From 78c7a16daad1b3948b84399203cf225aa153a45c Mon Sep 17 00:00:00 2001 From: Yongseok Koh Date: Tue, 15 Jan 2019 09:38:58 -0800 Subject: [PATCH] net/mlx5: fix Rx packet padding Rx packet padding is supposed to be set by an environment variable - MLX5_PMD_ENABLE_PADDING, but it has been missing for some time by mistake. Rather than using such a variable, a PMD parameter (rxq_pkt_pad_en) is added instead. Fixes: a1366b1a2be3 ("net/mlx5: add reference counter on DPDK Rx queues") Cc: stable@dpdk.org Signed-off-by: Yongseok Koh Reviewed-by: Erez Ferber Acked-by: Shahaf Shuler --- doc/guides/nics/mlx5.rst | 27 +++++++++++++-------------- drivers/net/mlx5/mlx5.c | 18 +++++++++++++++--- 2 files changed, 28 insertions(+), 17 deletions(-) diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst index 5ddca44eed..3f168b1613 100644 --- a/doc/guides/nics/mlx5.rst +++ b/doc/guides/nics/mlx5.rst @@ -233,20 +233,6 @@ Environment variables enabled and most useful when ``CONFIG_RTE_EAL_PMD_PATH`` is also set, since ``LD_LIBRARY_PATH`` has no effect in this case. -- ``MLX5_PMD_ENABLE_PADDING`` - - Enables HW packet padding in PCI bus transactions. - - When packet size is cache aligned and CRC stripping is enabled, 4 fewer - bytes are written to the PCI bus. Enabling padding makes such packets - aligned again. - - In cases where PCI bandwidth is the bottleneck, padding can improve - performance by 10%. - - This is disabled by default since this can also decrease performance for - unaligned packet sizes. - - ``MLX5_SHUT_UP_BF`` Configures HW Tx doorbell register as IO-mapped. @@ -301,6 +287,19 @@ Run-time configuration - CPU having 128B cacheline with ConnectX-5 and Bluefield. +- ``rxq_pkt_pad_en`` parameter [int] + + A nonzero value enables padding Rx packet to the size of cacheline on PCI + transaction. This feature would waste PCI bandwidth but could improve + performance by avoiding partial cacheline write which may cause costly + read-modify-copy in memory transaction on some architectures. Disabled by + default. + + Supported on: + + - x86_64 with ConnectX-4, ConnectX-4 LX, ConnectX-5, ConnectX-6 and Bluefield. + - POWER8 and ARMv8 with ConnectX-4 LX, ConnectX-5, ConnectX-6 and Bluefield. + - ``mprq_en`` parameter [int] A nonzero value enables configuring Multi-Packet Rx queues. Rx queue is diff --git a/drivers/net/mlx5/mlx5.c b/drivers/net/mlx5/mlx5.c index a84e1afa09..741bc7fc07 100644 --- a/drivers/net/mlx5/mlx5.c +++ b/drivers/net/mlx5/mlx5.c @@ -54,6 +54,9 @@ /* Device parameter to enable RX completion entry padding to 128B. */ #define MLX5_RXQ_CQE_PAD_EN "rxq_cqe_pad_en" +/* Device parameter to enable padding Rx packet to cacheline size. */ +#define MLX5_RXQ_PKT_PAD_EN "rxq_pkt_pad_en" + /* Device parameter to enable Multi-Packet Rx queue. */ #define MLX5_RX_MPRQ_EN "mprq_en" @@ -486,6 +489,8 @@ mlx5_args_check(const char *key, const char *val, void *opaque) config->cqe_comp = !!tmp; } else if (strcmp(MLX5_RXQ_CQE_PAD_EN, key) == 0) { config->cqe_pad = !!tmp; + } else if (strcmp(MLX5_RXQ_PKT_PAD_EN, key) == 0) { + config->hw_padding = !!tmp; } else if (strcmp(MLX5_RX_MPRQ_EN, key) == 0) { config->mprq.enabled = !!tmp; } else if (strcmp(MLX5_RX_MPRQ_LOG_STRIDE_NUM, key) == 0) { @@ -541,6 +546,7 @@ mlx5_args(struct mlx5_dev_config *config, struct rte_devargs *devargs) const char **params = (const char *[]){ MLX5_RXQ_CQE_COMP_EN, MLX5_RXQ_CQE_PAD_EN, + MLX5_RXQ_PKT_PAD_EN, MLX5_RX_MPRQ_EN, MLX5_RX_MPRQ_LOG_STRIDE_NUM, MLX5_RX_MPRQ_MAX_MEMCPY_LEN, @@ -735,6 +741,7 @@ mlx5_dev_spawn(struct rte_device *dpdk_dev, struct rte_eth_dev *eth_dev = NULL; struct priv *priv = NULL; int err = 0; + unsigned int hw_padding = 0; unsigned int mps; unsigned int cqe_comp; unsigned int cqe_pad = 0; @@ -1060,10 +1067,14 @@ mlx5_dev_spawn(struct rte_device *dpdk_dev, DRV_LOG(DEBUG, "FCS stripping configuration is %ssupported", (config.hw_fcs_strip ? "" : "not ")); #ifdef HAVE_IBV_WQ_FLAG_RX_END_PADDING - config.hw_padding = !!attr.rx_pad_end_addr_align; + hw_padding = !!attr.rx_pad_end_addr_align; #endif - DRV_LOG(DEBUG, "hardware Rx end alignment padding is %ssupported", - (config.hw_padding ? "" : "not ")); + if (config.hw_padding && !hw_padding) { + DRV_LOG(DEBUG, "Rx end alignment padding isn't supported"); + config.hw_padding = 0; + } else if (config.hw_padding) { + DRV_LOG(DEBUG, "Rx end alignment padding is enabled"); + } config.tso = (attr.tso_caps.max_tso > 0 && (attr.tso_caps.supported_qpts & (1 << IBV_QPT_RAW_PACKET))); @@ -1440,6 +1451,7 @@ mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused, qsort(list, n, sizeof(*list), mlx5_dev_spawn_data_cmp); /* Default configuration. */ dev_config = (struct mlx5_dev_config){ + .hw_padding = 0, .mps = MLX5_ARG_UNSET, .tx_vec_en = 1, .rx_vec_en = 1, -- 2.20.1