RDMA/mlx5: Add capability for max sge to get optimized performance

Allows the IB device to provide a value of maximum scatter gather entries
per RDMA READ.

In certain cases it may be preferable for a device to perform UMR memory
registration rather than have many scatter entries in a single RDMA READ.
This provides a significant performance increase in devices capable of
using different memory registration schemes based on the number of scatter
gather entries. This general capability allows each device vendor to fine
tune when it is better to use memory registration.

Link: https://lore.kernel.org/r/20191007135933.12483-4-leon@kernel.org
Signed-off-by: Yamin Friedman <yaminf@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Yamin Friedman 2019-10-07 16:59:33 +03:00 committed by Jason Gunthorpe
parent 00bd1439f4
commit 366090564b
1 changed files with 2 additions and 0 deletions

View File

@ -1011,6 +1011,8 @@ static int mlx5_ib_query_device(struct ib_device *ibdev,
1 << MLX5_CAP_GEN(mdev, log_max_klm_list_size);
props->max_pi_fast_reg_page_list_len =
props->max_fast_reg_page_list_len / 2;
props->max_sgl_rd =
MLX5_CAP_GEN(mdev, max_sgl_for_optimized_performance);
get_atomic_caps_qp(dev, props);
props->masked_atomic_cap = IB_ATOMIC_NONE;
props->max_mcast_grp = 1 << MLX5_CAP_GEN(mdev, log_max_mcg);