From c5f714e50b0ecac6a6b2de4722f8bd1a7f4ab29f Mon Sep 17 00:00:00 2001 From: Matan Azrad Date: Mon, 29 Jun 2020 14:01:55 +0000 Subject: [PATCH] vdpa/mlx5: optimize completion queue poll The vDPA driver uses a CQ in order to know when traffic works were completed by the HW. Each traffic burst completion adds a CQE to the CQ. When the vDPA driver detects CQEs in the CQ, it triggers the guest notification for the corresponding queue and consumes all of them. There is collapse feature in the HW that configures the HW to write all the CQEs in the first entry of the CQ. Using this feature, the vDPA driver can read only the first CQE, validate that the completion counter inside the CQE was changed and if so, to notify the guest. Use CQ collapse feature in order to improve the poll utilization. Signed-off-by: Matan Azrad Reviewed-by: Maxime Coquelin --- drivers/vdpa/mlx5/mlx5_vdpa_event.c | 73 ++++++++++++++++------------- 1 file changed, 40 insertions(+), 33 deletions(-) diff --git a/drivers/vdpa/mlx5/mlx5_vdpa_event.c b/drivers/vdpa/mlx5/mlx5_vdpa_event.c index 743e52a6d5..1c9f939cc3 100644 --- a/drivers/vdpa/mlx5/mlx5_vdpa_event.c +++ b/drivers/vdpa/mlx5/mlx5_vdpa_event.c @@ -127,12 +127,12 @@ mlx5_vdpa_cq_create(struct mlx5_vdpa_priv *priv, uint16_t log_desc_n, struct mlx5_devx_cq_attr attr; size_t pgsize = sysconf(_SC_PAGESIZE); uint32_t umem_size; - int ret; uint16_t event_nums[1] = {0}; + uint16_t cq_size = 1 << log_desc_n; + int ret; cq->log_desc_n = log_desc_n; - umem_size = sizeof(struct mlx5_cqe) * (1 << log_desc_n) + - sizeof(*cq->db_rec) * 2; + umem_size = sizeof(struct mlx5_cqe) * cq_size + sizeof(*cq->db_rec) * 2; cq->umem_buf = rte_zmalloc(__func__, umem_size, 4096); if (!cq->umem_buf) { DRV_LOG(ERR, "Failed to allocate memory for CQ."); @@ -149,13 +149,13 @@ mlx5_vdpa_cq_create(struct mlx5_vdpa_priv *priv, uint16_t log_desc_n, } attr.q_umem_valid = 1; attr.db_umem_valid = 1; - attr.use_first_only = 0; + attr.use_first_only = 1; attr.overrun_ignore = 0; attr.uar_page_id = priv->uar->page_id; attr.q_umem_id = cq->umem_obj->umem_id; attr.q_umem_offset = 0; attr.db_umem_id = cq->umem_obj->umem_id; - attr.db_umem_offset = sizeof(struct mlx5_cqe) * (1 << log_desc_n); + attr.db_umem_offset = sizeof(struct mlx5_cqe) * cq_size; attr.eqn = priv->eqn; attr.log_cq_size = log_desc_n; attr.log_page_size = rte_log2_u32(pgsize); @@ -187,7 +187,8 @@ mlx5_vdpa_cq_create(struct mlx5_vdpa_priv *priv, uint16_t log_desc_n, } cq->callfd = callfd; /* Init CQ to ones to be in HW owner in the start. */ - memset((void *)(uintptr_t)cq->umem_buf, 0xFF, attr.db_umem_offset); + cq->cqes[0].op_own = MLX5_CQE_OWNER_MASK; + cq->cqes[0].wqe_counter = rte_cpu_to_be_16(cq_size - 1); /* First arming. */ mlx5_vdpa_cq_arm(priv, cq); return 0; @@ -203,34 +204,40 @@ mlx5_vdpa_cq_poll(struct mlx5_vdpa_cq *cq) container_of(cq, struct mlx5_vdpa_event_qp, cq); const unsigned int cq_size = 1 << cq->log_desc_n; const unsigned int cq_mask = cq_size - 1; - uint32_t total = 0; - int ret; - - do { - volatile struct mlx5_cqe *cqe = cq->cqes + ((cq->cq_ci + total) - & cq_mask); - - ret = check_cqe(cqe, cq_size, cq->cq_ci + total); - switch (ret) { - case MLX5_CQE_STATUS_ERR: + union { + struct { + uint16_t wqe_counter; + uint8_t rsvd5; + uint8_t op_own; + }; + uint32_t word; + } last_word; + uint16_t next_wqe_counter = cq->cq_ci & cq_mask; + uint16_t cur_wqe_counter; + uint16_t comp; + + last_word.word = rte_read32(&cq->cqes[0].wqe_counter); + cur_wqe_counter = rte_be_to_cpu_16(last_word.wqe_counter); + comp = (cur_wqe_counter + 1u - next_wqe_counter) & cq_mask; + if (comp) { + cq->cq_ci += comp; + MLX5_ASSERT(!!(cq->cq_ci & cq_size) == + MLX5_CQE_OWNER(last_word.op_own)); + MLX5_ASSERT(MLX5_CQE_OPCODE(last_word.op_own) != + MLX5_CQE_INVALID); + if (unlikely(!(MLX5_CQE_OPCODE(last_word.op_own) == + MLX5_CQE_RESP_ERR || + MLX5_CQE_OPCODE(last_word.op_own) == + MLX5_CQE_REQ_ERR))) cq->errors++; - /*fall-through*/ - case MLX5_CQE_STATUS_SW_OWN: - total++; - break; - case MLX5_CQE_STATUS_HW_OWN: - default: - break; - } - } while (ret != MLX5_CQE_STATUS_HW_OWN); - rte_io_wmb(); - cq->cq_ci += total; - /* Ring CQ doorbell record. */ - cq->db_rec[0] = rte_cpu_to_be_32(cq->cq_ci); - rte_io_wmb(); - /* Ring SW QP doorbell record. */ - eqp->db_rec[0] = rte_cpu_to_be_32(cq->cq_ci + cq_size); - return total; + rte_io_wmb(); + /* Ring CQ doorbell record. */ + cq->db_rec[0] = rte_cpu_to_be_32(cq->cq_ci); + rte_io_wmb(); + /* Ring SW QP doorbell record. */ + eqp->db_rec[0] = rte_cpu_to_be_32(cq->cq_ci + cq_size); + } + return comp; } static void -- 2.20.1