diff options
| author | Chuck Lever <chuck.lever@oracle.com> | 2019-02-11 11:23:54 -0500 |
|---|---|---|
| committer | Anna Schumaker <Anna.Schumaker@Netapp.com> | 2019-02-13 10:30:11 -0500 |
| commit | e340c2d6ef2a8cdcc11672f8cc839c30ad360e52 (patch) | |
| tree | 66f79ef669fdbc3358afa4e2a017cca6c70688d5 /net | |
| parent | d4550bbee66f4ba5a5e9bbe8055006332ebfc58b (diff) | |
xprtrdma: Reduce the doorbell rate (Receive)
Post RECV WRs in batches to reduce the hardware doorbell rate per
transport. This helps the RPC-over-RDMA client scale better in
number of transports.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/sunrpc/xprtrdma/verbs.c | 2 | ||||
| -rw-r--r-- | net/sunrpc/xprtrdma/xprt_rdma.h | 10 |
2 files changed, 12 insertions, 0 deletions
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index 4994e75945b8..b4e997d53ec7 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -1480,6 +1480,8 @@ rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, bool temp) if (ep->rep_receive_count > needed) goto out; needed -= ep->rep_receive_count; + if (!temp) + needed += RPCRDMA_MAX_RECV_BATCH; count = 0; wr = NULL; diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h index 33db208fa9a8..10f6593e1a6a 100644 --- a/net/sunrpc/xprtrdma/xprt_rdma.h +++ b/net/sunrpc/xprtrdma/xprt_rdma.h @@ -205,6 +205,16 @@ struct rpcrdma_rep { struct ib_recv_wr rr_recv_wr; }; +/* To reduce the rate at which a transport invokes ib_post_recv + * (and thus the hardware doorbell rate), xprtrdma posts Receive + * WRs in batches. + * + * Setting this to zero disables Receive post batching. + */ +enum { + RPCRDMA_MAX_RECV_BATCH = 7, +}; + /* struct rpcrdma_sendctx - DMA mapped SGEs to unmap after Send completes */ struct rpcrdma_req; |