RDMA/rw: Support threshold for registration vs scattering to local pages

If there are more scatter entries than the recommended limit provided by
the ib device, UMR registration is used. This will provide optimal
performance when performing large RDMA READs over devices that advertise
the threshold capability.

With ConnectX-5 running NVMeoF RDMA with FIO single QP 128KB writes:
Without use of cap: 70Gb/sec
With use of cap: 84Gb/sec

Link: https://lore.kernel.org/r/20191007135933.12483-3-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>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Yamin Friedman
2019-10-07 16:59:32 +03:00
committed by Jason Gunthorpe
parent 7d47433cf7
commit 00bd1439f4
2 changed files with 17 additions and 10 deletions

View File

@@ -445,6 +445,8 @@ struct ib_device_attr {
struct ib_tm_caps tm_caps;
struct ib_cq_caps cq_caps;
u64 max_dm_size;
/* Max entries for sgl for optimized performance per READ */
u32 max_sgl_rd;
};
enum ib_mtu {