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

[Thomas Monjalon <thomas.monjalon@6wind.com>]

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_BULK_ALLOC),yn)
+$(error The ixgbe vpmd depends on Rx bulk alloc)
+endif
+
 include $(RTE_SDK)/mk/rte.lib.mk

Thanks
-- 
Thomas