From: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
To: Jianbo Liu <jianbo.liu@linaro.org>, "dev@dpdk.org" <dev@dpdk.org>,
"Zhang, Helin" <helin.zhang@intel.com>,
"jerin.jacob@caviumnetworks.com" <jerin.jacob@caviumnetworks.com>
Subject: Re: [dpdk-dev] [PATCH 1/2] net/ixgbe: calculate the correct number of received packets in bulk alloc function
Date: Wed, 1 Feb 2017 16:19:33 +0000 [thread overview]
Message-ID: <2601191342CEEE43887BDE71AB9772583F10FF87@irsmsx105.ger.corp.intel.com> (raw)
In-Reply-To: <1482127758-4904-1-git-send-email-jianbo.liu@linaro.org>
Hi,
> -----Original Message-----
> From: Jianbo Liu [mailto:jianbo.liu@linaro.org]
> Sent: Monday, December 19, 2016 6:09 AM
> To: dev@dpdk.org; Zhang, Helin <helin.zhang@intel.com>; Ananyev, Konstantin <konstantin.ananyev@intel.com>;
> jerin.jacob@caviumnetworks.com
> Cc: Jianbo Liu <jianbo.liu@linaro.org>
> Subject: [PATCH 1/2] net/ixgbe: calculate the correct number of received packets in bulk alloc function
>
> To get better performance, Rx bulk alloc recv function will scan 8 descriptors
> in one time, but the statuses are not consistent on ARM platform because
> the memory allocated for Rx descriptors is cacheable hugepages.
> This patch is to calculate the number of received packets by scanning DD bit
> sequentially, and stops when meeting the first packet with DD bit unset.
>
> Signed-off-by: Jianbo Liu <jianbo.liu@linaro.org>
> ---
> drivers/net/ixgbe/ixgbe_rxtx.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
> index b2d9f45..2866bdb 100644
> --- a/drivers/net/ixgbe/ixgbe_rxtx.c
> +++ b/drivers/net/ixgbe/ixgbe_rxtx.c
> @@ -1402,17 +1402,21 @@ ixgbe_rx_scan_hw_ring(struct ixgbe_rx_queue *rxq)
> for (i = 0; i < RTE_PMD_IXGBE_RX_MAX_BURST;
> i += LOOK_AHEAD, rxdp += LOOK_AHEAD, rxep += LOOK_AHEAD) {
> /* Read desc statuses backwards to avoid race condition */
> - for (j = LOOK_AHEAD-1; j >= 0; --j)
> + for (j = LOOK_AHEAD - 1; j >= 0; --j) {
> s[j] = rte_le_to_cpu_32(rxdp[j].wb.upper.status_error);
> -
> - for (j = LOOK_AHEAD - 1; j >= 0; --j)
> pkt_info[j] = rte_le_to_cpu_32(rxdp[j].wb.lower.
> lo_dword.data);
> + }
> +
> + rte_smp_rmb();
If reads can be reordered, shouldn't we fill pkt_info[] after smp_rmb() here?
As another nit - with rmb() in and because you are looking the first gap in s[] now,
no need to read TXDs in backward order.
How it looks to me (as a suggestion):
for (j = 0; j != LOOK_AHEAD; j++)
s[j] = rte_le_to_cpu_32(rxdp[j].wb.upper.status_error);
rte_smp_rmb();
for (j = 0; j < LOOK_AHEAD && (s[j] & IXGBE_RXDADV_STAT_DD) != 0; j++)
;
for (j = 0; j < nb_dd; ++j) {
pkt_info[j] = rte_le_to_cpu_32(rxdp[j].wb.lower.lo_dword.data);
....
Konstantin
>
> /* Compute how many status bits were set */
> nb_dd = 0;
> for (j = 0; j < LOOK_AHEAD; ++j)
> - nb_dd += s[j] & IXGBE_RXDADV_STAT_DD;
> + if (s[j] & IXGBE_RXDADV_STAT_DD)
> + ++nb_dd;
> + else
> + break;
>
> nb_rx += nb_dd;
>
> --
> 2.4.11
next prev parent reply other threads:[~2017-02-01 16:19 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-19 6:09 Jianbo Liu
2016-12-19 6:09 ` [dpdk-dev] [PATCH 2/2] net/ixgbe: calculate correct number of received packets for ARM NEON-version vPMD Jianbo Liu
2016-12-21 10:08 ` Jerin Jacob
2016-12-21 11:03 ` Bruce Richardson
2016-12-22 1:18 ` Jianbo Liu
2016-12-22 1:05 ` Jianbo Liu
2017-02-01 16:19 ` Ananyev, Konstantin [this message]
2017-02-03 6:22 ` [dpdk-dev] [PATCH 1/2] net/ixgbe: calculate the correct number of received packets in bulk alloc function Jianbo Liu
2017-02-03 11:38 ` Ananyev, Konstantin
2017-02-04 3:37 ` Jianbo Liu
2017-02-04 9:37 ` [dpdk-dev] [PATCH v2 " Jianbo Liu
2017-02-04 9:37 ` [dpdk-dev] [PATCH v2 2/2] net/ixgbe: calculate correct number of received packets for ARM NEON-version vPMD Jianbo Liu
2017-02-04 13:26 ` [dpdk-dev] [PATCH v2 1/2] net/ixgbe: calculate the correct number of received packets in bulk alloc function Ananyev, Konstantin
2017-02-08 18:02 ` Ferruh Yigit
2017-02-08 18:53 ` Ananyev, Konstantin
2017-02-08 19:53 ` Ananyev, Konstantin
2017-02-09 3:49 ` Jianbo Liu
2017-02-04 16:37 ` [dpdk-dev] [PATCH v3 " Jianbo Liu
2017-02-04 16:37 ` [dpdk-dev] [PATCH v3 2/2] net/ixgbe: calculate correct number of received packets for ARM NEON-version vPMD Jianbo Liu
2017-02-04 16:39 ` [dpdk-dev] [PATCH v3 1/2] net/ixgbe: calculate the correct number of received packets in bulk alloc function Jianbo Liu
2017-02-09 4:05 ` [dpdk-dev] [PATCH v4 " Jianbo Liu
2017-02-09 4:05 ` [dpdk-dev] [PATCH v4 2/2] net/ixgbe: calculate correct number of received packets for ARM NEON-version vPMD Jianbo Liu
2017-02-09 12:43 ` Ferruh Yigit
2017-02-09 12:39 ` [dpdk-dev] [PATCH v4 1/2] net/ixgbe: calculate the correct number of received packets in bulk alloc function Ferruh Yigit
2017-02-09 12:42 ` Ferruh Yigit
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