Commit bf7ca707 authored by Chuck Lever's avatar Chuck Lever Committed by Anna Schumaker
Browse files

SUNRPC: Add trace points to observe transport congestion control 



To help debug problems with RPC/RDMA credit management, replace
dprintk() call sites in the transport send lock paths with trace
events.

Similar trace points are defined for the non-congestion paths.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 5cd8b0d4

include/trace/events/sunrpc.h

+93 −0
Original line number Diff line number Diff line
@@ -777,6 +777,99 @@ TRACE_EVENT(xprt_ping, 
			__get_str(addr), __get_str(port), __entry->status)

);



DECLARE_EVENT_CLASS(xprt_writelock_event,

	TP_PROTO(

		const struct rpc_xprt *xprt, const struct rpc_task *task

	),



	TP_ARGS(xprt, task),



	TP_STRUCT__entry(

		__field(unsigned int, task_id)

		__field(unsigned int, client_id)

		__field(unsigned int, snd_task_id)

	),



	TP_fast_assign(

		if (task) {

			__entry->task_id = task->tk_pid;

			__entry->client_id = task->tk_client ?

					     task->tk_client->cl_clid : -1;

		} else {

			__entry->task_id = -1;

			__entry->client_id = -1;

		}

		__entry->snd_task_id = xprt->snd_task ?

					xprt->snd_task->tk_pid : -1;

	),



	TP_printk("task:%u@%u snd_task:%u",

			__entry->task_id, __entry->client_id,

			__entry->snd_task_id)

);



#define DEFINE_WRITELOCK_EVENT(name) \

	DEFINE_EVENT(xprt_writelock_event, xprt_##name, \

			TP_PROTO( \

				const struct rpc_xprt *xprt, \

				const struct rpc_task *task \

			), \

			TP_ARGS(xprt, task))



DEFINE_WRITELOCK_EVENT(reserve_xprt);

DEFINE_WRITELOCK_EVENT(release_xprt);



DECLARE_EVENT_CLASS(xprt_cong_event,

	TP_PROTO(

		const struct rpc_xprt *xprt, const struct rpc_task *task

	),



	TP_ARGS(xprt, task),



	TP_STRUCT__entry(

		__field(unsigned int, task_id)

		__field(unsigned int, client_id)

		__field(unsigned int, snd_task_id)

		__field(unsigned long, cong)

		__field(unsigned long, cwnd)

		__field(bool, wait)

	),



	TP_fast_assign(

		if (task) {

			__entry->task_id = task->tk_pid;

			__entry->client_id = task->tk_client ?

					     task->tk_client->cl_clid : -1;

		} else {

			__entry->task_id = -1;

			__entry->client_id = -1;

		}

		__entry->snd_task_id = xprt->snd_task ?

					xprt->snd_task->tk_pid : -1;

		__entry->cong = xprt->cong;

		__entry->cwnd = xprt->cwnd;

		__entry->wait = test_bit(XPRT_CWND_WAIT, &xprt->state);

	),



	TP_printk("task:%u@%u snd_task:%u cong=%lu cwnd=%lu%s",

			__entry->task_id, __entry->client_id,

			__entry->snd_task_id, __entry->cong, __entry->cwnd,

			__entry->wait ? " (wait)" : "")

);



#define DEFINE_CONG_EVENT(name) \

	DEFINE_EVENT(xprt_cong_event, xprt_##name, \

			TP_PROTO( \

				const struct rpc_xprt *xprt, \

				const struct rpc_task *task \

			), \

			TP_ARGS(xprt, task))



DEFINE_CONG_EVENT(reserve_cong);

DEFINE_CONG_EVENT(release_cong);

DEFINE_CONG_EVENT(get_cong);

DEFINE_CONG_EVENT(put_cong);



TRACE_EVENT(xs_stream_read_data,

	TP_PROTO(struct rpc_xprt *xprt, ssize_t err, size_t total),

net/sunrpc/xprt.c

+13 −9
Original line number Diff line number Diff line
@@ -205,20 +205,20 @@ int xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task) 


	if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {

		if (task == xprt->snd_task)

			return 1;

			goto out_locked;

		goto out_sleep;

	}

	if (test_bit(XPRT_WRITE_SPACE, &xprt->state))

		goto out_unlock;

	xprt->snd_task = task;



out_locked:

	trace_xprt_reserve_xprt(xprt, task);

	return 1;



out_unlock:

	xprt_clear_locked(xprt);

out_sleep:

	dprintk("RPC: %5u failed to lock transport %p\n",

			task->tk_pid, xprt);

	task->tk_status = -EAGAIN;

	if  (RPC_IS_SOFT(task))

		rpc_sleep_on_timeout(&xprt->sending, task, NULL,
@@ -269,23 +269,22 @@ int xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task) 


	if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {

		if (task == xprt->snd_task)

			return 1;

			goto out_locked;

		goto out_sleep;

	}

	if (req == NULL) {

		xprt->snd_task = task;

		return 1;

		goto out_locked;

	}

	if (test_bit(XPRT_WRITE_SPACE, &xprt->state))

		goto out_unlock;

	if (!xprt_need_congestion_window_wait(xprt)) {

		xprt->snd_task = task;

		return 1;

		goto out_locked;

	}

out_unlock:

	xprt_clear_locked(xprt);

out_sleep:

	dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt);

	task->tk_status = -EAGAIN;

	if (RPC_IS_SOFT(task))

		rpc_sleep_on_timeout(&xprt->sending, task, NULL,
@@ -293,6 +292,9 @@ out_sleep: 
	else

		rpc_sleep_on(&xprt->sending, task, NULL);

	return 0;

out_locked:

	trace_xprt_reserve_cong(xprt, task);

	return 1;

}

EXPORT_SYMBOL_GPL(xprt_reserve_xprt_cong);
@@ -357,6 +359,7 @@ void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task) 
		xprt_clear_locked(xprt);

		__xprt_lock_write_next(xprt);

	}

	trace_xprt_release_xprt(xprt, task);

}

EXPORT_SYMBOL_GPL(xprt_release_xprt);
@@ -374,6 +377,7 @@ void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task) 
		xprt_clear_locked(xprt);

		__xprt_lock_write_next_cong(xprt);

	}

	trace_xprt_release_cong(xprt, task);

}

EXPORT_SYMBOL_GPL(xprt_release_xprt_cong);
@@ -395,8 +399,7 @@ __xprt_get_cong(struct rpc_xprt *xprt, struct rpc_rqst *req) 
{

	if (req->rq_cong)

		return 1;

	dprintk("RPC: %5u xprt_cwnd_limited cong = %lu cwnd = %lu\n",

			req->rq_task->tk_pid, xprt->cong, xprt->cwnd);

	trace_xprt_get_cong(xprt, req->rq_task);

	if (RPCXPRT_CONGESTED(xprt)) {

		xprt_set_congestion_window_wait(xprt);

		return 0;
@@ -418,6 +421,7 @@ __xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req) 
	req->rq_cong = 0;

	xprt->cong -= RPC_CWNDSCALE;

	xprt_test_and_clear_congestion_window_wait(xprt);

	trace_xprt_put_cong(xprt, req->rq_task);

	__xprt_lock_write_next_cong(xprt);

}

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