Hi, I am trying to understand the uuar-related calculations of the userspace mlx5 driver (in mlx5_alloc_context) that use the various constants introduced in https://github.com/linux-rdma/rdma-core/commit/166d34841dd6a835e4f4f0196143880a73ce71bd. My understanding is that a uar is comprised of uuars. bfregs mean the same thing as uuars. A doorbell is written to the bfreg/uuar assigned to the QP. (1) W.r.t. MLX5_NUM_NON_FP_BFREGS_PER_UAR, what is a NON_FP_BFREG in a UAR? I am curious to know what FP stands for. (2) Is the value of NUM_BFREGS_PER_UAR set to 4 because the driver will have at least 4 low_lat_uuars for a context? This constant is used only in the calculation of gross_uuars. My assumption is that the NUM_BFREGS_PER_UAR value is not specific to the mlx5 device because of the missing MLX5_ prefix. Please correct me if I am wrong. (3) Given that the value of tot_uuars and low_lat_uuars can be configured through the MLX5_TOTAL_UUARS and MLX5_NUM_LOW_LAT_UUARS environment variables respectively, it is possible for me to have, in 1 context, 512 tot_uuars (=MLX5_MAX_BFREGS) and set all 511 of them as low_lat_uuars. Is this correct? Thanks, Rohit Zambre Ph.D. Student, Computer Engineering University of California, Irvine -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
