On Wed, Jul 22, 2015 at 10:47:34AM +0100, Zoltan Kiss wrote:
> Hi,
>
> And what happens if someone changes RTE_IXGBE_VPMD_RX_BURST to something
> else than 32? I guess this bug were introduced when someone raised it from
> 16 to 32
Actually, no, this bug is purely due to me getting my maths wrong when I
wrote this function. The vector PMD has always worked in bursts of 32 at a
time.
> I think you are better off with a for loop which uses this value. Or at
> least make a comment around RTE_IXGBE_VPMD_RX_BURST that if you change that
> value this check should be modified as well.
The vector PMD always works off a fixed 32 burst size. Any change to that will
lead to many changes in the code, so I don't believe a loop is necessary.
Regards,
/Bruce
>
> Regards,
>
> Zoltan
>
> On 22/07/15 10:13, Bruce Richardson wrote:
> >The check for split packets to be reassembled in the vector ixgbe PMD
> >was incorrectly only checking the first 16 elements of the array instead
> >of all 32. This is fixed by changing the uint32_t values to be uint64_t
> >instead.
> >
> >Fixes: cf4b4708a88a ("ixgbe: improve slow-path perf with vector scattered
> >Rx")
> >
> >Reported-by: Zoltan Kiss <zoltan.kiss at linaro.org>
> >Signed-off-by: Bruce Richardson <bruce.richardson at intel.com>
> >
> >---
> >V2: Rename variable from split_fl32 to split_fl64 to match type change.
> >---
> > drivers/net/ixgbe/ixgbe_rxtx_vec.c | 6 +++---
> > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> >diff --git a/drivers/net/ixgbe/ixgbe_rxtx_vec.c
> >b/drivers/net/ixgbe/ixgbe_rxtx_vec.c
> >index d3ac74a..f2052c6 100644
> >--- a/drivers/net/ixgbe/ixgbe_rxtx_vec.c
> >+++ b/drivers/net/ixgbe/ixgbe_rxtx_vec.c
> >@@ -549,10 +549,10 @@ ixgbe_recv_scattered_pkts_vec(void *rx_queue, struct
> >rte_mbuf **rx_pkts,
> > return 0;
> >
> > /* happy day case, full burst + no packets to be joined */
> >- const uint32_t *split_fl32 = (uint32_t *)split_flags;
> >+ const uint64_t *split_fl64 = (uint64_t *)split_flags;
> > if (rxq->pkt_first_seg == NULL &&
> >- split_fl32[0] == 0 && split_fl32[1] == 0 &&
> >- split_fl32[2] == 0 && split_fl32[3] == 0)
> >+ split_fl64[0] == 0 && split_fl64[1] == 0 &&
> >+ split_fl64[2] == 0 && split_fl64[3] == 0)
> > return nb_bufs;
> >
> > /* reassemble any packets that need reassembly*/
> >
