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: Chuck Lever <[email protected]>
---
include/trace/events/sunrpc.h | 40 ++++++++++++++++++++++++++++++++++++++++
net/sunrpc/xprt.c | 4 +++-
2 files changed, 43 insertions(+), 1 deletion(-)
diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 2f01314de73a..3c3c4c843c62 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -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),
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 11ebe8a127b8..43bc093c66b9 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1538,8 +1538,10 @@ 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);