >          * initialize extra software ring entries. Space for these extra
> >          * entries is always allocated
> >          */
> >         memset(&rxq->fake_mbuf, 0x0, sizeof(rxq->fake_mbuf));
> > +#ifdef RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC
> >         for (i = 0; i < RTE_PMD_IXGBE_RX_MAX_BURST; ++i) {
> >                 rxq->sw_ring[rxq->nb_rx_desc + i].mbuf =
> &rxq->fake_mbuf;
> >         }
> > --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.h
> > +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.h
> > @@ -127,9 +127,9 @@ struct igb_rx_queue {
> >         uint8_t             crc_len;  /**< 0 if CRC stripped, 4 otherwise.
> */
> >         uint8_t             drop_en;  /**< If not 0, set SRRCTL.Drop_En.
> */
> >         uint8_t             rx_deferred_start; /**< not in global dev start.
> */
> > -#ifdef RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC
> >         /** need to alloc dummy mbuf, for wraparound when scanning hw
> ring */
> >         struct rte_mbuf fake_mbuf;
> > +#ifdef RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC
> >         /** hold packets to return to application */
> >         struct rte_mbuf *rx_stage[RTE_PMD_IXGBE_RX_MAX_BURST*2];
> >  #endif
> >
> > > I think the compilation shouldn't fail without a proper message.
> > > In order to distinguish a real compilation error from an incompatibility,
> > > we should add a warning in the makefile.
> > > Ideally, the build system should handle dependencies. But waiting this ideal
> > > time, a warning would be graceful.
> >
> > Do you agree that something like this would be OK?
> >
> > --- a/lib/librte_pmd_ixgbe/Makefile
> > +++ b/lib/librte_pmd_ixgbe/Makefile
> > @@ -114,4 +114,8 @@ DEPDIRS-$(CONFIG_RTE_LIBRTE_IXGBE_PMD) +=
> lib/librte_eal lib/librte_ether
> >  DEPDIRS-$(CONFIG_RTE_LIBRTE_IXGBE_PMD) += lib/librte_mempool
> lib/librte_mbuf
> >  DEPDIRS-$(CONFIG_RTE_LIBRTE_IXGBE_PMD) += lib/librte_net
> lib/librte_malloc
> >
> > +ifeq
> ($(CONFIG_RTE_IXGBE_INC_VECTOR)$(CONFIG_RTE_LIBRTE_IXGBE_RX_ALLOW_B
> ULK_ALLOC),yn)
> > +$(error The ixgbe vpmd depends on Rx bulk alloc)
> > +endif
> > +
> >  include $(RTE_SDK)/mk/rte.lib.mk
> >
> 
> Something like the above looks like a good solution to me.
> 
> /Bruce
[Liang, Cunming] To avoid compile complain, this one is ok.
It's doable to remove the dependence between two.
We can submit it in a separate patch.
> 
> > Thanks
> > --
> > Thomas