1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 *  linux/include/linux/sunrpc/metrics.h
4 *
5 *  Declarations for RPC client per-operation metrics
6 *
7 *  Copyright (C) 2005	Chuck Lever <cel@netapp.com>
8 *
9 *  RPC client per-operation statistics provide latency and retry
10 *  information about each type of RPC procedure in a given RPC program.
11 *  These statistics are not for detailed problem diagnosis, but simply
12 *  to indicate whether the problem is local or remote.
13 *
14 *  These counters are not meant to be human-readable, but are meant to be
15 *  integrated into system monitoring tools such as "sar" and "iostat".  As
16 *  such, the counters are sampled by the tools over time, and are never
17 *  zeroed after a file system is mounted.  Moving averages can be computed
18 *  by the tools by taking the difference between two instantaneous samples
19 *  and dividing that by the time between the samples.
20 *
21 *  The counters are maintained in a single array per RPC client, indexed
22 *  by procedure number.  There is no need to maintain separate counter
23 *  arrays per-CPU because these counters are always modified behind locks.
24 */
25
26#ifndef _LINUX_SUNRPC_METRICS_H
27#define _LINUX_SUNRPC_METRICS_H
28
29#include <linux/seq_file.h>
30#include <linux/ktime.h>
31#include <linux/spinlock.h>
32
33#define RPC_IOSTATS_VERS	"1.1"
34
35struct rpc_iostats {
36	spinlock_t		om_lock;
37
38	/*
39	 * These counters give an idea about how many request
40	 * transmissions are required, on average, to complete that
41	 * particular procedure.  Some procedures may require more
42	 * than one transmission because the server is unresponsive,
43	 * the client is retransmitting too aggressively, or the
44	 * requests are large and the network is congested.
45	 */
46	unsigned long		om_ops,		/* count of operations */
47				om_ntrans,	/* count of RPC transmissions */
48				om_timeouts;	/* count of major timeouts */
49
50	/*
51	 * These count how many bytes are sent and received for a
52	 * given RPC procedure type.  This indicates how much load a
53	 * particular procedure is putting on the network.  These
54	 * counts include the RPC and ULP headers, and the request
55	 * payload.
56	 */
57	unsigned long long      om_bytes_sent,	/* count of bytes out */
58				om_bytes_recv;	/* count of bytes in */
59
60	/*
61	 * The length of time an RPC request waits in queue before
62	 * transmission, the network + server latency of the request,
63	 * and the total time the request spent from init to release
64	 * are measured.
65	 */
66	ktime_t			om_queue,	/* queued for xmit */
67				om_rtt,		/* RPC RTT */
68				om_execute;	/* RPC execution */
69	/*
70	 * The count of operations that complete with tk_status < 0.
71	 * These statuses usually indicate error conditions.
72	 */
73	unsigned long           om_error_status;
74} ____cacheline_aligned;
75
76struct rpc_task;
77struct rpc_clnt;
78
79/*
80 * EXPORTed functions for managing rpc_iostats structures
81 */
82
83#ifdef CONFIG_PROC_FS
84
85struct rpc_iostats *	rpc_alloc_iostats(struct rpc_clnt *);
86void			rpc_count_iostats(const struct rpc_task *,
87					  struct rpc_iostats *);
88void			rpc_count_iostats_metrics(const struct rpc_task *,
89					  struct rpc_iostats *);
90void			rpc_clnt_show_stats(struct seq_file *, struct rpc_clnt *);
91void			rpc_free_iostats(struct rpc_iostats *);
92
93#else  /*  CONFIG_PROC_FS  */
94
95static inline struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt) { return NULL; }
96static inline void rpc_count_iostats(const struct rpc_task *task,
97				     struct rpc_iostats *stats) {}
98static inline void rpc_count_iostats_metrics(const struct rpc_task *task,
99					     struct rpc_iostats *stats)
100{
101}
102
103static inline void rpc_clnt_show_stats(struct seq_file *seq, struct rpc_clnt *clnt) {}
104static inline void rpc_free_iostats(struct rpc_iostats *stats) {}
105
106#endif  /*  CONFIG_PROC_FS  */
107
108#endif /* _LINUX_SUNRPC_METRICS_H */
109