Commit 78215759 authored by Chuck Lever's avatar Chuck Lever Committed by Anna Schumaker
Browse files

SUNRPC: Make RTT measurement more precise (Send) 



Some RPC transports have more overhead in their send_request
callouts than others. For example, for RPC-over-RDMA:

- Marshaling an RPC often has to DMA map the RPC arguments

- Registration methods perform memory registration as part of
  marshaling

To capture just server and network latencies more precisely: when
sending a Call, capture the rq_xtime timestamp _after_ the transport
header has been marshaled.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 0b87a46b

net/sunrpc/xprt.c

+0 −1
Original line number Diff line number Diff line
@@ -1033,7 +1033,6 @@ void xprt_transmit(struct rpc_task *task) 
		return;



	connect_cookie = xprt->connect_cookie;

	req->rq_xtime = ktime_get();

	status = xprt->ops->send_request(task);

	trace_xprt_transmit(xprt, req->rq_xid, status);

	if (status != 0) {

net/sunrpc/xprtrdma/transport.c

+1 −0
Original line number Diff line number Diff line
@@ -696,6 +696,7 @@ xprt_rdma_send_request(struct rpc_task *task) 
	/* Must suppress retransmit to maintain credits */

	if (rqst->rq_connect_cookie == xprt->connect_cookie)

		goto drop_connection;

	rqst->rq_xtime = ktime_get();



	__set_bit(RPCRDMA_REQ_F_PENDING, &req->rl_flags);

	if (rpcrdma_ep_post(&r_xprt->rx_ia, &r_xprt->rx_ep, req))

net/sunrpc/xprtsock.c

+3 −0
Original line number Diff line number Diff line
@@ -527,6 +527,7 @@ static int xs_local_send_request(struct rpc_task *task) 
	xs_pktdump("packet data:",

			req->rq_svec->iov_base, req->rq_svec->iov_len);



	req->rq_xtime = ktime_get();

	status = xs_sendpages(transport->sock, NULL, 0, xdr, req->rq_bytes_sent,

			      true, &sent);

	dprintk("RPC:       %s(%u) = %d\n",
@@ -589,6 +590,7 @@ static int xs_udp_send_request(struct rpc_task *task) 


	if (!xprt_bound(xprt))

		return -ENOTCONN;

	req->rq_xtime = ktime_get();

	status = xs_sendpages(transport->sock, xs_addr(xprt), xprt->addrlen,

			      xdr, req->rq_bytes_sent, true, &sent);
@@ -678,6 +680,7 @@ static int xs_tcp_send_request(struct rpc_task *task) 
	/* Continue transmitting the packet/record. We must be careful

	 * to cope with writespace callbacks arriving _after_ we have

	 * called sendmsg(). */

	req->rq_xtime = ktime_get();

	while (1) {

		sent = 0;

		status = xs_sendpages(transport->sock, NULL, 0, xdr,

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