xref: /linux/include/linux/sunrpc/metrics.h (revision 0898782247ae533d1f4e47a06bc5d4870931b284)
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 
35 struct 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 
76 struct rpc_task;
77 struct rpc_clnt;
78 
79 /*
80  * EXPORTed functions for managing rpc_iostats structures
81  */
82 
83 #ifdef CONFIG_PROC_FS
84 
85 struct rpc_iostats *	rpc_alloc_iostats(struct rpc_clnt *);
86 void			rpc_count_iostats(const struct rpc_task *,
87 					  struct rpc_iostats *);
88 void			rpc_count_iostats_metrics(const struct rpc_task *,
89 					  struct rpc_iostats *);
90 void			rpc_clnt_show_stats(struct seq_file *, struct rpc_clnt *);
91 void			rpc_free_iostats(struct rpc_iostats *);
92 
93 #else  /*  CONFIG_PROC_FS  */
94 
rpc_alloc_iostats(struct rpc_clnt * clnt)95 static inline struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt) { return NULL; }
rpc_count_iostats(const struct rpc_task * task,struct rpc_iostats * stats)96 static inline void rpc_count_iostats(const struct rpc_task *task,
97 				     struct rpc_iostats *stats) {}
rpc_count_iostats_metrics(const struct rpc_task * task,struct rpc_iostats * stats)98 static inline void rpc_count_iostats_metrics(const struct rpc_task *task,
99 					     struct rpc_iostats *stats)
100 {
101 }
102 
rpc_clnt_show_stats(struct seq_file * seq,struct rpc_clnt * clnt)103 static inline void rpc_clnt_show_stats(struct seq_file *seq, struct rpc_clnt *clnt) {}
rpc_free_iostats(struct rpc_iostats * stats)104 static inline void rpc_free_iostats(struct rpc_iostats *stats) {}
105 
106 #endif  /*  CONFIG_PROC_FS  */
107 
108 #endif /* _LINUX_SUNRPC_METRICS_H */
109