> -----Original Message-----
> From: Zhang, Qi Z <qi.z.zh...@intel.com>
> Sent: Monday, May 15, 2023 9:59 AM
> To: Zhang, Qi Z <qi.z.zh...@intel.com>; Feifei Wang
> <feifei.wa...@arm.com>; Richardson, Bruce <bruce.richard...@intel.com>;
> Konstantin Ananyev <konstantin.v.anan...@yandex.ru>; Zhang, Yuying
> <yuying.zh...@intel.com>; Xing, Beilei <beilei.x...@intel.com>; David
> Christensen <d...@linux.vnet.ibm.com>; Ruifeng Wang
> <ruifeng.w...@arm.com>
> Cc: dev@dpdk.org; nd <n...@arm.com>; Honnappa Nagarahalli
> <honnappa.nagaraha...@arm.com>
> Subject: RE: [PATCH v2] net/i40e: remove redundant judgment
>
>
>
> > -----Original Message-----
> > From: Zhang, Qi Z <qi.z.zh...@intel.com>
> > Sent: Thursday, April 27, 2023 3:38 PM
> > To: Feifei Wang <feifei.wa...@arm.com>; Richardson, Bruce
> > <bruce.richard...@intel.com>; Konstantin Ananyev
> > <konstantin.v.anan...@yandex.ru>; Zhang, Yuying
> > <yuying.zh...@intel.com>; Xing, Beilei <beilei.x...@intel.com>; David
> > Christensen <d...@linux.vnet.ibm.com>; Ruifeng Wang
> > <ruifeng.w...@arm.com>
> > Cc: dev@dpdk.org; n...@arm.com; Honnappa Nagarahalli
> > <honnappa.nagaraha...@arm.com>
> > Subject: RE: [PATCH v2] net/i40e: remove redundant judgment
> >
> >
> >
> > > -----Original Message-----
> > > From: Feifei Wang <feifei.wa...@arm.com>
> > > Sent: Tuesday, March 28, 2023 3:28 PM
> > > To: Richardson, Bruce <bruce.richard...@intel.com>; Konstantin
> > > Ananyev <konstantin.v.anan...@yandex.ru>; Zhang, Yuying
> > > <yuying.zh...@intel.com>; Xing, Beilei <beilei.x...@intel.com>;
> > > David Christensen <d...@linux.vnet.ibm.com>; Ruifeng Wang
> > > <ruifeng.w...@arm.com>
> > > Cc: dev@dpdk.org; n...@arm.com; Feifei Wang <feifei.wa...@arm.com>;
> > > Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
> > > Subject: [PATCH v2] net/i40e: remove redundant judgment
> > >
> > > Merged variable updates under the same condition. It reduces branch.
> > >
> > > In ampere-altra, there is no performance improvement with this patch.
> > > In x86 sse and avx2 path, there is also no performance improvement.
> >
> > Thanks for sharing the results. While the code implements some best
> > practices, such as reducing branching and adding compiler hints, which
> > should generally improve performance, it's not necessary to highlight
> > that it didn't provide benefits on certain specific platforms.
> >
> > Would it be ok to remove the last two lines when merging the patch?
>
> Ping
>
Sorry for I did not reply this. I agree with this when merging the patch.
Thanks for the comments~.
> >
> > Otherwise
> > Acked-by: Qi Zhang <qi.z.zh...@intel.com>
> >
> >
> > >
> > >
> > > v2:
> > > 1. add change for avx and altivec path.
> > >
> > > Suggested-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
> > > Signed-off-by: Feifei Wang <feifei.wa...@arm.com>
> > > Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com>
> > > ---
> > > drivers/net/i40e/i40e_rxtx_common_avx.h | 9 +++++----
> > > drivers/net/i40e/i40e_rxtx_vec_altivec.c | 9 +++++----
> > > drivers/net/i40e/i40e_rxtx_vec_neon.c | 9 +++++----
> > > drivers/net/i40e/i40e_rxtx_vec_sse.c | 9 +++++----
> > > 4 files changed, 20 insertions(+), 16 deletions(-)
> > >
> > > diff --git a/drivers/net/i40e/i40e_rxtx_common_avx.h
> > > b/drivers/net/i40e/i40e_rxtx_common_avx.h
> > > index cfc1e63173..85958d6c81 100644
> > > --- a/drivers/net/i40e/i40e_rxtx_common_avx.h
> > > +++ b/drivers/net/i40e/i40e_rxtx_common_avx.h
> > > @@ -198,14 +198,15 @@ i40e_rxq_rearm_common(struct
> i40e_rx_queue
> > *rxq,
> > > __rte_unused bool avx512) #endif
> > >
> > > rxq->rxrearm_start += RTE_I40E_RXQ_REARM_THRESH;
> > > - if (rxq->rxrearm_start >= rxq->nb_rx_desc)
> > > + rx_id = rxq->rxrearm_start - 1;
> > > +
> > > + if (unlikely(rxq->rxrearm_start >= rxq->nb_rx_desc)) {
> > > rxq->rxrearm_start = 0;
> > > + rx_id = rxq->nb_rx_desc - 1;
> > > + }
> > >
> > > rxq->rxrearm_nb -= RTE_I40E_RXQ_REARM_THRESH;
> > >
> > > - rx_id = (uint16_t)((rxq->rxrearm_start == 0) ?
> > > - (rxq->nb_rx_desc - 1) : (rxq->rxrearm_start - 1));
> > > -
> > > /* Update the tail pointer on the NIC */
> > > I40E_PCI_REG_WC_WRITE(rxq->qrx_tail, rx_id); } diff --git
> > > a/drivers/net/i40e/i40e_rxtx_vec_altivec.c
> > > b/drivers/net/i40e/i40e_rxtx_vec_altivec.c
> > > index 2dfa04599c..8672ad1c41 100644
> > > --- a/drivers/net/i40e/i40e_rxtx_vec_altivec.c
> > > +++ b/drivers/net/i40e/i40e_rxtx_vec_altivec.c
> > > @@ -89,14 +89,15 @@ i40e_rxq_rearm(struct i40e_rx_queue *rxq)
> > > }
> > >
> > > rxq->rxrearm_start += RTE_I40E_RXQ_REARM_THRESH;
> > > - if (rxq->rxrearm_start >= rxq->nb_rx_desc)
> > > + rx_id = rxq->rxrearm_start - 1;
> > > +
> > > + if (unlikely(rxq->rxrearm_start >= rxq->nb_rx_desc)) {
> > > rxq->rxrearm_start = 0;
> > > + rx_id = rxq->nb_rx_desc - 1;
> > > + }
> > >
> > > rxq->rxrearm_nb -= RTE_I40E_RXQ_REARM_THRESH;
> > >
> > > - rx_id = (uint16_t)((rxq->rxrearm_start == 0) ?
> > > - (rxq->nb_rx_desc - 1) : (rxq->rxrearm_start - 1));
> > > -
> > > /* Update the tail pointer on the NIC */
> > > I40E_PCI_REG_WRITE(rxq->qrx_tail, rx_id); } diff --git
> > > a/drivers/net/i40e/i40e_rxtx_vec_neon.c
> > > b/drivers/net/i40e/i40e_rxtx_vec_neon.c
> > > index 12e6f1cbcb..49391fe4c7 100644
> > > --- a/drivers/net/i40e/i40e_rxtx_vec_neon.c
> > > +++ b/drivers/net/i40e/i40e_rxtx_vec_neon.c
> > > @@ -64,14 +64,15 @@ i40e_rxq_rearm(struct i40e_rx_queue *rxq)
> > > }
> > >
> > > rxq->rxrearm_start += RTE_I40E_RXQ_REARM_THRESH;
> > > - if (rxq->rxrearm_start >= rxq->nb_rx_desc)
> > > + rx_id = rxq->rxrearm_start - 1;
> > > +
> > > + if (unlikely(rxq->rxrearm_start >= rxq->nb_rx_desc)) {
> > > rxq->rxrearm_start = 0;
> > > + rx_id = rxq->nb_rx_desc - 1;
> > > + }
> > >
> > > rxq->rxrearm_nb -= RTE_I40E_RXQ_REARM_THRESH;
> > >
> > > - rx_id = (uint16_t)((rxq->rxrearm_start == 0) ?
> > > - (rxq->nb_rx_desc - 1) : (rxq->rxrearm_start - 1));
> > > -
> > > rte_io_wmb();
> > > /* Update the tail pointer on the NIC */
> > > I40E_PCI_REG_WRITE_RELAXED(rxq->qrx_tail, rx_id); diff --git
> > > a/drivers/net/i40e/i40e_rxtx_vec_sse.c
> > > b/drivers/net/i40e/i40e_rxtx_vec_sse.c
> > > index bdc979a839..baf83cb3df 100644
> > > --- a/drivers/net/i40e/i40e_rxtx_vec_sse.c
> > > +++ b/drivers/net/i40e/i40e_rxtx_vec_sse.c
> > > @@ -77,14 +77,15 @@ i40e_rxq_rearm(struct i40e_rx_queue *rxq)
> > > }
> > >
> > > rxq->rxrearm_start += RTE_I40E_RXQ_REARM_THRESH;
> > > - if (rxq->rxrearm_start >= rxq->nb_rx_desc)
> > > + rx_id = rxq->rxrearm_start - 1;
> > > +
> > > + if (unlikely(rxq->rxrearm_start >= rxq->nb_rx_desc)) {
> > > rxq->rxrearm_start = 0;
> > > + rx_id = rxq->nb_rx_desc - 1;
> > > + }
> > >
> > > rxq->rxrearm_nb -= RTE_I40E_RXQ_REARM_THRESH;
> > >
> > > - rx_id = (uint16_t)((rxq->rxrearm_start == 0) ?
> > > - (rxq->nb_rx_desc - 1) : (rxq->rxrearm_start - 1));
> > > -
> > > /* Update the tail pointer on the NIC */
> > > I40E_PCI_REG_WC_WRITE(rxq->qrx_tail, rx_id); }
> > > --
> > > 2.25.1
