From: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
To: Ilya Maximets <i.maximets@samsung.com>,
"dev@dpdk.org" <dev@dpdk.org>,
"Zhang, Helin" <helin.zhang@intel.com>,
"Wu, Jingjing" <jingjing.wu@intel.com>
Cc: Dyasly Sergey <s.dyasly@samsung.com>,
Heetae Ahn <heetae82.ahn@samsung.com>,
"Richardson, Bruce" <bruce.richardson@intel.com>,
"Yigit, Ferruh" <ferruh.yigit@intel.com>
Subject: Re: [dpdk-dev] [PATCH RFC 1/2] net/i40e: allow bulk alloc for the max size desc ring
Date: Tue, 29 Nov 2016 12:50:22 +0000 [thread overview]
Message-ID: <2601191342CEEE43887BDE71AB9772583F0E19CD@irsmsx105.ger.corp.intel.com> (raw)
In-Reply-To: <0b31fd94-d5b2-acb8-8d55-a6fe124c9886@samsung.com>
Hi Ilya,
> Ping.
>
> Best regards, Ilya Maximets.
>
> On 19.10.2016 17:07, Ilya Maximets wrote:
> > The only reason why bulk alloc disabled for the rings with
> > more than (I40E_MAX_RING_DESC - RTE_PMD_I40E_RX_MAX_BURST)
> > descriptors is the possible out-of-bound access to the dma
> > memory. But it's the artificial limit and can be easily
> > avoided by allocating of RTE_PMD_I40E_RX_MAX_BURST more
> > descriptors in memory. This will not interfere the HW and,
> > as soon as all rings' memory zeroized, Rx functions will
> > work correctly.
> >
> > This change allows to use vectorized Rx functions with
> > 4096 descriptors in Rx ring which is important to achieve
> > zero packet drop rate in high-load installations.
> >
> > Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
> > ---
> > drivers/net/i40e/i40e_rxtx.c | 24 +++++++++++++-----------
> > 1 file changed, 13 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c
> > index 7ae7d9f..1f76691 100644
> > --- a/drivers/net/i40e/i40e_rxtx.c
> > +++ b/drivers/net/i40e/i40e_rxtx.c
> > @@ -409,15 +409,6 @@ check_rx_burst_bulk_alloc_preconditions(__rte_unused struct i40e_rx_queue *rxq)
> > "rxq->rx_free_thresh=%d",
> > rxq->nb_rx_desc, rxq->rx_free_thresh);
> > ret = -EINVAL;
> > - } else if (!(rxq->nb_rx_desc < (I40E_MAX_RING_DESC -
> > - RTE_PMD_I40E_RX_MAX_BURST))) {
> > - PMD_INIT_LOG(DEBUG, "Rx Burst Bulk Alloc Preconditions: "
> > - "rxq->nb_rx_desc=%d, "
> > - "I40E_MAX_RING_DESC=%d, "
> > - "RTE_PMD_I40E_RX_MAX_BURST=%d",
> > - rxq->nb_rx_desc, I40E_MAX_RING_DESC,
> > - RTE_PMD_I40E_RX_MAX_BURST);
> > - ret = -EINVAL;
> > }
> > #else
> > ret = -EINVAL;
> > @@ -1698,8 +1689,19 @@ i40e_dev_rx_queue_setup(struct rte_eth_dev *dev,
> > rxq->rx_deferred_start = rx_conf->rx_deferred_start;
> >
> > /* Allocate the maximun number of RX ring hardware descriptor. */
> > - ring_size = sizeof(union i40e_rx_desc) * I40E_MAX_RING_DESC;
> > - ring_size = RTE_ALIGN(ring_size, I40E_DMA_MEM_ALIGN);
> > + len = I40E_MAX_RING_DESC;
> > +
> > +#ifdef RTE_LIBRTE_I40E_RX_ALLOW_BULK_ALLOC
> > + /**
> > + * Allocating a little more memory because vectorized/bulk_alloc Rx
> > + * functions doesn't check boundaries each time.
> > + */
> > + len += RTE_PMD_I40E_RX_MAX_BURST;
> > +#endif
> > +
Looks good to me.
One question, though do we really need '+#ifdef RTE_LIBRTE_I40E_RX_ALLOW_BULK_ALLOC' here?
Why just not remove this ifdef here and always add allocate extra descriptors.
Konstantin
> > + ring_size = RTE_ALIGN(len * sizeof(union i40e_rx_desc),
> > + I40E_DMA_MEM_ALIGN);
> > +
> > rz = rte_eth_dma_zone_reserve(dev, "rx_ring", queue_idx,
> > ring_size, I40E_RING_BASE_ALIGN, socket_id);
> > if (!rz) {
> >
next prev parent reply other threads:[~2016-11-29 12:54 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20161019140725eucas1p1cb53318d974fb1152f1a7b571f328fd5@eucas1p1.samsung.com>
2016-10-19 14:07 ` [dpdk-dev] [PATCH RFC 0/2] Allow vectorized Rx with 4096 desc ring size on Intel NICs Ilya Maximets
[not found] ` <CGME20161019140730eucas1p2b1cf9daba45bdbf915bb69b24a0a850f@eucas1p2.samsung.com>
2016-10-19 14:07 ` [dpdk-dev] [PATCH RFC 1/2] net/i40e: allow bulk alloc for the max size desc ring Ilya Maximets
2016-11-29 10:59 ` Ilya Maximets
2016-11-29 12:50 ` Ananyev, Konstantin [this message]
2016-11-29 13:06 ` Ilya Maximets
[not found] ` <CGME20161019140735eucas1p267bb4aa03547e70e5f13d78e2ffedcc4@eucas1p2.samsung.com>
2016-10-19 14:07 ` [dpdk-dev] [PATCH RFC 2/2] net/ixgbe: " Ilya Maximets
2016-11-29 10:59 ` Ilya Maximets
2016-10-19 14:30 ` [dpdk-dev] [PATCH RFC 0/2] Allow vectorized Rx with 4096 desc ring size on Intel NICs Ferruh Yigit
2016-11-21 13:53 ` Ferruh Yigit
2016-12-21 12:33 ` Ilya Maximets
2016-12-27 5:03 ` Ilya Maximets
2017-01-02 15:40 ` Thomas Monjalon
2017-01-03 17:24 ` Ferruh Yigit
2017-01-06 2:29 ` Wu, Jingjing
2017-01-06 13:56 ` Ferruh Yigit
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