Instead of using a fixed number, allow the amount of Send completion
batching to vary based on the client's maximum credit limit.
- A larger default gives a small boost to IOPS throughput
- Reducing it based on max_requests gives a safe result when the
max credit limit is cranked down (eg. when the device has a small
max_qp_wr).
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
net/sunrpc/xprtrdma/verbs.c | 4 +---
net/sunrpc/xprtrdma/xprt_rdma.h | 10 ----------
2 files changed, 1 insertion(+), 13 deletions(-)
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 1ad2519..1ed761a 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -521,9 +521,7 @@ static void rpcrdma_xprt_drain(struct rpcrdma_xprt *r_xprt)
ep->rep_attr.cap.max_send_sge,
ep->rep_attr.cap.max_recv_sge);
- /* set trigger for requesting send completion */
- ep->rep_send_batch = min_t(unsigned int, RPCRDMA_MAX_SEND_BATCH,
- cdata->max_requests >> 2);
+ ep->rep_send_batch = cdata->max_requests >> 3;
ep->rep_send_count = ep->rep_send_batch;
init_waitqueue_head(&ep->rep_connect_wait);
ep->rep_receive_count = 0;
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 8afb5fc..f856393 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -232,16 +232,6 @@ struct rpcrdma_sendctx {
struct ib_sge sc_sges[];
};
-/* Limit the number of SGEs that can be unmapped during one
- * Send completion. This caps the amount of work a single
- * completion can do before returning to the provider.
- *
- * Setting this to zero disables Send completion batching.
- */
-enum {
- RPCRDMA_MAX_SEND_BATCH = 7,
-};
-
/*
* struct rpcrdma_mr - external memory region metadata
*
