[PATCH v2 02/12] sunrpc: add info about xprt queue times to svc_xprt_dequeue tracepoint

[Jeff Layton]

Currently, this tracepoint displays "wakeup-us", which is the time that
the woken thread spent sleeping, before dequeueing the next xprt. Add a
new statistic that shows how long the xprt sat on the queue before being
serviced.

Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
 include/linux/sunrpc/svc_xprt.h |  1 +
 include/trace/events/sunrpc.h   | 13 +++++++------
 net/sunrpc/svc_xprt.c           |  1 +
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index 72be609525796792274d5b8cb5ff37f73723fc23..369a89aea18618748607ee943247c327bf62c8d5 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -53,6 +53,7 @@ struct svc_xprt {
 	struct svc_xprt_class	*xpt_class;
 	const struct svc_xprt_ops *xpt_ops;
 	struct kref		xpt_ref;
+	ktime_t			xpt_qtime;
 	struct list_head	xpt_list;
 	struct lwq_node		xpt_ready;
 	unsigned long		xpt_flags;
diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 5d331383047b79b9f6dcd699c87287453c1a5f49..b5a0f0bc1a3b7cfd90ce0181a8a419db810988bb 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -2040,19 +2040,20 @@ TRACE_EVENT(svc_xprt_dequeue,
 
 	TP_STRUCT__entry(
 		SVC_XPRT_ENDPOINT_FIELDS(rqst->rq_xprt)
-
 		__field(unsigned long, wakeup)
+		__field(unsigned long, qtime)
 	),
 
 	TP_fast_assign(
-		SVC_XPRT_ENDPOINT_ASSIGNMENTS(rqst->rq_xprt);
+		ktime_t ktime = ktime_get();
 
-		__entry->wakeup = ktime_to_us(ktime_sub(ktime_get(),
-							rqst->rq_qtime));
+		SVC_XPRT_ENDPOINT_ASSIGNMENTS(rqst->rq_xprt);
+		__entry->wakeup = ktime_to_us(ktime_sub(ktime, rqst->rq_qtime));
+		__entry->qtime = ktime_to_us(ktime_sub(ktime, rqst->rq_xprt->xpt_qtime));
 	),
 
-	TP_printk(SVC_XPRT_ENDPOINT_FORMAT " wakeup-us=%lu",
-		SVC_XPRT_ENDPOINT_VARARGS, __entry->wakeup)
+	TP_printk(SVC_XPRT_ENDPOINT_FORMAT " wakeup-us=%lu qtime=%lu",
+		SVC_XPRT_ENDPOINT_VARARGS, __entry->wakeup, __entry->qtime)
 );
 
 DECLARE_EVENT_CLASS(svc_xprt_event,
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index ae25405d8bd22672a361d1fd3adfdcebb403f90f..32018557797b1f683d8b7259f5fccd029aebcd71 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -488,6 +488,7 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
 	pool = svc_pool_for_cpu(xprt->xpt_server);
 
 	percpu_counter_inc(&pool->sp_sockets_queued);
+	xprt->xpt_qtime = ktime_get();
 	lwq_enqueue(&xprt->xpt_ready, &pool->sp_xprts);
 
 	svc_pool_wake_idle_thread(pool);

-- 
2.49.0