1/*
2 *  linux/include/linux/sunrpc/metrics.h
3 *
4 *  Declarations for RPC client per-operation metrics
5 *
6 *  Copyright (C) 2005	Chuck Lever <cel@netapp.com>
7 *
8 *  RPC client per-operation statistics provide latency and retry
9 *  information about each type of RPC procedure in a given RPC program.
10 *  These statistics are not for detailed problem diagnosis, but simply
11 *  to indicate whether the problem is local or remote.
12 *
13 *  These counters are not meant to be human-readable, but are meant to be
14 *  integrated into system monitoring tools such as "sar" and "iostat".  As
15 *  such, the counters are sampled by the tools over time, and are never
16 *  zeroed after a file system is mounted.  Moving averages can be computed
17 *  by the tools by taking the difference between two instantaneous samples
18 *  and dividing that by the time between the samples.
19 *
20 *  The counters are maintained in a single array per RPC client, indexed
21 *  by procedure number.  There is no need to maintain separate counter
22 *  arrays per-CPU because these counters are always modified behind locks.
23 */
24
25#ifndef _LINUX_SUNRPC_METRICS_H
26#define _LINUX_SUNRPC_METRICS_H
27
28#include <linux/seq_file.h>
29#include <linux/ktime.h>
30#include <linux/spinlock.h>
31
32#define RPC_IOSTATS_VERS	"1.0"
33
34struct rpc_iostats {
35	spinlock_t		om_lock;
36
37	/*
38	 * These counters give an idea about how many request
39	 * transmissions are required, on average, to complete that
40	 * particular procedure.  Some procedures may require more
41	 * than one transmission because the server is unresponsive,
42	 * the client is retransmitting too aggressively, or the
43	 * requests are large and the network is congested.
44	 */
45	unsigned long		om_ops,		/* count of operations */
46				om_ntrans,	/* count of RPC transmissions */
47				om_timeouts;	/* count of major timeouts */
48
49	/*
50	 * These count how many bytes are sent and received for a
51	 * given RPC procedure type.  This indicates how much load a
52	 * particular procedure is putting on the network.  These
53	 * counts include the RPC and ULP headers, and the request
54	 * payload.
55	 */
56	unsigned long long      om_bytes_sent,	/* count of bytes out */
57				om_bytes_recv;	/* count of bytes in */
58
59	/*
60	 * The length of time an RPC request waits in queue before
61	 * transmission, the network + server latency of the request,
62	 * and the total time the request spent from init to release
63	 * are measured.
64	 */
65	ktime_t			om_queue,	/* queued for xmit */
66				om_rtt,		/* RPC RTT */
67				om_execute;	/* RPC execution */
68} ____cacheline_aligned;
69
70struct rpc_task;
71struct rpc_clnt;
72
73/*
74 * EXPORTed functions for managing rpc_iostats structures
75 */
76
77#ifdef CONFIG_PROC_FS
78
79struct rpc_iostats *	rpc_alloc_iostats(struct rpc_clnt *);
80void			rpc_count_iostats(const struct rpc_task *,
81					  struct rpc_iostats *);
82void			rpc_count_iostats_metrics(const struct rpc_task *,
83					  struct rpc_iostats *);
84void			rpc_print_iostats(struct seq_file *, struct rpc_clnt *);
85void			rpc_free_iostats(struct rpc_iostats *);
86
87#else  /*  CONFIG_PROC_FS  */
88
89static inline struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt) { return NULL; }
90static inline void rpc_count_iostats(const struct rpc_task *task,
91				     struct rpc_iostats *stats) {}
92static inline void rpc_count_iostats_metrics(const struct rpc_task *task,
93					     struct rpc_iostats *stats)
94{
95}
96
97static inline void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt) {}
98static inline void rpc_free_iostats(struct rpc_iostats *stats) {}
99
100#endif  /*  CONFIG_PROC_FS  */
101
102#endif /* _LINUX_SUNRPC_METRICS_H */
103