Commit e936a597 authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

SUNRPC: Add tracepoint that fires when an RPC is retransmitted 



A separate tracepoint can be left enabled all the time to capture
rare but important retransmission events. So for example:

kworker/u26:3-568   [009]   156.967933: xprt_retransmit:      task:44093@5 xid=0xa25dbc79 nfsv3 WRITE ntrans=2

Or, for example, enable all nfs and nfs4 tracepoints, and set up a
trigger to disable tracing when xprt_retransmit fires to capture
everything that leads up to it.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent 7638e0bf

include/trace/events/sunrpc.h

+40 −0
Original line number Diff line number Diff line
@@ -1079,6 +1079,46 @@ TRACE_EVENT(xprt_transmit, 
		__entry->seqno, __entry->status)

);



TRACE_EVENT(xprt_retransmit,

	TP_PROTO(

		const struct rpc_rqst *rqst

	),



	TP_ARGS(rqst),



	TP_STRUCT__entry(

		__field(unsigned int, task_id)

		__field(unsigned int, client_id)

		__field(u32, xid)

		__field(int, ntrans)

		__field(int, version)

		__string(progname,

			 rqst->rq_task->tk_client->cl_program->name)

		__string(procedure,

			 rqst->rq_task->tk_msg.rpc_proc->p_name)

	),



	TP_fast_assign(

		struct rpc_task *task = rqst->rq_task;



		__entry->task_id = task->tk_pid;

		__entry->client_id = task->tk_client ?

			task->tk_client->cl_clid : -1;

		__entry->xid = be32_to_cpu(rqst->rq_xid);

		__entry->ntrans = rqst->rq_ntrans;

		__assign_str(progname,

			     task->tk_client->cl_program->name)

		__entry->version = task->tk_client->cl_vers;

		__assign_str(procedure, task->tk_msg.rpc_proc->p_name)

	),



	TP_printk(

		"task:%u@%u xid=0x%08x %sv%d %s ntrans=%d",

		__entry->task_id, __entry->client_id, __entry->xid,

		__get_str(progname), __entry->version, __get_str(procedure),

		__entry->ntrans)

);



TRACE_EVENT(xprt_ping,

	TP_PROTO(const struct rpc_xprt *xprt, int status),

net/sunrpc/xprt.c

+3 −1
Original line number Diff line number Diff line
@@ -1542,8 +1542,10 @@ xprt_request_transmit(struct rpc_rqst *req, struct rpc_task *snd_task) 
		return status;

	}



	if (is_retrans)

	if (is_retrans) {

		task->tk_client->cl_stats->rpcretrans++;

		trace_xprt_retransmit(req);

	}



	xprt_inject_disconnect(xprt);