From: Shahaf Shuler Date: Sun, 27 Aug 2017 06:47:09 +0000 (+0300) Subject: net/mlx5: don't map doorbell register to write combining X-Git-Tag: spdx-start~2088 X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=9f9bebae5530;p=dpdk.git net/mlx5: don't map doorbell register to write combining By default, Verbs maps the doorbell register to write combining. Working with write combining is useful for drivers which use blue flame for the doorbell write. Since mlx5 PMD uses only doorbells and write combining mapping requires an extra memory barrier to flush the doorbell after its write, setting the mapping to un-cached by default. Such change is expected to reduce the max and average round trip latency. Signed-off-by: Shahaf Shuler Signed-off-by: Yongseok Koh Signed-off-by: Alexander Solganik Signed-off-by: Sagi Grimberg Acked-by: Nelio Laranjeiro --- diff --git a/drivers/net/mlx5/mlx5.c b/drivers/net/mlx5/mlx5.c index bd66a7c77a..50f4ba70a3 100644 --- a/drivers/net/mlx5/mlx5.c +++ b/drivers/net/mlx5/mlx5.c @@ -884,6 +884,8 @@ rte_mlx5_pmd_init(void) * using this PMD, which is not supported in forked processes. */ setenv("RDMAV_HUGEPAGES_SAFE", "1", 1); + /* Don't map UAR to WC if BlueFlame is not used.*/ + setenv("MLX5_SHUT_UP_BF", "1", 1); ibv_fork_init(); rte_pci_register(&mlx5_driver); }