diff options
| author | Chuck Lever <chuck.lever@oracle.com> | 2018-12-19 10:58:51 -0500 |
|---|---|---|
| committer | Anna Schumaker <Anna.Schumaker@Netapp.com> | 2019-01-02 12:05:17 -0500 |
| commit | a78868497c2e4858e2c73818eed7b4877ab2316d (patch) | |
| tree | 9d57c46b0b6584e3d60524deb345865d0142a980 | |
| parent | 6946f82380a83acb7023fab9d7033e1f016cb818 (diff) | |
xprtrdma: Reduce max_frwr_depth
Some devices advertise a large max_fast_reg_page_list_len
capability, but perform optimally when MRs are significantly smaller
than that depth -- probably when the MR itself is no larger than a
page.
By default, the RDMA R/W core API uses max_sge_rd as the maximum
page depth for MRs. For some devices, the value of max_sge_rd is
1, which is also not optimal. Thus, when max_sge_rd is larger than
1, use that value. Otherwise use the value of the
max_fast_reg_page_list_len attribute.
I've tested this with CX-3 Pro, FastLinq, and CX-5 devices. It
reproducibly improves the throughput of large I/Os by several
percent.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
| -rw-r--r-- | net/sunrpc/xprtrdma/frwr_ops.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c index f587e445d811..16976b031865 100644 --- a/net/sunrpc/xprtrdma/frwr_ops.c +++ b/net/sunrpc/xprtrdma/frwr_ops.c @@ -193,10 +193,17 @@ frwr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep, if (attrs->device_cap_flags & IB_DEVICE_SG_GAPS_REG) ia->ri_mrtype = IB_MR_TYPE_SG_GAPS; - ia->ri_max_frwr_depth = - min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS, - attrs->max_fast_reg_page_list_len); - dprintk("RPC: %s: device's max FR page list len = %u\n", + /* Quirk: Some devices advertise a large max_fast_reg_page_list_len + * capability, but perform optimally when the MRs are not larger + * than a page. + */ + if (attrs->max_sge_rd > 1) + ia->ri_max_frwr_depth = attrs->max_sge_rd; + else + ia->ri_max_frwr_depth = attrs->max_fast_reg_page_list_len; + if (ia->ri_max_frwr_depth > RPCRDMA_MAX_DATA_SEGS) + ia->ri_max_frwr_depth = RPCRDMA_MAX_DATA_SEGS; + dprintk("RPC: %s: max FR page list depth = %u\n", __func__, ia->ri_max_frwr_depth); /* Add room for frwr register and invalidate WRs. |