From: Yangyang Li liyangyang20@huawei.com
[ Upstream commit 56518a603fd2bf74762d176ac980572db84a3e14 ]
Long message loopback slice is used for achieving traffic balance between QPs. It prevents the problem that QPs with large traffic occupying the hardware pipeline for a long time and QPs with small traffic cannot be scheduled.
Currently, its maximum value is set to 16K, which means only after a QP sends 16K will the second QP be scheduled. This value is too large, which will lead to unbalanced traffic scheduling, and thus it needs to be modified.
The setting range of the long message loopback slice is modified to be from 1024 (the lower limit supported by hardware) to mtu. Actual testing shows that this value can significantly reduce error in hardware traffic scheduling.
This solution is compatible with both HIP08 and HIP09. The modified lp_pktn_ini has a maximum value of 2 (when mtu is 256), so the range checking code for lp_pktn_ini is no longer necessary and needs to be deleted.
Fixes: 0e60778efb07 ("RDMA/hns: Modify the value of MAX_LP_MSG_LEN to meet hardware compatibility") Link: https://lore.kernel.org/r/20230512092245.344442-4-huangjunxian6@hisilicon.co... Signed-off-by: Yangyang Li liyangyang20@huawei.com Signed-off-by: Junxian Huang huangjunxian6@hisilicon.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/infiniband/hw/hns/hns_roce_hw_v2.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c index 79d92b7899849..8c02b51c8bffc 100644 --- a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c +++ b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c @@ -4393,11 +4393,9 @@ static int modify_qp_init_to_rtr(struct ib_qp *ibqp, mtu = ib_mtu_enum_to_int(ib_mtu); if (WARN_ON(mtu <= 0)) return -EINVAL; -#define MAX_LP_MSG_LEN 16384 - /* MTU * (2 ^ LP_PKTN_INI) shouldn't be bigger than 16KB */ - lp_pktn_ini = ilog2(MAX_LP_MSG_LEN / mtu); - if (WARN_ON(lp_pktn_ini >= 0xF)) - return -EINVAL; +#define MIN_LP_MSG_LEN 1024 + /* mtu * (2 ^ lp_pktn_ini) should be in the range of 1024 to mtu */ + lp_pktn_ini = ilog2(max(mtu, MIN_LP_MSG_LEN) / mtu);
if (attr_mask & IB_QP_PATH_MTU) { hr_reg_write(context, QPC_MTU, ib_mtu);